fatigue analysis report_ final

Fatigue Analysis Report 2011-1-0610-403-GRO1

Table of ContentsExecutive Summary..............................................................................................................................3

Hypothesis...........................................................................................................................................5

Introduction and Background...............................................................................................................5

Alternate Experiments.........................................................................................................................6

Results and Conclusion.........................................................................................................................7

Appendix A..........................................................................................................................................8

Part Measurements& Initial Calculations................................................................................................8

Appendix B..........................................................................................................................................9

Initial S/N Diagram...................................................................................................................................9

Completed Post Annealed S/N Diagram................................................................................................11

Appendix C.........................................................................................................................................13

Finite Element Analysis..........................................................................................................................13

Appendix D........................................................................................................................................20

Fatigue Test...........................................................................................................................................20

Pre-Annealed Fatigue Testing............................................................................................................20

Post Annealed Fatigue Testing...........................................................................................................25

Appendix E.........................................................................................................................................28

Tensile Testing.......................................................................................................................................28

Tensile Test of the pre-annealed Samples.........................................................................................28

Tensile Test of the post-annealed Samples.......................................................................................30

Appendix F.........................................................................................................................................32

Hardness................................................................................................................................................32

Pre Annealed Hardness Testing.........................................................................................................32

Post Annealed Hardness Testing.......................................................................................................34

Appendix G........................................................................................................................................36

Combustion-Infrared Absorption...........................................................................................................36

Appendix H........................................................................................................................................38

Spark Test..............................................................................................................................................38

Rochester Institute of Technology 1


Appendix I..........................................................................................................................................40

Metallography.......................................................................................................................................40

Pre-Annealed Metallography Test.....................................................................................................40

Post-Annealed Metallography Test...................................................................................................43

Appendix J.........................................................................................................................................45

Annealing...............................................................................................................................................45

Appendix K.........................................................................................................................................46

Cost Analysis..........................................................................................................................................46

Appendix L.........................................................................................................................................47

Green Belt Tools....................................................................................................................................47

Project Charter..................................................................................................................................47

Gantt chart.........................................................................................................................................49

Stages of Team Development............................................................................................................50

PDCA..................................................................................................................................................51

Process Flow Chart............................................................................................................................52

High Level SIPOC................................................................................................................................53

Box Plot Statistics on Testing.............................................................................................................54

Two Sample T-Test: Non Annealed/Annealed...................................................................................56

ANOVA...............................................................................................................................................58

Cause and Effect Fatigue Diagram.....................................................................................................60

Cause and Effect Material Diagram...................................................................................................61

C & E Checklist...................................................................................................................................62

Appendix M.......................................................................................................................................63

Meeting Notes.......................................................................................................................................63

References.............................................................................................................................................65



Executive SummaryTo accurately understand the failure characteristics of materials, an investigation on 10 specimens of AISI 1018 Cold Rolled steel was undertaken. The test specimens were initially fatigue tested under fully reversed load conditions in a cantilever beam model.

To begin to understand the failure characteristics the 10 specimens were stressed in a fatigue tester. Rotating at an average of 3450 rpm and loaded at one end, similar to a cantilever beam. Loads varied on a team to team basis, but were in the range of published data of AISI 1018 CRS steel’s mean strength (Sm) and Endurance Limit (Se). The loads ranged from 90N to 175N.

An S-N Diagram for the material was generated based on the correction factors estimated from the published values. The completed “corrected” S-N diagram was our starting point.

The S-N diagram was referenced to determine load characteristics required for the fatigue test. The 10 specimens were individually loaded into the fatigue tester. Once the machine was fully operational the load was introduced to the free end by rotating the dial knob on the machine. It took about 1000-2000 revolutions before the specimen reached the desired load value for each test run. This variation, in what should have been a constant load was negligible for the overall experiment.

The trend with the load and its expected number of cycles to failure showed a much higher mean strength. This translated to a much higher Ultimate Tensile Strength being found from the test values. The results showed a nearly 29% increase compared to the expected value. The expected value was 65.3ksi and experimental value was calculated as 84.2ksi.

This created many doubts as to the authenticity of the material or the process of fabrication. As a class, it was established that either the material was not actually 1018 CRS, or the fabrication process induced significant internal stresses by process of work hardening the specimen.

To confirm our hypothesis of the material two groups of experiments and testing were done. One test involved the authentication of the material, while the other involved the possibility of internal stresses.

In an attempt to verify the quality of output of the fatigue tester, parts of the 10 initial specimens were tensile tested. The Tensile tests results corresponded with the fatigue test giving an average Sut of 100.4ksi. The different between the results of the fatigue test and tensile test were relatively close but still substantially high compared to the critical to quality value of 65.3ksi. The results between the fatigue and tensile test were neglected, due to the bigger issue. These differences may have occurred due to specimen loading conditions, system calibration errors or other random errors.



To further verify the results a Rockwell Hardness test was conducted on the specimens. The hardness test results showed an average ultimate tensile strength of 98ksi.

After three multiple test results, all verifying an accurate read of 80+ Sut, a spark test was performed to confirm the carbon content. A Combustion test performed by an outsourced laboratory, IMR Test Labs, also confirmed the carbon content of 1 specimen as 0.19% of weight. This test result indicted the specimens were in fact AISI 1018 Cold Rolled Steel.

At this point it was clear that the only variance that had not formally been taken into account was manufacturing process. Work hardened materials deviate from most published values, as was observed through test experiments. However, this claim needed to be backed up. A metallurgical grain structure test would enable us to read the grain structure of our specimens and compare it to published data from the American Metallurgical Society. Studying the specimens under a high powered microscope, visually the data corresponded with that of published images. However, photographs were not conclusive enough, or a reliable source of data to draw any conclusion; There can be errors such as human eye errors.

At this point it was verified that we know the samples were of AISI 1018 CRS. To bring the Sut down closer to its published values within 3-4% range, a set of new 1018 CRS specimens from which the same batch the original was received. These specimens were put into a furnace to undergo full annealing. Upon the completion of the annealing process, the five specimens were then re-tested for fatigue, tensile, hardness and metallurgy. The results of the post annealed specimens were found to be close to published value of 65.3ksi within 3-4%. Therefore, as hypothesized, the material of the specimens was in fact AISI 1018 Cold Rolled Steel which was induced with internal stresses.

To effectively complete this project, Six Sigma tools were utilized to better define, measure, analyze, improve and control (DMAIC) the main objective and customer need which was to determine the fatigue characteristics of given samples of AISI 1018 cold rolled steel. Tools such as project plan using a Gantt chart, process flow chart, diagrams, brainstorming, PDCA, ANOVA, SIPOC, two sample T-test, box plots, and cost analysis were incorporated into the report to be better organized & utilize the DMAIC process.



HypothesisAfter conducting the fatigue analysis experiments, we encountered a problem. The actual fatigue data was significantly higher than both the published and calculated corrected data. We suspect that the cause of this material's increase in fatigue characteristics is a result of strain hardening that occurred during the cold drawing manufacturing process of these specimens. To verify our suspicions, we will conduct a series of tests to verify the SUT of the specimens. This will ensure that there was no major error during the fatigue testing of the material. Spark and metallurgy test will be done to verify that material is actually 1018 CRS. At the completion of these tests, we should be able to conclude that the material is still in fact 1018 CRS with an increase in SUT due to strain hardening during manufacturing process of the specimens.

Introduction and BackgroundFor the 2011 fall quarter Failure Mechanics class, a CTQ (Critical to Quality) was given to determine the fatigue characteristics of AISI 1018 CRS within a 99% confidence level and compare them to the published values. In the process of reaching this CTQ, Six Sigma tools were utilized. With these found fatigue characteristics, analysis were to be done to show the general applicable engineering design in terms of safety factors.

The failure of materials theoretically occurs at much lower stress levels than the published values of the ultimate tensile strength (SUT). An important part of Failure Mechanics is to understand the conditions of bodies that incur alternating stresses under cyclic loading. With this understanding, predictions of failure can be achieved, and designs can be created at variable FOS (Factors of Safety) for different applications.

Using a fatigue tester is a favorable way to test the fatigue characteristics of a material. Usage of this machine requires knowledge of Failure Mechanics and strength of materials in order to utilize the data from this machine. With this knowledge a controlled set of test can be conducted and the data can be interrupted into a SUT. This is achieved with the creation of a SN-Diagram (Stress vs. Number of cycles). To further constrain that the material and verify the material properties, other test can be conducted. These test include, hardness, metallurgy, spark, and tensile test. A collection of this data and published data will provide controlled fatigue characteristics with verified material properties.



Alternate ExperimentsTo qualify the legitimacy of the Fatigue test results, a tensile test and a Hardness test were performed. The specimens used for both these experiments were parts of the broken specimens from the fatigue tests. For all the following experiments parts of the same specimens used for the fatigue test were used. This was to ensure no corruption of the sample set. For the Tensile test the neck of the specimen was used.

Tensile test results, performed on 4 specimens were concurrent with those from the fatigue test. The average ultimate tensile strength derived from the experiment was 100ksi. The tensile test was however not enough evidence to dismiss either one of the hypothesis. A hardness test was then performed on 4 samples of the fatigue test. The average HRB number derived from the hardness test was 94.4 HRB. According to the Rockwell Hardness Conversion charts this indicted an ultimate tensile strength of approximately 98ksi.

The results of the Tensile and Hardness test were concurrent with those of the Fatigue test. Precise results did not however account for accuracy. The investigation then leaned towards proving the authenticity of the specimens’ material. To conclude the specimen was in fact AISI 1018 Cold Rolled Steel, a spark test, Combustion test, and Metallographic test were performed.

The spark test was visually conclusive. The spark profiles matched those of low to medium carbon steel alloys. This indicted the carbon content was between 0.15% and 0.20% of weight of the material. This is characteristic of low carbon steels, under which 1018 CRS falls.

The combustion test was more precise. It was outsourced to IMR Testing Labs due to the lack of testing equipment here at RIT. IMR Testing Labs reported a carbon content of 0.19% of weight. This matched the requirements of AISI 1018 Carbon Steel according to UNS-G-10180 standards.

The Metallographic test helped observe the grain structure of the specimens. Polished and acid etched image results determined that the grain structure was similar to published images characteristic to low carbon steels.

After performing all these tests, it was conclusive that the specimens were in fact AISI 1018 CRS, but the anomaly of the results being higher than its published/expected Sut is due to the presence of internal stresses. So to bring down the ultimate tensile strength value to a more acceptable range, it was decided that a full annealing process will have to be done. A batch of the same specimens were taken and thrown into the annealing oven to have them fully annealed. Upon annealing of these specimens, the group received 5 specimens, and the



same fatigue, tensile, hardness and metallurgic tests were performed all over again to compare the post annealed data to that of the pre annealed data. The results of these tests were found to be closer to published values within 3-4 percent variance. The average ultimate tensile strength indicated by the annealed specimens was 62.5ksi. A two sample T-test was made to compare the pre annealed and post annealed data, as part of the Six Sigma tools. This observation led to the conclusion that the material was accurately provided by the supplier. It was 1018 Cold Rolled Steel and the failure characteristics are in accordance to published data.

Six Sigma Tools incorporated in the fatigue analysis report:

Project Charter Gantt Chart Stages of Team Development Plan Do Check Act Process Flow Chart High Level SIPOC Box Plot Two Sample T-test ANOVA Cause and Effect Diagrams C & E Checklist Cost Analysis

Results and ConclusionAfter performing multiple tests on the given sample specimens it is likely that they are AISI 1018 CRS. To confirm the material a vast number of other aspects must be researched. The manufacturing process would tell us a lot more about the components of the material.

All test performed qualify the presence of internal stresses in the material. There is minimal evidence in this investigation that leads to conclusively verify that the material is 1018 CRS. Had specimens of 1015 CRS or 1020 CRS been tested, with a 4% variance in results the collected data would conclude the same most probably. The material exhibits characteristics of 1018 CRS but is not conclusive enough to accurately determine the ingredients of the material. However, the objective of the investigation was accurately met. Its failure conditions and behavior under these conditions were accurately charted. To verify material components accurately, further investigation and experiments would be necessary.



Appendix A

Part Measurements& Initial Calculations

1018 Cold Rolled Steel SUT= 65,300psi

D= 0.500” d= 0.3125”

Length= 4.125” r= 0.1563”

rd=0.1563 } over {0.3125=.24 D

d=0.500

.3125=1.6*

KT= 1.51 (Reference Figure C-1, (Norton, Page 1000))

L=4.125-0.3125= 3.8125”= Moment Arm

*Note: Based on Figure C-1, there is a given curve for 2.0 & 1.5 with values for KT of 1.5 & 1.55 respectively. Therefore we made a linear interpolation to obtain the value of 1.51 for KT.

Area Moment of Inertia= I=π d4

64=π ¿¿¿

Avg. Surface CTemp CReliability CLoad Csize Csurface Corr. Factor86.28μ” 1 0.702 1 0.778 0.975 0.5325

SUT’= Corr.Factor× SUT

σ max=MCI→ F× L×r

I=F×3.8125 ×0.1563} over {4.68× {10} ^ {-4} {in} ^ {4} ¿

σ max=F ×1272.87

σmax1272.87

=F(lbs)σmax

286.18=F (N )

Se’= SUT × 0.5= 32,650 psi

Se=Se’×CTemp×CReliability×CLoad×Csize×Csurface

Se= 32,650 psi × 0.5325Se= 17.386 psiSm=SUT × 0.9= 58,770 psi



Appendix B

Initial S/N DiagramS-N Diagram and Force Values for Fatigue Testing

RevsPublishe

dCorrecte

d0 65300 65300

1.0E+03 58770 587701.0E+06 32650 173861.0E+09 32650 17386

Projected numbersActual

Rev

Actual Minute

sSampleStress (psi) Revs

Force (N)

Minutes

1 50000 4320 175 1.22 78697 22.172 48000 6030 168 1.70 80624 22.713 46000 8420 161 2.37 85440 24.074 44929 10070 157 2.84 103119 29.055 42640 14760 149 4.16 114689 32.316 40065 22680 140 6.39 108647 30.607 38061 31690 133 8.93 297435 83.788 36344 42210 127 11.89 522331 147.149 34341 58960 120 16.61 354164 99.76

10 25756 87150 90 24.55385303

5 1085.36

1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+070

10000

20000

30000

40000

50000

60000

70000

f(x) = − 5990.94761302806 ln(x) + 100154

Corrected

CorrectedLogarithmic (Corrected)



Completed Post Annealed S/N Diagram

RevsPublishe

dCorrecte

d0 65300 65300

1.0E+03 58770 587701.0E+06 32650 173861.0E+09 32650 17386

Post Anneal Revs


Rev

Actual Minute

sSampleStress (psi) Revs

Force (N)

Minutes

1 50000 4320 175 1.22 78697 22.17 40632 48000 6030 168 1.70 80624 22.713 46000 8420 161 2.37 85440 24.07 63204 44929 10070 157 2.84 103119 29.055 42640 14760 149 4.16 114689 32.31 80196 40065 22680 140 6.39 108647 30.607 38061 31690 133 8.93 297435 83.78 187708 36344 42210 127 11.89 522331 147.149 34341 58960 120 16.61 354164 99.76 24980

10 25756 87150 90 24.55385303

51085.3

6

Pre-Anneal

Post Anneal

Tensile 100 ksi 62 ksiHardnes

s 98 ksi 57.8 ksi



Appendix C

Finite Element AnalysisExecutive Summary

Finite Element Analysis is a powerful tool that can be used to analyze complex stress situations on multiple parts. When used properly it can find solutions to problems that are too complex for classical closed-form methods of stress deflection analysis. If these calculations are done by hand, it is too easy to miss certain stress concentrations that the software is programmed to pick up on. The FEA software expedites and standardizes the process so accurate calculations are consistently created.

Model Information



Model name: Part1-1

Current Configuration: Default

Solid BodiesDocument Name and

Reference Treated As Volumetric PropertiesDocument Path/Date

ModifiedChamfer1

Solid Body

Mass:0.0795517 kgVolume:1.01082e-005 m^3

Density:7870 kg/m^3Weight:0.779606 N

C:\Users\Ars1080\AppData\Local\Temp\

Part1-1.SLDPRTNov 07 15:11:41 2011

Units

Unit system: SI (MKS)Length/Displacement mm

Temperature KelvinAngular velocity Rad/secPressure/Stress N/m^2



Material Properties

Model Reference Properties Components

Name: AISI 1018 Steel, Cold Rolled

Model type: Linear Elastic IsotropicDefault failure

criterion:Max von Mises Stress

Yield strength: 50763.2 psiTensile strength: 60915.8 psiElastic modulus: 2.97327e+007 psiPoisson's ratio: 0.29Mass density: 0.284322 lb/in^3

Shear modulus: 1.1603e+007 psiThermal expansion

coefficient:6.5e-006 /Fahrenheit

SolidBody 1(Chamfer1)(Part1-1)

Curve Data:N/A

Loads and Fixtures

Fixture name Fixture Image Fixture Details

Fixed-2

Entities: 1 face(s)Type: Fixed Geometry

Resultant ForcesComponents X Y Z Resultant

Reaction force(N) -0.0023194 100.791 0.00255805 100.791Reaction Moment(N-m) 0 0 0 0



Load name Load Image Load Details

Gravity-1

Reference: Top PlaneValues: 0 0 -9.81

Units: SI

Remote Load (Direct

transfer)-1

Entities: 1 face(s)Type: Load (Direct transfer)

Coordinate System: Global cartesian coordinatesForce Values: ---, -100, --- N

Moment Values: ---, ---, --- N-mReference coordinates: 5.5 0.15625 0 in

Components transferred: Force



Mesh Information

Mesh type Solid MeshMesher Used: Standard meshAutomatic Transition: OffInclude Mesh Auto Loops: OffJacobian points 4 PointsElement Size 0.0851578 inTolerance 0.00425789 inMesh Quality High

Total Nodes 11285Total Elements 6862Maximum Aspect Ratio 7.5232% of elements with Aspect Ratio < 3 98.8% of elements with Aspect Ratio > 10 0% of distorted elements(Jacobian) 0Time to complete mesh(hh;mm;ss): 00:00:02Computer name: 719-70-1130-04

Resultant Forces



Reaction Forces

Selection set Units Sum X Sum Y Sum Z ResultantEntire Model N -0.0023194 100.791 0.00255805 100.791

Reaction Moments

Selection set Units Sum X Sum Y Sum Z ResultantEntire Model N-m 0 0 0 0

Study Results

Name Type Min MaxStress1 VON: von Mises Stress 7.66339e-007 ksi

Node: 84129.774 ksiNode: 331

Part1-1-Study 1-Stress-Stress1

Name Type Min MaxDisplacement1 URES: Resultant Displacement 0 in 0.0309513 in



Name Type Min MaxNode: 8 Node: 330

Name Type Min MaxStrain1 ESTRN: Equivalent Strain 1.06866e-010

Element: 44900.000690231Element: 2346



Conclusion

In this specific FEA analysis, you can quickly determine where the part incurs the most stress in the model. The distributed von MISES stress throughout the part range from 7.66339e-007 ksi to 29.774 ksi. These numbers are not as important as the proportion of the stresses throughout the specimen. Error could have occurred in the calculation of the stress due to user error. But the distribution of the stresses in the model still holds true. The most important distribution of stress to concentrate on is the ones located at the fillet. More specifically speaking, the greatest stress will be at the point of fixation, furthest from the load. This is important to further investigate during the design of this part and during the fatigue analysis of this cantilever beam.

You can also find from this FEA analysis is the areas in which the cantilever beam incurs the greatest defection. The specimen is under a load and in reverse bending. Due to the moment force, the point of fixation is undergoing the most stress. The point where the most deflection occurs is at the load. A significant amount of deflection is shown in the diagrams and illustrated with the colors and scale.



Appendix D

Fatigue Test

Pre-Annealed Fatigue TestingExecutive Summary

The goal of this experiment was to find the ultimate strength of 1018 CRS and compare it to the published data. 10 specimens were given to us by our boss and each specimen will be tested at various loads based on our initial calculations. All of the data collected from the fatigue tests will be compiled together to create an S-N Diagram to find the ultimate strength of the 1018 samples. The 10 specimens were tested at forces ranging from 90N to 175N. The fatigue tester operated at 3450 revolutions per minute. After gathering all of the data and drawing a new logarithmic line, the ultimate strength was determine to be 84 ksi, as can be seen in the S-N Diagram (Appendix B). The ultimate strength of the tested parts was far higher than the published date for ultimate strength. Tensile and hardness tests will be performed next to see if the machine is off or the parts are out of spec and to get down to the reason why the measured data and published data are off by more than 3-4%.

Equipment Specifications

Fully reversed bending analysis was performed on a standard G.U.N.T Fatigue Testing machine manufactured by G.U.N.T. Hamburg GmbH, Germany. The equipment specifications are as follows:

Motor

Speed: 3450 rpm Output: 0.37kW

Load

0- 300 Newton’s

Load Cycle Counter

Electronic 8-digit digital display



Can be switched to display speed

The machine was ideal for performing a fully reversed bending test on a small scale. The fully reversed condition is achieved as the specimen rotates with the top half of the profile in tension while the bottom half in compression. Due to excessive, long term usage it was suspected the motor output would differ from the manufacturing specifications. We took a reading of the RPM and got results back showing that it wasn’t off by much. During operational conditions there would be a substantial amount of load on the test specimen. This load would generate higher friction that the motor would have to overcome. This could potentially have lowered the speed at which the machine ran.

Goals and Objectives

Fatigue testing of all ten specimens and use the data to create a new logarithmic line to calculate the measured ultimate strength of the 1018 CRS.

Procedure

As a starting point an estimated S-N Diagram was constructed. This helped chart the likely pattern that a sample of AISI 1018 Cold Rolled Steel would impersonate. The estimate S-N diagram was used as reference to determine the load conditions for the actual experiment. Taking the number of cycles as the independent variable, loads ranging from 90-175N were determined. The load range was then divided and each of the 10 specimens was assigned a load value. Once loaded into the fatigue tester the specimens were tested and the number of cycles to breakpoint was noted and plotted on the S-N Diagram.

Data& Graph

Projected numbers Actual Rev

Actual MinutesSample Stress (psi) Revs Force (N) Minutes

1 50000 4320 175 1.22 78697 22.17

2 48000 6030 168 1.70 80624 22.71

3 46000 8420 161 2.37 85440 24.07

4 44929 10070 157 2.84 103119 29.05

5 42640 14760 149 4.16 114689 32.31

6 40065 22680 140 6.39 108647 30.60

7 38061 31690 133 8.93 297435 83.78

8 36344 42210 127 11.89 522331 147.14

9 34341 58960 120 16.61 354164 99.76

10 25756 87150 90 24.55 3853035 1085.36



Results Analysis:

During the experiment, there was a noticeable difference in revolutions required to cause failure. This difference was further emphasized with a visual comparison between expected data points and actual data point. Comparing the expected and actual results on the S-N Diagram we see how the actual data resulted in a change in the expected Se, Sm and Sut. The published value for the 1018 CRS is 65.3 ksi and the value projected by this data set is 84.2 ksi. This is about a 29% error between the two sets of data.

Error Evaluation

As mentioned previously, our specimens took longer to break than we had anticipated. This inaccuracy of results may have been caused due to a number of factors such as system errors, calibration offsets, human errors, loading condition faults, the wrong material being provided by the supplier, etc. One thing though, the precision of the results following a path similar to expected path, though offset, proves that random errors were negligible. The further this test issue, and determine why our data was off by so much, we will be performing additional tests, including hardness and tensile.



Fatigue (All Groups)Grou

p psi Ksi RevsGrou

p psi Ksi RevsGrou

p psi Ksi Revs

1,1

50120

50.1 92765

1,4

55000

55.0 36874

1,7

52750

52.8 49228

46700

46.7 74593 5300

053.0 41441 4900

049.0 53427

43700

43.7 171770 4900

049.0 110696 4710

047.1 70320

40870

40.9 135990 4600

046.0 80430 4450

044.5 86027

37600

37.6 314187 4200

042.0 24696 4075

040.8 122848

34100

34.1

1269818

41000

41.0 158725 3890

038.9 108295

54800

54.8 48330 3800

038.0 213696 3675

036.8 215479

39210

39.2 151716 3400

034.0 164803 3330

033.3 NB

50170

50.2 89575 2900

029.0 687565 3050

030.5 588000

54500

54.5 54326 2750

027.5 NB 2775

027.8

1300000

1,2

50653 177 6348 5100

051.0 75356

2,1

50000

50.0 78697

46933 164 72309 4600

046.0 116434 4800

048.0 80624

34341 120 68209 4200

042.0 83371 4600

046.0 85440

44071 154 81616

1,5

42776

42.8 127447 4500

045.0 103119

40351 141 129102 4061

640.6 85375 4300

043.0 114689

37489 131 299223 3845

738.5 128596 4000

040.0 108647

31479 110 419308 3560

835.6 326093 3800

038.0 297435

29190 102 625383 2741

527.4

1248645

36000

36.0 522331

34402

34.4 462652 3400

034.0 354164

2956 29. 945661 2600 26. NB



5 6 0 0

1,3

56000

56.0 63,274 3187

131.9 136044

2,2

42000

42.0 69906

53000

53.0 31,317 3113

731.1 713505 4600

046.0 81565

50000

50.0 59,459 3026

230.3 811032 3700

037.0 242056

47000

47.0 29,603

1,6

60088

60.1 47196 3900

039.0 162536

44000

44.0 91,061 5783

557.8 56850 3500

035.0 313827

41000

41.0 182,538 5483

054.8 60469 4100

041.0 126482

38000

38.0 324,223 5257

752.6 175201 4400

044.0 84841

35000

35.0 401,379 5032

450.3 129368 3100

031.0 971272

32000

32.0 748,225 4731

947.3 145139 3300

033.0 669313

29000

29.0

2845198

45066

45.1 198444 3400

0 34 339841

42813

42.8 272859

39808

39.8 264111

37555

37.6 281022



Group Sut1,1 86.61,2 67.01,3 79.21,4 82.41,5 66.41,6 164.41,7 85.32,1 84.22,2 73.9



Post Annealed Fatigue TestingExecutive Summary

The goal of this experiment was to find the ultimate strength of annealed samples of 1018 CRS and compare it to the published data. Five specimens were given to us and each specimen is to be tested at various loads based on our initial calculations. All of the data collected from the fatigue test will be compiled together to create an S-N Diagram to calculate the ultimate strength of the 1018 samples. The five samples were tested at forces ranging from 120N to 175N. The fatigue tester operated at approximately 3450 revolutions per minute. After gathering all of the data and drawing a new logarithmic line, the ultimate strength was determine to be 67.5 ksi as can be seen in the S-N Diagram (Appendix B). The ultimate strength of the tested parts was 3.4% higher than the published date for ultimate strength. Tensile and hardness tests will be performed to further verify this value.

Equipment Specifications

Fully reversed bending analysis was performed on a standard G.U.N.T Fatigue Testing machine manufactured by G.U.N.T. Hamburg GmbH, Germany. The equipment specifications are as follows:

Motor

Speed: 3450 rpm Output: 0.37kW

Load

0- 300 Newton’s

Load Cycle Counter

Electronic 8-digit digital display Can be switched to display

speed

The machine was ideal for performing a fully reversed bending test on a small scale. The fully reversed condition is achieved as the specimen rotates with the top half of the profile in tension while the bottom half in compression. Due to excessive, long term usage it was suspected the motor output would differ from the manufacturing specifications. We took a reading of the RPM and got results back suggesting that it was close to its specified speed. During operational conditions there would be a substantial amount of load on the test



specimen. This load would generate higher friction that the motor would have to overcome. This could have potentially reduced the speed of the machine under load.


Fatigue testing five annealed specimens and use the data to create a new logarithmic line to calculate the measured ultimate strength of the annealed 1018 CRS, then compare it to both the pre-annealed values as well as the published value.

Procedure

As a starting point an estimated S-N Diagram was constructed. This helped chart the likely pattern that a sample of AISI 1018 Cold Rolled Steel would impersonate. The estimate S-N diagram was used as reference to determine the load conditions for the actual experiment. Taking the number of cycles as the independent variable, loads ranging from 120-175N were determined. The load range was then divided and each of the five specimens was assigned a load value. Once loaded into the fatigue tester the specimens were tested and the number of cycles to breakpoint was noted and plotted on the S-N Diagram.

Data& Graph


RevActual

Minutes

Post Anneal

RevSampleStress (psi) Revs

Force (N)

Minutes

1 50000 4320 175 1.22 78697 22.17 40632 48000 6030 168 1.70 80624 22.713 46000 8420 161 2.37 85440 24.07 63204 44929 10070 157 2.84 103119 29.055 42640 14760 149 4.16 114689 32.31 80196 40065 22680 140 6.39 108647 30.607 38061 31690 133 8.93 297435 83.78 187708 36344 42210 127 11.89 522331 147.149 34341 58960 120 16.61 354164 99.76 24980

10 25756 87150 90 24.55385303

51085.3

6



Results Analysis:

During the experiment, there was a difference in time required to failure point, although it was far less than that of the non- annealed samples. Comparing the expected and actual results on the expected S-N Diagram we see how the actual data resulted in a change in the expected Se, Sm and Sut. The theoretical value for the 1018 CRS should be 65.3 ksi and our value came out to be 67.5 ksi. This is about a 3.4% error between the two sets of data.

Error Evaluation

The inaccuracy of results may have been caused due to a number of factors such as system errors, calibration offsets, human errors, loading condition faults, the wrong material being provided by the supplier, etc. The precision of the results following a path similar to expected path, though offset, proves that random errors were negligible. Overall, the samples were within 4% of the published data, so further testing will help define the tested ultimate tensile strength of the material.

Appendix E

Tensile Testing

Tensile Test of the pre-annealed SamplesExecutive Summary

To confirm the ultimate tensile strength of the specimens and to compare them to and validate the fatigue testing results, tensile testing was performed on four specimens. By measuring the parts to find the area broken and using the MTS Universal Testing machine, we were able to obtain the ultimate tensile strength for those specimens. An average tensile strength of 100 ksi was recorded, with a standard deviation of 6.2 ksi. This average was considerably higher than the ultimate strength projected by our fatigue results.

Equipment

Tensile Tester

Goals & Objectives



The goal of this experiment was to determine the ultimate tensile strength of four of the specimens of 1018 cold rolled steel. This value could then be compared to the projected ultimate strength from the fatigue values.

Procedure

Four samples (samples 1, 2, 3, and 4 as labeled from fatigue testing) were tested in the Universal Testing Insight tensile testing machine. The machine was set up to hold the size specimen we were using, then the piece was secured inside. The sample was first secured in the upper vice and then slowly lowered into the lower vice, and secured there. A strain gauge was attached to the specimen and the machine was started. Once prompted, the strain gauge was removed and the test continued until fracture. The stress and strain figured were recorded by the computer. The specimen was then removed than the process was repeated.

Data

All Specimen Graph



0

10

20

30

40

50

60

70

80

90

100

110

0 2 4 6 8 10 12 14 16 18 20 22 24

Stress (ksi)

Strain (%)

123[4]

Individual Specimen Graphs

Specimen # : 1

0

10

20

30

40

50

60

70

80

90

100

110

0 1 2 3 4

Stress (ksi)

Strain (%)

[1]

F

B

M

OY

UTS

Specimen # : 2

0

10

20

30

40

50

60

70

80

90

100

110

0 2 4 6 8 10 12 14 16 18 20 22 24

Stress (ksi)

Strain (%)

[2]

F

B

M

OY

UTS

Specimen # : 3

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22

Stress (ksi)

Strain (%)

[3]

F

B

M

OY

UTS

Specimen # : 4

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9

Stress (ksi)

Strain (%)

[4]

F

B

M

OY

UTS

Specimen Results



Specimen #

Specimen Comment

Diameter Peak Load Peak Stress Modulus Break Stress

Stress At Offset Yield

Strain At Break %

Total Energy

Absorbed

in lbf psi psi Psi psi ft*lbf/in^2

1 Part 1 0.311 8048 105947.5 3.38E+07 1.03E+05 9.68E+04 3.326 274

2 Part 2 0.311 7969 104909.3 3.23E+07 7.52E+04 9.77E+04 23.779 1743

3 Part 3 0.312 7284 95278.6 3.24E+07 6.56E+04 8.11E+04 21.07 1598

4 Part 4 0.313 7253 94258.3 3.18E+07 7.44E+04 8.03E+04 8.973 674

Mean 0.312 7639 100098.4 3.26E+07 7.96E+04 8.90E+04 14.287 1072

Std. Dev. 0.001 429 6183.1 8.77E+05 1.63E+04 9.58E+03 9.738 712

Tensile Test of the post-annealed SamplesExecutive Summary

To confirm the ultimate tensile strength of the annealed specimens and to compare them to and validate the pre and post- annealed fatigue testing results, tensile testing was performed on five specimens. By measuring the parts to find the area broken and using the MTS Universal Testing machine, we were able to obtain the ultimate tensile strength for those specimens. An average ultimate tensile strength of 62.2 ksi was found through testing, with a standard deviation of 0.356 ksi. This average was 4.7% lower than the published value.

Equipment

Tensile Tester

Goals & Objectives

The goal of this experiment was to determine the ultimate tensile strength of five of the annealed specimens of 1018 cold rolled steel. This value could then be compared to the projected ultimate strength from the fatigue values, as well as our pre- annealing tensile values to determine differences.

Procedure



Four samples (samples 1, 2, 3, 4 and 5 as labeled from fatigue testing) were tested in the Universal Testing Insight tensile testing machine. The machine was set up to hold the size specimen we were using, then the piece was secured inside. The sample was first secured in the upper vice and then slowly lowered into the lower vice, and secured there. A strain gauge was attached to the specimen and the machine was started. Once prompted, the strain gauge was removed and the test continued until fracture. The stress and strain figures were recorded by the computer. The specimen was then removed than the process was repeated.

Specimen Results

Specimen #

Specimen Comment

Diameter Peak LoadPeak

StressModulus

Break Stress

Stress At Offset Yield

Strain At Break

Total Energy

Absorbed

in lbf Psi psi psi psi % ft*lbf/in^2

1 Part 1 0.31 4706 62347.3 3.32E+07 4.52E+04 3.95E+04 29.015 1912

2 Part 2 0.31 4669 61854.5 3.15E+07 4.48E+04 3.83E+04 31.107 2126

3 Part 3 0.313 4753 61770 3.24E+07 4.46E+04 3.82E+04 31.447 2170

4 Part 4 0.309 4687 62498.9 3.56E+07 4.50E+04 3.89E+04 32.957 2371

5 Part 5 0.309 4687 62506.8 3.08E+07 4.42E+04 3.98E+04 32.259 2290

Mean 0.31 4700 62195.5 3.27E+07 4.48E+04 3.89E+04 31.357 2174

Std. Dev. 0.002 32 356.8 1.84E+06 3.75E+02 7.08E+02 1.494 175



Appendix F

Hardness

Pre Annealed Hardness TestingExecutive Summary

To confirm the ultimate tensile strength of the fatigue and tensile tests and to validate theirs results hardness test on 4 specimens was performed. Rockwell B scale was used and correction factors were used to find the hardness of each sample. After collecting all of the data an average of 94.4 was found. By using a conversion graph, the ultimate tensile strength was found to be 98 ksi. This test helped to confirm that the ultimate tensile strength of the parts were higher than published data.

Equipment

Wilson Instruments Rockwell Hardness Tester Series 2000

Goals & Objectives

The goal of the experiment was to determine the hardness for the 4 specimens tested of the 1018 CRS. This number could then be converted to ultimate tensile strength to be compared to the published data, as well as the results from the fatigue and tensile tests.



Procedure

4 samples were tested 4 times each on the Wilson Rockwell Hardness Tester. This was a fairly simple test. The specimens were placed on the hardness testing machine. The indenter used was a hardened steel ball. This indenter is used for aluminum, brass and soft steels. The indenter’s comparative scale is the HRB. Once the samples were placed on the testing platform a mechanical arm indented it. The indentation marks left were then measured for area of indentation. The area was then cross referenced with Rockwell Conversion Charts to determine the ultimate tensile strength.

Data

Hardness Pre-Annealed Results

Part 1 HRB Actual HRB Corrected1 94 95.82 93.6 95.43 94.4 96.24 94.4 96.2

Part 21 96.4 98.4

2 96.6 98.33 96.2 97.94 96.5 98.2

Part 31 89.9 91.92 89.9 91.93 90 924 90.1 92.1

Part 41 89.4 91.42 90.4 92.43 89.1 91.14 89.4 91.4

Average= 94.41BHN= 207.99SUT= 98 ksi

The average of all the values provided a 94.4 HRB number. This is indicative of an ultimate tensile strength of roughly 98 ksi.

Published data however provides an HRB number of 71 for 1018 Cold Drawn Steel. This is a 25% deviation; 8% error range is allowed.

Error Analysis



Errors in the Hardness test may have occurred due to various reasons. The 4 times that each specimen was tested, it was tested in 4 different locations. Even by testing each sample 4 times, there can still be 4 spots chosen that do not reflect the overall mechanical properties of the material. Also, there could have been faulty results if the steel was tested too close to the edges of the sample.

Conclusion

Since the readings of the hardness test are concurrent with the results from the tensile test and the fatigue test, the results are valid. The slight errors that may have occurred are thus, negligible.

Post Annealed Hardness TestingPart 1 HRB Actual HRB Corrected Rockwell B Hardness

Numbers (HRB)Equations to Convert Rockwell B

Hardness (HRB) into Brinell Hardness (HB

1 60.9 57.3

2 63.1 59.6 from to3 60.5 56.8 55 69 HB = 1.646 x HRB + 8.74 51.5 47.4 70 79 HB = 2.394 x HRB – 42.75 53.6 49.6 80 89 HB = 3.297 x HRB – 114

Part 2 90 100 HB = 5.582 x HRB – 3191 50.3 46.12 62.1 58.53 62 58.44 56.8 52.95 62 58.4

Part 31 52.8 48.72 57 53.23 60.6 574 51.6 47.55 51.4 47.3

Part 41 32.1 272 45.7 41.33 60 56.34 61.9 58.35 57.3 53.5

Part 51 50 45.82 59.9 56.23 61.5 57.94 55.3 51.45 53.1 49.1

55.72 51.82BHN= 637.5

Average= 506.63SUT= 266 ksi



Results

After retrieving all the data from the past 4 tests on the pre annealed samples, we realized that our ultimate tensile strength was higher than the published data for cold rolled 1018 steel. In trying to lower the tensile strength of the samples, we fully annealed 5 additional samples and tested them. In order to ensure the most accurate results, we preformed four different tests to prove our samples were in fact 1018 Cold Rolled Steel. The tests that we preformed included a fatigue test, tensile test, metallurgy test and a Rockwell Hardness test.

The annealing process heats the samples to slightly below the materials austenizing temperature. Once it reaches this temperature, it begins to slow cool and over time lowers the strength of the material by making it more ductile by allowing the grain structure to return to its pre-drawn state. The results from the annealed hardness test are compared directly with results of the pre annealed hardness test of the 10 previous samples. Through the results we can see that the hardness average of the pre annealed samples are higher than that of the annealed samples. What this means is that the annealing process has made the surface of the new samples softer than the original pre annealed samples, ultimately lowering the strength of the samples to meet the published ultimate tensile strength.



Appendix G

Combustion-Infrared AbsorptionExecutive Summary

The carbon content test or otherwise known as combustion test was outsourced to IMR Testing Labs since the required equipment was unavailable to us through RIT. This test was conducted to better verify the carbon content in the specimens and help verify the Spark Test results.

IMR Testing Labs combustion tested 1 sample specimen that was received from a group in Section 1 of Failure Mechanics class. Their report concluded that the specimen has 0.19% of carbon by weight. The published characteristics of AISI 1018 Carbon steel require between 0.15% and 0.20% of carbon by weight. They also concluded that the sample met UNS-G-10180 standards for AISI 1018 Carbon Steel.

The report provided by IMR Test Labs is provided in the next page. This report has been made available by the generosity of Thomas Mordovancey from Section 1.

Error Analysis

Accounting for possible errors in this test was no possible due to an inadequacy of information pertaining to the testing method.

Conclusion

The combustion test is standard test performed by IMR Testing Labs often. In spite of a lack of information about the testing method, it was concluded that the results were conclusive.



Appendix H

Spark TestExecutive Summary

The spark test is used to determine relative molecular content of materials. In this case, the test was used to determine the relative carbon content of our steel specimens. The test involved use of a grinder and a specimen of 1018 steel. Vision and picture comparison was used to come to our conclusions. After observing the spark patterns and color, the specimen appears to be a low or mild carbon steel.

Equipment

The equipment used was a grinding wheel.

Goals & Objectives

The objective of this test was to determine a relative (mild or low, medium, or high carbon) carbon content of the specimen. The specification of the specimen could then be compared to that to see if it fell within that category.

Procedure

After the grinding wheel had come to speed, the specimen was securely held and touched to the wheel. The spark pattern was observed and photographs were taken to document the patterns.

Conclusion

Due to the leafing observed in the spark patterns, as well as very little branching, it was concluded that the samples had the spark characteristics of a mild carbon steel.

Data

There is no numeric data for this experiment, only photographs recording the spark patterns and colors.




Above: (From top to bottom) mild carbon steel, medium carbon steel, and high carbon steel spark characteristics. (Pictures from www.capeforge.com)

Left: Two pictures of a spark test performed on a sample of 1018 cold rolled steel.


Appendix I

Metallography

Pre-Annealed Metallography TestExecutive Summary

At this point it is established that the specimen is definitely AISI CRS 1018, and the results were not due to a faulty machine. The fatigue, tensile, and hardness test results all gave tensile strengths that were far above the published data. We are now assuming that the steel must have been malformed to produce different results and is suspected that some cold-working has happened. A metallurgical test was performed to prove this hypothesis. It was found that upon performing this test, the grains were elongated, as seen in the images below. These elongated grains were due to some unknown cold-working, and resulted in giving us inflated results for the tests performed thus far. It is now known that we have to anneal the 1018 CRS specimens to match the published data. The annealing type that was chosen is Full Annealing, because that should bring the results to that of the published data within 3-4% as we expect, by getting the grains back to normal.


The purpose of this test is to verify the grain structure of a material. Depending on the contents of a material the metallurgical test will help validate the previously done Spark Test and Combustion test and our hypothesis.

Procedure

A sample from one of the specimens was cut and polished to a fine, 1 micron grit. Once polished the sample was cleaned in alcohol. After the alcohol had dried off the polished surface of the sample was treated with acid and then drowned in flowing water. This helped dilute the acid and the sample was then safe to touch with human hands. The sample was then observed under a high magnification microscope. The microscope helped determine the grain structure clearly. The images taken by a camera capable of taking such pictures was then compared to published data.



Data/Images Collected



Published Image for 1018 CRS Collected Image for 1018 CRS

Collected Images of Grain Structure under microscope



Error Analysis

The possibilities of errors in visually determining the accuracy of images is difficult. The abilities of the camera used to take the photographs were mediocre. Under the microscope however the grain structure was clearer.

Conclusion

Though it is hard to photographically verify the images, it was visually conclusive that the specimen grain structure matched that of the published grain structure image close enough, but full annealing will now be performed.

Post-Annealed Metallography TestExecutive Summary

With the specimens being fully annealed, a metallurgy test was performed once again to examine their grain structures. We came to a decision that upon full annealing the 1018 CRS, the grain structure will become less elongated, thus giving it a lower Sut value, so that it would match out CTQ which is 65.3 ksi. With the annealed specimen, a fatigue, tensile, and hardness tests were performed all over again to compare the results of the pre annealed to that of the post annealed data. Finally a metallurgy test was also redone to compare grain structures, and we found that the grain structure was definitely less elongated than the pre annealed images.


The objective of this experiment was to determine if performing the full annealing resulted in the samples having a more "normal" grain structure. Non-elongated grain structure is the reason why our fatigue, tensile and hardness Sut results are more close to the published value.



Data/Images Collected

Axial grain structure under microscope

Lateral grain structure under microscope



Appendix J

AnnealingAnnealing is a process by which a treated or worked metal can be brought back to its original microstructure.

During rolling or cold drawing, the grain structure of steel is elongated, making the steel stronger and harder. Annealing is processes which, by heating steel, its grain structure can relax and return to its original form. This non-elongated structure is typically weaker and softer than the elongated structure caused by cold rolling or cold drawing.

The annealing process for bringing steel back to its original structure and properties involves heating and controlled cooling. In order to achieve the re-alignment of the grain structure in a full anneal, steel must be brought to 1200-1300 degrees Fahrenheit. After a short period of time, the steel must be cooled slowly to avoid a quenching effect, usually taking approximately 15 hours.



Appendix K

Cost AnalysisEnergy Cost

Machine/ Experiment

Run Time (Hr.)

Power Usage

(watts) KwhCost

($0.15/Kwh)Fatigue 25 1000 25 $3.75Tensile 2 200 0.4 $0.06

Hardness 1 750 0.75 $0.11Annealing 12 5000 60 $9.00

Grinder 0.5 500 0.25 $0.04Computer 50 270 13.5 $2.03Metallurgy 1 2000 2 $0.30

Total 91.5 9720 101.9 $15.29

Testing

Group Technicians Hours Wage Labor/Cost

Group 1 Section 2 41.5 $16 $664

External CostIMR $60

Material $20Printing $40

EngineeringEngineers Hours/Eng Wage/Eng. Labor/Cost

7 50 $26 $9,100

Total Cost of Project

$9,914.00

Conclusion

This #’s were derived through estimation and online information. This is a small representation of what this project would cost in industry.



Appendix L

Green Belt Tools

Project CharterPROJECT NO.: 20111-0610403-GRO1

Start Date September 7, 2011 Completion Date November 9, 2011

Belt Name Duane Beck Champion William Leonard

Element Description Team Charter

Objective Statement

What is the objective to be achieved?

To determine the fatigue characteristics of AISI 1018 cold rolled steel and compare them to the published values by November 7, 2011.

Project

Scope

Which part of the process will be investigated? To determine the fatigue characteristics of AISI 1018

CRS.

Team Members

Who is on the team, internal and external personnel? Internal: Rahat Kamal, David Schmidt, Andrew Smith,

Kyle Manchester, Elijah Romulus, O’Neil Campbell, and Jeremy Ayala

External: Mike Caldwell and William Leonard

Project

Schedule

What is the projected timeline for each phase of the project? Please Refer to Gantt Chart



(Gantt Chart)

Project Summaryfor the Green Belt in MET

Stages / Phases

Goals and Start Date Deliverable Outcomes Belt /Champion Approval Signatures And End Date

Stage 1

Define Phase

Stage 1

Measure Phase

Stage 2

Analyze Phase

Stage 3

Improve Phase

Stage 3

Control Phase

Stage 3

Written Report

Stage 3

Oral Defense



Gantt chart


Forming1

Team gets to know each other

Storming2

Conflict Resolution begins

Norming3

Team Starts to Form

Performing 4

Teams are effective

Adjourning5

Team breaks off to complete tasks


Stages of Team Development

Phase 1

The team was created and initial kick-off meeting was held. Taking the task at hand the group brainstormed ideas of how to split up the initial tasks. With the initial set of Fatigue testing the team has been formed.

Phase 2

The team became effective at completing the tasks at hand in a timely and orderly manner

Phase 3

The team broke into two smaller teams and was still able to perform and adjourn effectively as one big initial group.



PDCA

Supply Chain Plan Do Check Act

SupplierReceive CTQ

requirements from Engineer

Manufacture product to Engineer’s

specifications

Implement a random

sampling plan and quality assurance program

Provide a Certificate if

Analysis (C of A) with each shipment

PurchasingReceive CTQ

requirements from Engineer

Order 1018 CRS to Engineer’s specification

Establish Supplier Audit

Procedures

Specify a Certificate of

Analysis (C of A) must accompany

each shipment of 1018 CRS

Engineering

Design and Develop 1018

Annealed Product

Specification

Implement internal

inspection on incoming

shipments of 1018 CRS

Implement a random

sampling plan.Perform testing and analysis on samples of 1018

CRS

Verify against a C of A that

comes with each shipment.

Implement a Corrective

action plan for nonconformanc

e products.

CORRECTIVE ACTION PLAN FOR NON CONFORMANCE OF 1018 ANNEALED PRODUCTSIf the samples that are tested do not conform to product specifications, engineering takes the following actions:

1) Engineering completes a non-conformance report with data analysis results.2) Engineering notifies purchasing with a non-conformance report with the data

analysis results.3) Purchasing notifies the Supplier of non-conformance report and results4) Supplier investigates the non-conformance5) Supplier responds to purchasing with a specified period of time6) Purchasing notifies engineering for Supplier’s actions7) Engineering enters non-conformance, data analysis, supplier correspondence and

outcome in records control system.



Process Flow Chart


Fati

gue

Tes

tin

g P

roce

du

re


High Level SIPOC



Box Plot Statistics on Testing

Pre- Annealed Sut Post Annealed Sut

Published Data hrb

Pre- Anneal Tensile

Pre- Anneal Tensile (From HRB)

Pre- Anneal Fatigue hrb

Post- Anneal Tensile

Post- Anneal Tensile (From HRB)

Post- Anneal Fatigue

63.5 95.8 105.9 99.5 66.4 60.9 62.3 63.2 67.591.1 94.3 94.6 67.0 32.1 61.8 33.391.4 96.3 94.9 73.9 45.7 61.9 47.491.4 104.9 94.9 79.2 50.0 62.5 51.991.9 95.4 82.4 50.3 62.5 52.291.9 95.4 84.2 51.4 53.492.0 95.5 85.3 51.5 53.592.1 95.6 86.6 51.6 53.692.4 95.9 164.4 52.8 54.895.4 99.0 53.1 55.196.2 99.9 53.6 55.696.2 99.9 55.3 57.497.9 101.6 56.8 59.098.2 101.9 57.0 59.298.3 102.0 57.3 59.598.4 102.2 59.9 62.2

60.0 62.360.5 62.860.6 62.961.5 63.861.9 64.362.0 64.462.0 64.462.1 64.563.1 65.5



Real: Published HRB Pre-A Ten Pre-A Hard Pre-A Fat

HRB A Ten A Hard A Fatigue

Min 63.5 91.1 94.3 94.6 66.4 32.1 61.8 33.3 67.5Q1 91.9 95.8 95.4 73.9 51.6 61.9 53.6 67.5Med 93.9 100.6 97.5 82.4 57.0 62.3 59.2 67.5Q3 96.6 105.2 100.3 85.3 60.9 62.5 63.2 67.5Max 98.4 105.9 102.2 164.4 63.1 62.5 65.5 67.5Mean 94.4 100.4 98.0 87.7 55.7 62.2 57.8

All units in KSI

Published Pre-A Ten Pre-A Hard Pre-A Fat A Ten A Hard A Fatigue0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

1018 CRS Comparative Box Plot



Two Sample T-Test: Non Annealed/AnnealedWith a 95% confidence our null hypothesis for the report was that if each team was distributed the same 1018 Cold Rolled Steel, then all samples distributed should be within the range of the published tensile strength. For most groups this null hypothesis was accepted, but our results gave us a smaller variance from the published results. This smaller variance resulted in a low two tail P value.

Sample # UTS (ksi) Group # Grp 1 S2 Published1 62.3

Group 1 Sec 2

62.3 63.42 61.8 61.8 63.43 61.7 61.7 63.44 62.5 62.5 63.45 62.5 62.5 63.46 61.8

Group 6 Sec 1

7 62.98 62.69 61

10 61.1

Group 4 Sec 1

11 61.812 62.713 62.214 63.915 61

Group 3 Sec 1

16 63.117 59.518 60.919 62.5

Group 1 Sec 1

20 61.121 62.522 61.4

Avg= 61.945S= 1.07095



Grp 1 Sec2Published

Mean 62.16 63.4Variance 0.0148 0Observations 5 5Hypothesized Mean Difference 0df 4t stat -7.20735P(T<=t)one tail 0.000982t critical one tail 2.131847P(T<=t)two tail 0.001965t critical two tail 2.776445

Ho:u1=upHa:u1 does not equal

Since the p value is less than 0.05, then we reject the null hypothesis

There are some factors that we have to take into account to determine why our P value was so much smaller than that of other groups. There is nothing that we found that directly caused such a low P value, but there had to be some kind of discrepancy with the data collected among the four tests.



ANOVAAn anova calculation is an analysis of variance between multiple groups of data to determine the statistical significance between the means of these groups. The data below was accumulated from 9 different groups preforming the same experiment with the same set of 1018 cold rolled steel samples.

group 1 s1

grp3 s1

grp 1 s2

grp6 s1

grp4 s1 grp2 s2 grp7 s1 grp2 s1 gr5 s1

93.7 93 105.9 100.5 92.1 95.6 94.7 92.9 94.291.5 94 104..9 92 94.3 94.2 96.1 93.4 92.993.2 93.3 95.3 94.9 96.2 93.8 95.2 93.4 96.193.6 104.4 94.3 96.7 94.5 95.7 94.8 93.9 95.693.6 95.1 100.1 96 95.3 95 92

102.6 95.5 106.4 95.7 96.1 102.291 92.9 95 92.8 96.4 9394 101.1 97.8 94.4 96.5 93

90.6 93.6 94.7103 94.8

Anova:SingleFactor

Summary

Groups Count Sum Average Variance

Group 1 s1 10 946.8 94.6819.7995555

6

Grp3 s1 8 769.246 96.15618.1414976

4Grp1 s2 5 500.5 100.1 28.34

Grp6 s1 8 779.332 97.41719.2715022

9

Grp4 s1 4377.055

3 94.2642.77471427

6Grp2 s2 9 851.1 94.567 1.1225

Grp7 s1 10 954.3 95.430.56455555

6

Grp2 s1 8 753.87 94.23410.7498267

9Grp5 s1 4 378.8 94.7 2.08666667



ANOVASource of Variation

SS df MS F P-Value F crit

Between Groups 173.766 8 21.7211.8834709

620.080476

24 2.1056

Within Groups657.340

9 57 11.532

Total831.106

9 65

Ho: u1=u3=u1=u6=u4=u2=u7Ha: u1 does not=u3 does not =u1 does not= u6 does not=u4 does not=u2 does not=u7

If the p is < or =0.05, then reject the null hypothesisIf the p is > 0.05, then fail to reject the null hypothesis

After analyzing the data, we failed to reject the null hypothesis do to our calculated P value. Our P value was 0.08 which is larger than 0.05 cut off point for 95% confidence.



Cause and Effect Fatigue Diagram



Cause and Effect Material Diagram



C & E Checklist



Appendix M

Meeting NotesMeeting # 1Date: 9-15-2011

Tasks Gathered test samples Scheduled training with TA Took measurements of samples Discussed Project Plan

Questions How does the fillet affect the size ratio and the moment arm?

o It makes it stronger because if it were a 90 degree cut the stress concentration factor would be different.

Meeting # 2Date: 9-19-11

*Full Attendance*

Task Worked on S-N Diagram to determine testing loads Project Plan



Finished SN diagram with loads


Set a break time with TA Began gathering data from other groups Analyzed the discrepancies encountered from the first three tested parts.

-The last three parts tested were over the calculated S-N curve which draws other questions about the quality of the material given.




Assigned members to selected groups Distributed different sections of the lab report to certain members of the team. Analyzed the results from the most recent breaks.

-The fourth part that was tested, had a 157 N load applied and ran for 103,119 cycles taking close to 30 minutes to break.-The fifth part was loaded at 90 N for 3,853,055 cycles and did not fail.-Since the part greatly exceeded the curve calculated in the S-N diagram, the piece theoretically never would have failed


Finished SN diagram with loads Finished Rockwell Hardness testing on four different specimens Finished Tensile Testing of four different specimens

-All values were what we expected and gave us a new specified tensile strength for the specimens


On schedule for the report write up Finished the metallurgy test on two different specimens

-One longitudinally and one transversely Got approval for the testing of annealed samples

Meeting #9Date: 10-31-11

Tested 5 annealed specimens over the weekend-All 5 tested for fatigue & Tensile-During the Tensile test the graph results were misplaced but the number values were still recorded.

Hardness Testing completed on annealed specimens



References1) Norton, Robert L. Machine Design: an Integrated Approach. Boston: Prentice

Hall, 2011. Print.2) Hibbeler, R. C. Statics and Mechanics of Materials. Boston: Prentice Hall, 2011.

Print.3) Online Materials Information Resource - MatWeb.Web. 04 Nov. 2011.

http://www.matweb.com/.4) Published images provided by http://www.metallographic.com/5) ASTM Standard E9306) "Appendix 1—Rockwell/Brinell Hardness Conversion." Technical

Data.Kennametal.Web. 8 Nov. 2011. <http://www.kennametal.com/images/pdf/techRef/milling/rockwellBrindellHardnessConv.pdf>.

7) http://resources.schoolscience.co.uk/corus/16plus/steelch2pg3.html 8) http://www.substech.com/dokuwiki/doku.php?

id=annealing_and_stress_relief9) http://www.carbidedepot.com/formulas-hardness.htm 10)Failure Mechanics Section 1 (Group Data)


http://www.carbidedepot.com/formulas-hardness.htm

http://www.substech.com/dokuwiki/doku.php?id=annealing_and_stress_relief

http://www.substech.com/dokuwiki/doku.php?id=annealing_and_stress_relief

http://resources.schoolscience.co.uk/corus/16plus/steelch2pg3.html

http://www.metallographic.com/

http://www.matweb.com/

fatigue analysis report_ final

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