Juergen

Fischer, Dustin Umland, Brian Trenbeath, Jennifer Vein, Jennie Jorgenson, Jessica Messer, Matthew Cavalli, Douglas Larson, Bryce Mitton

(Engineered Surfaces Center of the University of North Dakota, Grand Forks)

Ranko

Tudorovic, Damian Wilmot, Jarrod Schell, Ben Hoiland, John Rindt(Alion

Science and Technology, Grand Forks)

Chemically accelerated vibratory surface finishing

(CAVSF)

U.S. Army Corrosion Summit 2009Clearwater Beach, FL

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1. REPORT DATE FEB 2009 2. REPORT TYPE

3. DATES COVERED 00-00-2009 to 00-00-2009

4. TITLE AND SUBTITLE Chemically accelerated vibratory surface finishing (CAVSF)

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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of North Dakota,Engineered Surfaces Center,4201 James RayDrive,Grand Forks,ND,58202

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13. SUPPLEMENTARY NOTES 2009 U.S. Army Corrosion Summit, 3-5 Feb, Clearwater Beach, FL

14. ABSTRACT

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Report (SAR)

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

Engineered Surfaces Center -

ESC* About 3 years.* Director, 3 FT Engineers and expanding.* 2 PT Faculty.* 1 PT Technician & OA.* 6 PT Students

University of North Dakota -

UND* Founded in 1883 -

6 years before statehood.* 13,000 students in 193 fields of study.

School of Engineering and Mines -

SEM* 1889 made the Engineering College at UND.* Programs include: Chemical, Civil, Electrical,

Geological, and Mechanical Engineering.

Bac

kgro

und

Content

•

Introduction (Equipment –

General –

Test samples)•

Basics (Material removal –

Roughness changes –

Shear

stress removal –

Temperature increase –

Sample distribution –

Different media)

•

End-roughness and micro structure of different C-steels•

Material removal and roughness changes versus the amount of treatment solution in the bowl

•

Material removal and roughness changes versus pH•

Comparing the performance of a commercially available acid treatment solution with 0.5 M Ammonium bioxalate

solution

Large vibratory bowl with 1.16 m inner diameter and a dosing station in the background for continuous flow of

chemicals through the bowl

Large vibratory bowl with 1.16 m inner diameter and a dosing station in the background for continuous flow of

chemicals through the bowl

Small vibratory bowl with 0.28 m inner diameter filled with 4 kg of large ceramic media.

Typical Process:•

2 hours acid treatment•

15 minutes water rinse•

2 hours burnishing

Typical Result:•

The average surface roughness of for example helicopter gear teeth goes down from 16 to 2 micro-

inches without impairing the geometry –

less than 200 micro-inches removed.

Benefits: Less friction and stress at the mating surfaces

resulting in•

No run-in time•

Lower operation temperature•

300 to 400 % longer fatigue lifetime

•

Reduced downtime•

Less noise, less vibration•

Higher energy efficiency•

Lower weight in new designs•

Overall lower costs

Chemically accelerated vibratory surface finishing (CAVSF)

Visual appearance of strip steel test pieces during the CAVSF process.0-120 minutes = acid treatment

120-135 minutes = water rinse135-260 minutes = burnishing

Material removal on Pyrowear 53™ during different processes versus time.

0

50

100

150

200

250

0 20 40 60 80 100 120 140 160

Time (minutes)

Mat

eria

l rem

oval

(

mic

ro-in

ches

)CAVSF with continues flow of Microsurface™ 5132and large ceramic media.

VSF dry.

CAVSF with water.

Etching with Microsurface™ 5132 in the beaker without rubbing ceramic media.

Material removal on strip steel during the super-finishing process

0

50

100

150

200

250

300

350

0 50 100 150 200 250

Time minutes

Rem

oved

mat

eria

l m

icro

-inch

es

Acid time

Water rinse Burnishing time

1.16 m diameter bowl

Roughness removed!100 micro-inches removed!

Material removal of strip steel pieces versus CAVSF time

Average roughness of strip steel pieces versus CAVSF time

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200 250Process time minutes

Ave

rage

roug

hnes

s m

icro

-inch

es

Acid time Burnishing timeWaterrinse

1.16 m diameter vibratory bowl

Around 5 micro-inchesafter acid time

Roughness removed!100 micro-inches removed!

Average roughness of strip steel pieces versus CAVSF time

Results of surface stress analysis by Bruker

As ground

After acid treatment

After CAVSF

σI and σII are the transformed stress values with all shear stress vanished.

The σI and σII indicates the distribution of the stress. The closer values means the stress is more equally distributed along each direction.

With the CAVSF, the shear stress was removed and the distribution of compressive stress becomes much more uniform.

15

20

25

30

35

40

45

50

0 50 100 150 200 250 300Run time (minutes)

Bul

k te

mpe

ratu

re o

f the

cer

amic

med

ia

(°C

)

Dry run

0.5 % water at start

1.5 % water at start

Running the 1.16 m diameter bowl at 1800 RPM with 230 kg brown ceramic media, no flow of chemicals and

closed noise protection lid under various conditions:

All the added water isevaporated at that point.Media is running dry

Media is still wet.

100 strip steel samples arranged for the distribution test

Starting the distribution test

Running the distribution test

Drawing of the media bulk in the 1.16 m bowl

0-45 deg.

45-90 deg.

90-135 deg

135-180 deg.180-225 deg.

225-270 deg.

270-315 deg.

315-360 deg.

Protrusion

Direction of the flow

Digging out the samples and measuring the location and orientation

Different media pieces

Material removal versus acid time with 0.27 M oxalic acid, 0.17 M ammonium oxalate and with different media.

0

10

20

30

40

50

60

0 20 40 60 80 100 120 140

Time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

LTW

STW

CW

LSW

LSW - saturatedsolutionBrown

LTW = large, triangular, whiteSTW = small, triangular, whiteCW = cylindrical, whiteLSW = lens shaped, cylindrical, whiteBrown = large, brown

Brown media (top side)

White media

Media characteristics

Media Bulk density

Max. liquid per load (2.2 L)

2/3 Max Area per load (2.2 L)Water thickness

Brown 1808 g/L 60 mL 40 mL 967877 mm2 41.3 µm

White Large Triangle 1746 g/L 53 mL 35 mL 1403172 mm2 24.9 µm

White Small Triangle 1622 g/L 100 mL 67 mL 2545960 mm2 26.3 µm

White Circular Cylinder 1584 g/L 104 mL 69 mL 2906367 mm2 23.7 µm

White Lens Cylinder 1726 g/L 72 mL 48 mL 1742464 mm2 27.5 µm

Cut Pyrowear 53™ sample with super-finished surface. The case hardened layer is smoother (Ra = 3 micro-inches (0.076 μm

)) than the substrate (Ra = 7 micro-inches (0.18 μm)). CAVSF reveals the

microstructure of the surface through etching.

Reasons for thermodynamic differences in the local etching rates

•

Components are unevenly distributed•

Crystal size may differ

•

Grain boundaries are different than the grain itself•

Failure in the crystal structure leads to tension in the lattice

•

Crystal structure (martensite

has a 1.7 kJ per mol higher free energy than ferrite)

•

Grains are often randomly oriented. Different lattice planes are exposed during cutting which creates atoms surrounded by 6 atoms or 4 atoms or …

•

Atoms in tips and edges of a crystal are only loosely connected.

Carbon steel test samples with different carbon contents and different heat treatments to create different hardnesses and a variety of grains (ferrite, cementite, pearlite, bainite, martensite, retained austenite …)

Carbon steel test samples with different carbon contents and different heat treatments to create different hardnesses

and a variety of grains (ferrite, cementite, pearlite, bainite, martensite, retained austenite …)

Used heat treatments:

As received (annealed)Air cooledCooled between platesCooled with wet towelsWater quenched (Wq)Wq

+ heat treatm. 1Wq

+ heat treatm. 2Wq

+ heat treatm. 3AnnealedAnnealed (diff. temp.)Heat treatment not defined

C 1020 C 1040 C 1050 C 1075 C 1095 Tested carbon steels

0

1

2

3

4

5

6

0 100 200 300 400 500 600 700 800 900

Hardness Hardness Vickers

Ave

rage

end

-rou

ghne

ss

mic

ro-in

ches

C 1020

C 1075

C 1095

C 1040

C 1050

Average end-roughness versus hardness for C-steels with different carbon contents and heat treatments.

Mechanism of the CAVSF

Originalsurface

roughness

Surface with conversion layer

Surface with conversion layer

Conversion layertops removed

Surface with conversion layer

Surface with conversion layer

Conversion layertops removed

Conversion layertops removed

(1) 2 H+(aq)

+ Fe(s) Fe++(aq) + H2(g)

(2) Fe++(aq)

+ 2 H2

O Fe(OH)2(s) + 2 H+(aq)

(3) 4 Fe++(aq)

+ O2

+ 2 H2

O 4 Fe+++(aq) + 4 OH-

(4) 3 Fe++(aq)

+ 3 (COOH)2(aq) 3 Fe(COO)2(s) + 6 H+(aq)

(5) 2 Fe+++(aq)

+ Fe(s) 3 Fe++(aq)

(4+5) 2 Fe+++(aq)

+ Fe(s)

+ 3 (COOH)2(aq) 3 Fe(COO)2(s) + 6 H+(aq)

Possible chemical reactions during acid treatment

Potential –

pH equilibrium diagram

System:Iron –

Waterat 25 deg. C(considering

as solid substances only

Fe, Fe(OH)2, and Fe(OH)3)

From M. Pourbaix

and N. de Zoubov

Material removal versus acid time for different amounts of pyrophosphoric

acid.

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80 100 120 140Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

60 mL

40 mL

20 mL

10 mL

Amount of pyrophoric acid based treatment solution in the 11" vibratory bowl with 4 kg large ceramic media:

Average roughness versus acid time for different amounts of pyrophosphoric

acid.

0

5

10

15

20

0 20 40 60 80 100 120 140

Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

)

60 mL

40 mL

20 mL

10 mL

Amount of pyrophoric acid based treatment solution in the 11" vibratory bowl with 4 kg large ceramic media:

Material removal versus acid time for different amounts of oxalic acid.

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80 100 120 140 160

Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

10 mL20 mL40 mL 40 mL

5 mL

60 mL

Amount of oxalic acid based treatment solution in the 11" bowl with 4 kg large ceramic media:

Average roughness versus acid time for different amounts of oxalic acid.

0

5

10

15

20

25

0 20 40 60 80 100 120 140 160

Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

)

10 mL 5 mL

20 mL60 mL40 mL40 mL

Amount of oxalic acid based treatment solution in the 11" bowl with 4 kg large ceramic media:

Material removal versus acid time for 0.2 M sodium bisulfate, 0.2 M iron (II), 0.2 M iron (III) (sulfate based).

0

50

100

150

200

250

300

350

0 20 40 60 80 100 120 140

Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

30 mL

40 mL

60 mL

90 mL

20 mL

15 mL

Amount of acid treatment solution in the 0.28 m bowl with 4 kg large ceramic media:

Average roughness versus acid time for 0.2 M sodium bisulfate, 0.2 M iron (II), 0.2 M iron (III) (sulfate based).

0

5

10

15

20

25

0 20 40 60 80 100 120 140

Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

)

30 mL

40 mL

60 mL

90 mL

20 mL

15 mL

Amount of acid treatment solution in the 0.28 m bowl with 4 kg large ceramic media:

Material removal versus acid time for various amounts of a solution containing 0.27 M oxalic acid, 0.17 M

ammonium oxalate

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

20 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

60 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

40 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

.

Average roughness versus acid time for various amounts of a solution containing 0.27 M oxalic

acid, 0.17 M ammonium oxalate

0

2

4

6

8

10

12

14

16

18

20

0 20 40 60 80 100 120 140Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

) 20 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

60 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

40 mL 0.27M (COOH)2, 0.17M (NH4)2(COO)2

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6

Starting pH

Mat

eria

l rem

oval

(m

icro

-inch

es)

20 mL Microsurface™ 5401

20 mL water

20 mL 0.35 M NaHCO3

20 mL 1.05 M NaHCO3

20 mL 0.70 M NaHCO3

All solutions contain 20 mL Microsurface™ 5401 plus the solution mentioned

20 mL 0.525 M NaHCO3

Material removal versus starting pH for different mixtures of oxalic acid based treatment solutions.

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5 6

Starting pH

Ave

rage

end

roug

hnes

s (

mic

ro-in

ches

)

All solutions contain 20 mL Microsurface™ 5401 plus the solution mentioned

20 mL Microsurface™ 5401

20 mL water20 mL 0.35 M NaHCO3

20 mL 0.525 M NaHCO3

20 mL 0.7 M NaHCO3

20 mL 1.05 M NaHCO3

Average roughness versus starting pH for different mixtures of oxalic acid based treatment solutions.

Material removal versus acid time for ammonium oxalate solutions with oxalic acid.

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80 100 120 140

Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

0.3 M (NH4)2(COO)2

0.14 M (COOH)2, 0.34 M (NH4)2(COO)2

0.20 M (COOH)2, 0.34 M (NH4)2(COO)2

Average roughness versus acid time for ammonium oxalate solutions with oxalic acid.

0

2

4

6

8

10

12

14

16

18

20

0 20 40 60 80 100 120 140

Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

)

0.34 M (NH4)2(COO)20.14 M (COOH)2, 0.34 M (NH4)2(COO)20.2 M (COOH)2, 0.34 M (NH4)2(COO)2

Material removal versus starting pH for 0.34 M ammonium oxalate solutions with oxalic acid.

0

10

20

30

40

50

60

70

80

90

100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Starting pH

Mat

eria

l rem

oval

afte

r 2 h

ours

(m

icro

-inch

es)

Average end roughness versus starting pH for 0.34 M ammonium oxalate solutions with oxalic acid.

0

2

4

6

8

10

12

14

16

18

20

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Starting pH

Ave

rage

roug

hnes

s af

ter 2

hou

rs a

cid

trea

tmen

t (m

icro

-inch

es)

Material removed from strip steel samples vs. acid time for different sodium bisulfate solutions.

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140

Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

0.15 M NaHSO4pH = 1.42 (pink)

0.1 M NaHSO4 pH = 1.49 (red)

0.05 M NaHSO4pH = 1.70 (blue)

Average roughness of strip steel samples vs. acid time for different sodium bisulfate solutions.

0

5

10

15

20

25

0 20 40 60 80 100 120 140Acid time (minutes)

Ave

rage

roug

hnes

s (m

icro

-inch

es)

0.15 M NaHSO4pH = 1.42 (pink)

0.1 M NaHSO4 pH = 1.49 (red)

0.05 M NaHSO4pH = 1.70 (blue)

Material removed from strip steel samples vs. acid time for different buffered sodium bisulfate solutions.

0

20

40

60

80

100

120

140

0 50 100 150 200Acid time (minutes)

Mat

eria

l rem

oval

(m

icro

-inch

es)

0.25 M (NH4)2SO4, 0.175 M NaHSO40.25 M (NH4)2SO4, 0.125M NaHSO40.75 M (NH4)2SO4, 0.125 M NaHSO40.75 M (NH4)2SO4, 0.175 M NaHSO40.5 M (NH4)2SO4, 0.15 M NaHSO4

Average roughness of strip steel samples vs. acid time for different buffered sodium bisulfate solutions.

0

2

4

6

8

10

12

14

16

18

20

0 20 40 60 80 100 120 140 160 180 200Acid time (minutes)

Ave

rage

roug

hnes

s (

mic

ro-in

ches

) 0.25 M (NH4)2SO4, 0.175 M NaHSO40.25 M (NH4)2SO4, 0.125 M NaHSO40.75 M (NH4)2SO4, 0.125 M NaHSO40.75 M (NH4)2SO4, 0.175 M NaHSO40.5 M (NH4)2SO4, 0.15 M NaHSO4

Average roughness after 2 h acid treatment vs. starting pH of the acid.

0

5

10

15

20

25

1 1.2 1.4 1.6 1.8 2 2.2 2.4Starting pH

2 h

aver

age

roug

hnes

s (

mic

ro-in

ches

)

NaHSO4

NaHSO4 and(NH4)2SO4

Material removal versus acid time in the 0.28 m vibrating bowl

0

5

10

15

20

25

30

35

40

45

50

0 20 40 60 80 100 120 140

Acid Time (minutes)

Mat

eria

l Rem

oval

(mic

ro-in

ches

)

Microsurface™ 54010.531 M Ammonium Bioxalate

Averaged curves with standard deviations from 5 runs

Average roughness versus acid time in the 0.28 m vibrating bowl

0123456789

1011121314151617181920

0 20 40 60 80 100 120 140

Acid Time (minutes)

Ave

rage

Rou

nghe

ss (m

icro

-inch

es)

Microsurface™ 54010.531 M Ammonium Bioxalate

Averaged curves with standard deviations from 5 runs

AcknowledgementsThis project is sponsored by the Defense

Technical Information Center. The work was made possible by the contractual relationship between AMMTIAC and DoD

to research and

analysis of advanced materials. This includes US Army Benét

Laboratories with US Army

ARDEC (Armament Research, Development and Engineering Center).

US Army Benét

Laboratories, Alion

Science and Technology, and the Engineered Surfaces Center of the University of North Dakota are working together in improving life and performance

of materials used for weapons systems.

Thank you for your attention!

U.S. Army Corrosion Summit 2009Clearwater Beach, FL

Questions?

Email: JuergenFischer@mail.und.eduPhone: 701-757-5144

mailto:JuergenFischer@mail.und.edu

Slide Number 1Slide Number 2ContentLarge vibratory bowl with 1.16 m inner diameter and a dosing station in the background for continuous flow of chemicals through the bowlSlide Number 5Chemically accelerated vibratory �surface finishing (CAVSF)Slide Number 7Slide Number 8Slide Number 9Slide Number 10Results of surface stress analysis by Bruker Slide Number 12100 strip steel samples arranged for the distribution testStarting the distribution testRunning the distribution testDrawing of the media bulk in the 1.16 m bowlDigging out the samples and measuring the location and orientation Different media piecesMaterial removal versus acid time with 0.27 M oxalic acid, �0.17 M ammonium oxalate and with different media.Slide Number 20Media characteristicsCut Pyrowear 53™ sample with super-finished surface. The case hardened layer is smoother (Ra = 3 micro-inches (0.076 μm )) than the substrate (Ra = 7 micro-inches (0.18 μm)). CAVSF reveals the microstructure of the surface through etching.�Reasons for thermodynamic differences in the local etching ratesCarbon steel test samples with different carbon contents and different heat treatments to create different hardnesses and a variety of grains (ferrite, cementite, pearlite, bainite, martensite, retained austenite …)Slide Number 25Mechanism of the CAVSF�Possible chemical reactions during acid treatmentPotential – pH equilibrium diagramMaterial removal versus acid time for different amounts of pyrophosphoric acid.Average roughness versus acid time for different amounts of pyrophosphoric acid.Material removal versus acid time for different amounts of oxalic acid.Average roughness versus acid time for different amounts of oxalic acid.Material removal versus acid time for 0.2 M sodium bisulfate, 0.2 M iron (II), 0.2 M iron (III) (sulfate based).Average roughness versus acid time for 0.2 M sodium bisulfate, 0.2 M iron (II), 0.2 M iron (III) (sulfate based).Material removal versus acid time for various amounts of a solution containing 0.27 M oxalic acid, 0.17 M ammonium oxalate�Average roughness versus acid time for various amounts of a solution containing 0.27 M oxalic acid, 0.17 M ammonium oxalateMaterial removal versus starting pH for different mixtures of oxalic acid based treatment solutions.Average roughness versus starting pH for different mixtures of oxalic acid based treatment solutions.Material removal versus acid time for ammonium oxalate solutions with oxalic acid.Average roughness versus acid time for ammonium oxalate solutions with oxalic acid. Material removal versus starting pH for 0.34 M ammonium oxalate solutions with oxalic acid.Average end roughness versus starting pH for �0.34 M ammonium oxalate solutions with oxalic acid.Material removed from strip steel samples vs. acid time for different sodium bisulfate solutions.Average roughness of strip steel samples vs. acid time for different sodium bisulfate solutions.Material removed from strip steel samples vs. acid time for different buffered sodium bisulfate solutions.Average roughness of strip steel samples vs. acid time for different buffered sodium bisulfate solutions.Average roughness after 2 h acid treatment �vs. starting pH of the acid.Material removal versus acid time �in the 0.28 m vibrating bowlAverage roughness versus acid time�in the 0.28 m vibrating bowlAcknowledgementsThank you for your attention!