welding eng lab guides
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weldingTRANSCRIPT
MEM661APPLIED WELDING
ENGINEERINGLAB GUIDELINE
Prepared by:
ASSOC PROF SUNHAJI KIYAI ABAS
Helped by: S Fairuz
Experiment 1
Title: Effect of change in polarity on Weld Penetration in SMAW & GTAW
SMAW GTAW PLATE 1 PLATE 2
Cut 1 for Group 1
Cut 2 for Group 2
Cut 3 for Group 3
Cut 4 for Group 4
Cut 5 for Group 5
Cut 6 for Group 6
D A D Pulsed TIG A DC C C C CR S SP P P
Weld on plate Weld on plate
Same current Same current
Same Weld Travel Speed Same Weld Travel Speed
Instruction to students:
1. Observe performance
2. Cut, polish, etch, observe, and redraw the macrostructure of the weld bead i.e. WM & HAZ.
3. Measure the depth of weld penetration due to polarity changes both in SMAW & GTAW.
4. Analyze & make comparison within SMAW, GTAW, and between SMAW & GTAW.
5. Discuss the findings.
6. Conclude the experiment.
Experiment 2
Title: Effect of different welding processes on hardness and depth of weld penetrations in GMAW
(MIG & MAG) & FCAW (shielded & unshielded)
GMAW FCAW
M M Shielded Unshielded I AG G
Weld on Plate
Same current
Same weld travel speed
Instruction to students:
1. Observe performance
2. Cut, polish, etch, observe, and redraw the macrostructure of the weld bead i.e. WM & HAZ.
3. Measure the depth of weld penetration due to changes in welding process both is GMAW & FCAW.
4. Measure the hardness on WM, HAZ and BM using Vickers method at points shown below.
MIG MAG Unshielded Shielded FCAW
B H W H B M A M A M
Z Z
5. Analyze and make comparison in performance.
6. Analyze and make comparison in depths of penetration.
7. Analyze and make comparison in hardness.
8. Discuss the findings.
9. Conclude the experiment.
Experiment 3
Title: Study the system operation and performance for SAW, SPOT/SEAM, & Friction welding.
SAW
1. Prepare 2 similar plates.
2. Weigh both plates
3. Run SAW on plate 1 using DCRP, record current and weld travel speed.
4. Run SAW on plate 2 using DCSP, use same current & weld speed as plate 1
5. Observe performance.
6. Analyze and make comparison in performance.
7. Calculate the Rate of Deposition in both polarities.
8. Analyze & make comparison in Rate of Deposition
9. Discuss the findings.
10. Conclude the experiment.
Plate 1 Plate 2
DCRP DCSP
Weld On Plate
SPOT / SEAM WELDING
1. Study SPOT welding / SEAM welding system operation.
2. Identify the welding variables and parameters involved in either or both cases.
3. Prepare tables suitable to be used when conducting SPOT & SEAM welding processes.
4. Find out how tests are conducted to analyze the quality of welds obtained in both processes.
SPOT weld nugget SEAM welded
Frictim Welding (FW)
1. Study FW system operation.
2. Identify the welding variables & parameters involved in FW
3. Prepare tables suitable to be used when conducting FW processes.
4. Find out how tests are conducted to analyze the quality of welds obtained in FW
Metal rod
Annular flash ring
Experiment 4
Title: Study the Science and System operation of thermal cutting using Gas Cutting, Plasma Cutting, and Air
Arc Gouging process.
Gas Cutting (Oxy-Cutting)
1. Find out the science of gas cutting using Oxy-cutting process.
2. Display the procedure of oxy-cutting on carbon steel.
3. Find out the oxygen ignition temperature for carbon steel & reactions involved.
4. Find out how analysis made to evaluate cut quality.
5. Do oxy-cutting on carbon steel & AL/SS.
6. Analyze results
7. What contributes to good cuts?
Plasma Cutting
1. How plasma is produced in Plasma Cutting Process.
2. Draw the system operation in Plasma Cutting and describe briefly.
3. Which type of Arc (Transferred Arc or Non Transferred Arc) suitable for Plasma Cutting?
4. Do plasma cutting in AL & SS.
5. What contributes to quality cuts?
6. What metals normally cut by Plasma Cutting.
Air Arc Gouging
1. Draw the system operation in Air arc gouging & describe briefly.
2. What is the difference between gouging and cutting?
3. When Air Arc gouging applied.
4. Describe the correct procedure in Air Arc Gouging
5. Do Air Arc gouging in DCRP & DCSP, compare & analyze their performance.
Experiment 5Title: Destructive Tests - Bend Test & Nick Break Test / Fracture Test to evaluate quality of weld on
Butt & Fillet welds.
Bend Test for Butt Weld
Preparation
Weld face Ground flush
X 2 plates
Weld root Ground flush
Face Band Test (FBT) 40mm
Weld Face
FBT
Root Band Test (RBT) Weld Root
RBT
Nick Break Test (NBT) for Butt Weld
1. Prepare specimen for NBT saw cut of depth 1.5 – 2.0 mm around center of weld
2. Cyclic / fatigue fracture using press machine.3. Observe & record internal defects such as porosity, slag inclusion, etc.4. Comment with reference to Standard Codes s.a. BS/AWS/ASME
Fracture Test (FT) for fillet weld
1. Do Single Fillet Weld on T-joint . 2. Cut & prepare specimen for FT using disc cutter or power saw.3. Measure leg length & throat4. Observe weld penetration 5. Saw cut centre of weld at face to a depth of 1.5 – 2.0 mm6. Do FT on Fillet Weld using Press Machine.7. Observe & record presence of internal defects s.a. porosity, slag inclusion, lack of root penetration,
lack of root fusion, etc.8. Comment with reference to Standard Codes s.a. BS/AWS/ASME
Throat
T-Joint Leg length
Leg length
Direction to cause fracture
Saw cut,
depth 1.5 -2.0 mm
General Question
Why and when do we need to conduct:
Face Bend Test?
Root Bend Test?
Side Bend Test?
Nick Break Test / Fracture Test?
Experiment 6
Title : Destructive Test - Strength Test & Toughness Test to evaluate quality of weld for Butt Welded Joint
Strength Test : Tensile Strength Test
1. Get sample of standard such as ASTM or BS to be used as reference to prepare specimen for Tensile
Strength Test.
R W R
D
B C
D
A A
L = Length of Specimen
2. Configure the test specimen above in detail as according to the selected applicable standard.
W = Weld width
D = Reduced section
A = Straight portion
R = Radius
L = Length of specimen (to suit machine)
B = Width of specimen (to suit machine)
C = Traverse length of weld
G = Gauge Length
G
T = Thickness of plate
3. Calculate the cross-sectional area at reduced section.
4. Do tensile test and record the yield stress value and UTS value.
5. Observe & record the location of fracture either on WM or BM
6. Obtain from relevant sources the value of yield stress (σ yield ) and UTS of base metal.
6. Calculate/record the % of elongation.
7. Give the meaning of the values obtained in [4] and the observation in [5] to comment on the quality of
weld produced as referred to a selected standard for acceptance.
Toughness Test : Charpy Impact Test
1. Get sample of standard such as ASTM or BS to be used as reference to prepare specimen for Charpy
Impact Test.
W
T
L
1. Configure in detail the above specimen for Charpy Impact Test as according to the requirement of the
applicable standard.
2. Do Charpy Impact Test and record the impact toughness value (I charpy)
D
Toughness Test : Izod Test
1. Get sample of standard such as ASTM or BS to be used as reference to prepare specimen for Izod
Test.
W S
T
L
2. Configure in detail the above specimen for Izod Test as according to the requirement of the
applicable standard code.
3. Do Izod test & record the impact toughness value (Iizod)
General Question
1. When do we need to do Charpy Impact Test or Izod Test?
2. Give the meaning of the impact toughness values obtained in both cases.
D
Experiment 7
Title: Obtaining chemical composition using Arc Spark Spectrometer
1. Describe the machine “Arc Spark Spectrometer”
2. What theoretical concept used to identify the elements and the percentages composition contents
in the metal matrix?
3. Prepare specimen for arc spark spectrometer test to identify the elements and respective
composition accurately.
I. Carbon steel
II. AL/SS
Weld padding (WM)
Base metal
Grind/machine flat for spectrometer test
Grind/machine flat for spectrometer test
4. On carbon steelI. Obtain the composition of BM
II. Obtain the composition on WMIII. Calculate the Carbon Equivalent (CE) of Base Metal and give meaning.IV. Compare the composition on Weld Metal (WM) with the composition found on Base Metal
(BM) and give meaning.
5. On AL/SS I. Find the composition of both Base Metal and Weld Metal and give comment
II. Which category the AL belongs?III. Which category the SS belongs?