INDEX

SUBJECT

SHOT PEENING AND THE ALMENTEST METHOD

I NTRO DUCTI ON

TOOLS AND EQUIPMENT FOR ADEMONSTRATION

WHERE TO PURCHASE TOOLS ANDACCESSORIES

FACTORS AFFECTING PERFORMANCE

COMPARISONS TO FREE SHOTPEENING

STEP-BY-STEP DEMONSTRATIONPROCEDURE

MAXIMUM OPERATING SPEEDS

APPENDIX

PAGE NUMBER

2

6

3

4

5

7

18

20

PAGE 1

SHOT PEENING

Peening of metals to improve their performance is an ancient metal work­ing practice that can be traced back to medieval blacksmiths who hammered swordsand armor to make them stronger. Peening is a cold working process that impartsa residual compressive stress into the surface. A part that has its surfacesin compressive stress will show a significant increase in fatigue performanceand will also be less susceptible to stress corrosion cracking.

Most modern peening is done by impacting the metal surface with caststeel shot which is propelled at moderately high speed by an air blast or acentrifugal wheel. In most design applications, the proper method to determinethe amount of peening necessary, is to peen the part and then subject it tofatigue testing. The problem that arises is how to determine how much coldworking has been done to the part so that once fatigue test data is available,the part can be manufactured to the same tolerances as the test samples. Amethod for such measurement was developed by Mr. J. O. Almen of the ResearchLaboratories Division of General Motors. It is called the Almen Scale of PeenIntensity and has been adopted by the Society of Automotive Engineers (SAE).This method measures the amount of curvature of a standardized steel test stripwhen peened on one side. The best method for establishing a shot peening soeci­fication is to peen fatigue specimans to various intensities by changing operatingparameters, taking Almen intensity readings at each set of conditions. Once thedesired performance properties are achieved from the fatigue studies, there is areference (i.e. the Almen intensity) that allows returning to the operatingparameters that produced the desired results. The Almen test can then be usedas an in-process manufacturing specification to insure the correct peeningintensity is produced on a day-to-day basis. An excellent book on the basics ofshot peening and the Almen test method is available from the WheelabratorCorporation, Mishawaka, Indiana.

PAGE 2

INTRODUCTION

The intent of -this bulletin is to simplify the procedure for conductingan in-part demonstration of this product. The peening time and R.P.M. chartshave -been simplified to cover the majority of conditions normally encountere(JFor conditions not covered, the appendix has complete saturation and holeconversion charts. For further assistance, please contact the IndustrialTrades BUilding Service and Cleaning Products sales representative throughyour local 3M Branch sales office. -

The 3M Brand Roto-Peen Flap Assemblies type TC-330 each consist of twoscientifically-designed polymeric flaps to which tungsten carbide shotparticles are bonded. The flaps are joined with a special bonding matrixwhich allows them to be easily used with the appropriate hardware. Theseunique peening products provide a method of precision peening with maximumportability and cleanliness. They are especially suited for in-servicerework, manufacturing repair of small areas and will effectively peenholes down to 1/2 inch (12.7mm) diameter.

The 3M Brand Roto-Peen Flap Assemblies type TC-330 are covered in milspecification numbers MIL-R-81841 (AS) and MIL-W-81840 (AS). In-housespecifications have also been established by boeing Aircraft Company,McDonnell Douglas, Lockheed, and others.

3M Brand Roto-Peen Flap Assemblies type TC-330 are supplied in threesizes to cover various applications, and mandrels for each flap size.

PAGE 3

These products utilize #330 tungsten carbide shot. The 1 in. x 3 in.flap is recommended for large, flat unobstructed areas. If increasedcoverage rate is desired, as many as five 1 in. x 2 in. flaps may be loadedon the #7211 mandrel. The 9/16 in. x 1-1/4 in. flap assembly may also beused on flat areas or to peen holes down to 3/4 in. diameter. The 9/16 in.x 1 in. flap assembly is recommended for holes 1/2 in. to 3/4 in. diameter.

Any of the flaps may be cut narrower with a scissors to peen confinedareas or to peen into areas with a radius down to 1/16 in. (1.6mm).

Some suggested applications are:

Stress control on aircraftlanding gear, wing structures, andengine supports. Also on helicopter rotor assemblies or anyapplication that requires peening after grinding.

- Peening of surfaces subject to stress corrosion

- Peen forming

- Peen straightening

Peening the heat affect zone on welds to improve fatigueperformance

The 3M Brand Magnetic Almen Strip Holder is an essential part of theRoto-Peen system. It makes possible the use of the precise, standardizedAlmen Strip Peening Intensity· Control System, with Roto-Peen products byeliminating the protruding hold-down screws found on the conventional AlmenStrip Holder. It also makes Almen strip measurements easier and allows theuse of one Almen strip for an entire saturation curve. This holder isavailable from your Industrial Building Service and Cleaning ProductsDivision sales representative.

~. .

PAGE 4

FACTORS AFFECTING PERFORMANCE

When using 3M Brand Roto-Peen Flap Assemblies, Type TC-330, there arethree factors which control the amount of peening (intensity).

The rotational speed of the flap

The length of time a given area is peened

The Roto-Peen flap deflection

The rotational speed controls the peening intensity. Increasing thespeed, increased the intensity. Decreasing the speed lowers the intensity.The scale used to measure peening intensity is called the Almen Scale. Itis the degree of curvature, measured in 1/1000 of an inch, a precision steeltest strip (Almen Strip) will bend under a given set of operating conditions.For applications requiring higher intensities, the Almen "C" strip is used.For lighter applications, the Almen "N" strip is used.

All intensity measurements must be made on a Type 2 Almen specimangauge. (See tools and accessories section for ordering information.)

Peeni ng time controls the coverage of a surface. Mos t specifi ca ti onsfor peening are stated to an Almen intensity at 98+% coverage. 98+% cover-age is referred to as "saturation", which means the entire surface is coveredwith peening impressions. Saturation is further defined as the point at whichdoubling the peening time produces less than a 15% increase in Almen intensity.

The height the Roto-Peen flap is positioned above the whole surface isthe third critical factor in product performance. The height above the worksurface controls flap deflection. The best results are achieved with maximumflap deflection. In operation, this point of maximum flap deflection is alsothe easiest and most comfortable to maintain. The mantrel and flap assemblyshould be held such that the mandrel does not quite touch the work piece. Ifthe assembly is run too high above the surface, an uncomfortable bounce orvibration will be felt in the tool. Refer to drawings in the appendix foradditional information.

To insure uniform coverage of the surface being peened, a circular oroscillating motion should be used as the entire area to be peened iscovered uniformly. Visually inspect the peened area with the aid of a 5Xto lOX magnifier to determine whether complete coverage has been achieved.Every portion of the original surface must be covered with peening impressions.Repeen any area which does not show full coverage.

PAGE 5

COMPARISONS TO FREE SHOT PEENING

The following graphs compare the fatique performance of 3M BrandRoto-Peen Type TC-330 Flap Assemol ies co conventional free shot peening. ,

PAGE 6

TOOLS AND EQUIPMENT NECESSARY FOR

A ROTO-PEEN TC-330 DEMONSTRATION

1. Supply of TC-330 Flaps. Five of each size is recommended.

2. Mandrels, to fit flaps being used.

3. 3M Brand magnetic Almen strip holder.

4. Almen Type 2 specimen gauge.

5. Almen strips Type A, at least 25.

6. Technical Service Bulletin, at least two copies.

7. Variable speed tool. If a "set-point"* variable speed tool is notavailable, then a strobe light tachometer must be used.

8. Stop wa tch

* Atool of this type is presently being tested by the Industrial TechnicalService group. If the tool proves to be viable, the Industrial TechnicalService group will publish a Field Bulletin with details.

PAGE 7

This section is a step-by-step procedure to conduct a Roto-PeenTC-330 demonstration.

To illustrate this procedure, the following examples of customerrequirements are used:

. FLAT SURFACE

12 Almen "A" intensity

Area to be peened is 2" x 2-1/4"

PEENING A HOLE

10 Almen "A" intensity

Hole diameter .75" x 1.25" deep

PAGE 8

STEP ONE

_Almen "A" intensity desired _

Examp1e 1"'2'-- _

CONVERT TO 3M HOLDER INTENSITY

ALMEN "A" I NTENS ITYDESIRED

3456789

10

S1314151617181920

3M HOLDER INTENSITY

34567

101214

G)1820222325262830

3M Holder Almen Intensity _

Example 17

Conversion is necessary because the 3M Brand Magnetic Almen Strip Holderallows the Almen Strip to bend more than does the conventional screwdown type Almen strip holder.

PAGE 9

STEP TWO

Detenni ne area to be peened.

1. If a flat surface. area is length times width.

2. If area to be peened is a hole. then area is equal to3.14 x the hole diameter x the hole depth.

Area to be peened: IN2 _

(Write it down)

Example: - Area to be peened

is 2" x 2-1/4" = 4.5 in2

An Almen test strip is 3" long X 3/4" wide and thus has an area of2.25 in2 . To achieve 98+% coverage (saturation) of an Almen striprequires a minimum peening time of u,o minutes.

PAGE 10

STEP THREE

,.- Determi ne wh ich f1 ap size to use -

A. If the area to be peened is flat with no restrictions,use a 1" x 2" TC-330 flap.

B. If peening a hole, use the 9/16" xl" TC-330 flap forholes from 1/2" to 3/4". Use the 9/16" x 1-1/4" TC-330flap for holes over 3/4" diameter.

C. If working in a restricted area, use which ever sizeflap fits the application. To get into narrow slotsor into radii dovin to 1/16", the TC-330 flaps may becut narrO\~er wi th a scissors.

Go to Step Four A for 9/16" x 1" and 9/16" x 1-1/4" flaps.

Go to Step Four B for 1" x 2" flap.

Example: For this application a 9/16" x 1-1/4" flap has beenselected.

PAGE 11

STEP FOUR A

DETERMINING CORRECT RPM FOR 9/16" X 1" AND 9/16" X 1-1/4" TC- 330 FLAP

Peening Time

3M INTENS lTV 120 180 240DESIRED SECONDS SECONDS SECONDS

9 2900 2700 2600

10 3200 3000 2900

12 3800 3500 3400

14 4300 4100 3900

15 4600 4300 4200

17 5100 4980 4700

18 5400 5100 4900

20 6000 5700 5500

22 6500 6200 6000

23 6800 6500 6300

25 7300 7000 6800

26 7600 7300 7000

28 8100 7800 7600

30 8700 8400 8100

(For actual sa turati on curves see Appendi x)

TOOL RPM:

Example: 5000 RPM

TIME:

Example: 120 Seconds

Verify that the time and RPM are correct by peeni ng an A1menstrip with the above conditions (see Step Six for procedure).Slight RPM changes may be necessary.

Note: The maximum operating speed of these f1aos is 15,000 RPM.

PAGE 12

STEP FOUR B

DETERMINING CORRECT RPM FOR 1" X 2" TC-330 FLAP

Peening Time

3M INTENS ITYDESIRED

120SECONDS

180SECONDS

240SECONDS

9 2000 1800 1800

10 2100 2000 1900

12 2400 2300 2200

14 2700 2500 2500

15 2800 2700 2600

17 3100 2900 2800

18 3200 3100 3000

20 3500 3300 3200

22 3800 3600 3500

23 3900 3700 3600

25 4200 4000 3900

26 4300 4200 4000

28 4600 4400 4300

30 4800 4700 4500

(For actual saturation curves see Appendi x)

TOOL RPM:

(Hri te it do~m)

TIME:

(Hrite it down)

Verify that th e time an d RPM are correct by peeni ng an A1men strip\'Iith the above conditions (see Step Six for procedure). SlightRPt1 changes may be necessary.

Note: The maximum operating speed of this flap is 6,000 RPM.

PAGE 13

STEP FIVE

DETERMINE TIME NEEDED ON WORK AREA -

Area to be peened: (from Step Two)

(I~rite it down)

- The area of an A1men strip is 2.25 in2

- Thus, the time needed to peen the area of workpiece is

Peeni ng time = Area to be peened X Time (from Step 4A or 48)2.25

In many cases, an A1men strip is used to demonstrate Roto-Peencapabilities. In that case, the peening time is taken directlyfrom the charts. If other than an A1men strip is used,

EXAMPLE:Peening time = Area to be peened X Time (from Step 4A or 48)

2.25

= 4,5 X 120 seconds2.25

Peening time = 240 seconds

PAGE 14

STEP SIX

HOW TO MAKE AN ALMEN INTENSITY READING

1.

2.

3.

4.

Place an unpeened A1men strip on the A1men gauge.

Turn the face of the gauge so that the dial reads O.

Place the side of the strip that contacts the gauge down on the3M A1men strip holder.

Peen the strip with the time and speed determined from thecharts.

Note: Be sure to run the TC-330 flap in the direction that tendsto push the A1men strip against the strip that is bonded tothe holder.

5. Place the unpeened side of the strip against the A1men gauge.

6. Read the A1men intensity.

7. Compare reading in Step 6 to desired A1men intensity, and, ifnecessary, make a speed adjustment to achieve the desired intensity.If a speed correction is necessary, repeat above procedure toverify that correct intensity is achieved.

Note;

1. The A1men strips must be clean, free of oil or grease to givereproducible results.

2. A new TC-330 flap should be broken-in by running for approximatelyone minute on a surface similar to that which is to be peened.

PAGE 15

STEP SEVEN

PEENING HOLES

Because operating a TC-330 flap in the 1.0. of a hole reducesthe free swing of the flap, it is necessary to increase thespeed to achieve the same peening intensity. The increase inspeed needed is dependent on the diameter of the hole andwhich TC-330 flap is being used.

Chart 7A converts the speeds for the 9/16" x 1" flap in holesfrom 1/2" (12.7mm) to 3/4" (19.lmm).

Chart 7B converts the speeds for the 9/16" x 1-1/4" flap inholes from 3/4" (19.lmm) to 1-1/4" (3l.8mm). No conversion,increase in speed, is necessary in holes larger than 1-1/4"(31. 8mm).

To use the charts, find the 3M Almen intensity desired andread across the chart to the column that includes the holediameter to be peened.

To determine the peening time, use the formula -

Hole Peening Time(Seconds)

EXAMPLE:

: Hole Dia. X 3.14 X Hole Depth X 1202.25

Hole Size : .75" Diameter X 1.25" Depth

Des i red 3MPeening Intensity: l4A (Equal to lOA on the standard

Almen strip holder)

Hole Peening Time = .75 X 3.14 X 1.25 X 120(Seconds) 2.25

Hole Peening Time = 157 seconds(Seconds)

Correct tool RPM, from Chart 7B, is 7700 RPM.

The proper operating conditions for this example are ­

Tool Speed = 7700 RPMTime = 157 Seconds

See the appendix for formulas to calculate operating parametersfor conditions not covered in Charts 7A and 7B.

PAGE 16:

CHART 7A

CONVERSION TABLE FOR .50" (12.7mm) TO .75" (19.1mm) DIAMETER

HOLES TO BE PEENED WITH THE 9/16" Xl" TC-330 FLAP'II

CORRECT RPM CORRECT RPM FOR 120 SECOND PEENING TIME FOR3M AL~1EN STD. ALMEN HOLES WITHIN THE DIAMETER RANGE SPECIFIED

FOR A FLATNTENSITY INTENSITY

AREA (120 sees) .50-.53 .54-.57 .58-.61 .62-.65 .66-.69 .70-.73 .74-.77

7 6 2400 6000 5400 4900 4500 4200 3900 37009 7 2900 7300 6600 6000 5500 5100 4700 4400

10 8 3200 8000 7200 6600 6100 5600 5200 490012 9 3800 9500 8600 7800 7200 6700 6200 580014 10 4300 10800 9700 8900 8100 7500 7000 660015 11 4600 11500 10400 9500 8700 8100 7500 700017 12 5100 12800 11500 10500 9700 8900 8300 780018 13 5400 13500 12200 11100 10200 9500 8800 820020 14 6000 15000 13600 12400 11400 10500 9800 910022 15 6500 - 14700 13400 12300 11400 10600 990023 16 6800 - - 14000 12900 11900 11100 1040025 17 7300 - - 15000 13800 12000 11900 1110026 18 7600 - - - 14400 13300 12400 1160028 19 8100 - - - - . 14200 13200 1230030 20 8700 - - - - - 14200 13300

DO NOT EXCEED 15,000 RPM WITH THE ROTO-PEEN 9/16" X 1" TC-330 FLAP ASSEMBL~

CHART 7B..

CONVERSION TABLE FOR. 75" (l9.1mm) TO 1.25" (31.8mm) DIAMETER

HOLES TO BE PEENED WITH THE 9/16" X 1-1/4" TC-330 FLAP

PAGE 17

3M ALMEN

[NTENSITY

79

10121415171820222325262830

CORRECT RPM CORRECT RPM FOR 120 SECOND PEENING TIME FOR HOLESSTD. ALMEN WITHIN THE DIAMETER RANGE SPECIFIED

FOR A FLATINTENSITY

AREA (120 sees) .75-.81 .82-.88 .89-.94 .95-1.00 1.01-1.06 1.07-1.12 1.13-1.18 1.19-1.25

6 2400 4300 3900 3500 3300 3100 2900 2700 25007 2900 5200 4700 4300 4000 3700 3500 3200 31008 3200 5800 5200 4700 4400 4100 3800 3600 34009 3800 6800 6200 5600 5200 4800 4500 4300 4000

10 4300 7700 7000 6300 5900 5500 5100 4800 450011 4600 8300 7400 6800 6300 5800 5500 5100 490012 5100 9200 8300 7500 7000 6500 6100 5700 540013 5400 9700 8700 7900 7400 6900 6400 6000 570014 6000 10800 9700 8800 8200 7600 7100 6700 630015 6500 11700 10500 9600 8900 8300 7700 7300 690016 6800 12200 11000 10000 9300 8600 8100 7600 720017 7300 13100 11800 10700 10000 9300 8700 8200 770018 7600 13700 12300 11200 10400 9700 9000 8500 800019 8100 14600 13100 11900 11000 10300 9600 9100 860020 8700 - 14100 12800 11900 11100 10400 9700 9200

DO NOT EXCEED 15,000 RPM WITH THE 9/16" X 1-1/4"ROTO-PEEN TC-330 FLAP ASSEMBLY.

PAGE 18

MAXIMUM OPERATING SPEEDS

FOR ROTa-PEEN TYPE TC-330

FLAP ASSEMBLIES

9/16" X 1" Flap

9/16" X 1-1/4" Flap

1" X 2" Flap

15,000 R.P.M.

15,000 R.P.M.

6,000 R.P.M.

PAGE 19

TOOLS AND ACCESSORIES FOR USEWITH 3M BRAND ROTO PEEN PRODUCTS

(THE FOLLOWING TOOLS AND ACCESSORIES HAVE BEEN FOUNDSATISFACTORY. HOWEVER, EQUIVALENTS MAY BE SUBSTITUTED.)

ROTO TEENPRODUCT

TC-33C9/16" x 1-1/4"& 9/lE" xl"

TC-33(" 1" x 2"& CS- 330 3-1/2"DIAMETER FLAPLmEEL

ALL T(-330

ALL T(-330

TOOL OR ACCESSORY

MINIATURE FLEXIBLESHAFT POWER TOOL

ROTARY AIR TOOL

AIR MOTOR SPEEDCONTROL

STROBE LIGHTTACHOMETER

PHOTO ELECTRICTACHOMETER

ALMEN SPEC IMANGAUGE

ALMEN TEST STRIP

MODEL

SERIES MMG-44AELECTRIC MOTOR

ROTARY FILENO. 8067-D-2

STANDARD DUTYPRESSURE REGULATORNO. 27220

STROBATIC NO. 1531

THUMB TACH NO. GD-69

TYPE 2, NO. 74155

TYPE A, NO. 74268

MANUFACTURER

THE FOREDOM ELECTRICCOMPANYBETHEL, CONNECTICUT

THE ARO CORPORATION400 ENTERPRISE STREETBRYAN, OHIO 43506

GENERAL RADIO COMPANYCONCORD, MASSACHUSETTS

HEATH COMPANYBENTON HARBOR, MICH.49022

WHEELABRATOR CORP.415 BYRKIT STREETMISHAWAHA, INDIANA46544

COMMENTS

MOST VERSATILETOOL FOR FLAPASSEMBLIES

MAXIMUM PORTA­BILITY, LOWCOST, KIT FORMONLY

PAGE 20

APPENDIX

PEENING INTENSITY (ALMEN A MILS)(STJlNDARD ALMEN STRIP HOLDER)

FIG. 1 - CORRELATION BETWEEN 3M ROTa PEENAND STANDARD ALMEN STRIP HOLDER

PAGE 21

30

28 (.7nm)

26

24 (.6nm)

22

20 (.5nm)

18

16 (.4nm)

14

12 (.3nm)

10

8 (.2nm)

64 (.lnm)

2

o

~:: :7000 RPM - A&B4000 RPM - c

6000 RPM - A&B3500 RPM - C

5000 RPM - A&B3000 RPM - C4000 RPM - A&B2500 RPM - C

3000 RPM - A&B2000 RPM - C

012345678PEENING TIME (MIN)

A = 9/161Xl" (14.3 X 25nm) FlAP ASSEMBLYB = 9116

1Xl-l/4" (14.3 X 31.8rnm) FlAP ASSEMBLY

C = 11X2" (25 X 50rnm) FLAP ASSEMBLY

PAGE 22

3132" (2. 4mrn)

f ,)J_:J ----

TMIlX. MIN.

FIG. 3 - FUIP DEFLECTION RANGE FOR 9/16" X 1" C14.3mrn X 25) FUIP ASSEMBLY

MIlX.

-L _3/16" (4.8nrn)-T

MIN.

FIG. 4 - FUIP DEFLECTION RANGE FOR 9/16" X 1-114" C14.3mrn X 31.8) FUIP ASSEMBLY

MlIX.

5/16" C7. 9mrn)

MIN.

+

FIG. 5 - FUIP DEFLECTION RANGE FOR 1" X 2" (25mrn X 50) FLAP ASSEMBLY

PAGE 23

PROCEDURE FOR DETERMINING SPEED OF 3M BRAND ROTO PEEN9/16" X 1-114" (14.3 X 31.8mn) FLAP ASSEMBLY WHEN

USED IN HOLES FROM 3/4 IN. - 1-1/4 IN. (19mm - 31.~) DIA.

1. USING ROTO PEEN ALMEN STRIP HOLDER PEENING INTENSITY} DETERMINE TOOLSPEED (SI) FOR FLAT SURFACES AND HOLES LARGER THftN 1-1/4 IN. Ol.8mn)

DIAMETER BY REFERRING TO FIG. 2.

2. DETERMINE EFFECTIVE FLAP RADIUS (R2) BY REFERRING TO FIG. 6 BELOW.

3. CALCULATE REQUIRED TOOL SPEED (S2) FOR HOLE SIZES BETWEEN 3/4 IN. (19mm)

AND 1-1/4 IN. 01. Smn) BY USING THE FOLLOWING EQUATION:20 S2 = (S 1) C18/32)/R2

.-<

'"~j

• r-­.:t.'-<0v

X3-.'-.0.... z

I v....~

xo

18

16

14

12

10 +--~!f

8

6

4

2

o+-+--+--I----+-+-+-t--t--t--+-+----i10 11 12 13 14 15 16 17 18 19 20 21 22

HOLE RADIUS - 1/32 IN. OR (NO. X O.78rmi>

FIG. 6 - CORRELATION BETWEEN EFFECTIVE 9/16" X 1-1/4" C14.3 X 31.8nm) ,FLAP ASSEMBLYRADIUS AND HOLE RADIUS.

PAGE 24

3.

PROCEDURE FOR DETERMINING SPEED OF 3M BRAND ROTO PEEN9/16" X 1" 04.3 X 25nrn) FlAP ASSEMBLY WHEN USED

IN HOLES FROM 1/2 IN. - 1-1/16 IN.(12.7nrn - 2nnm) DIA.

1. USING ROTO PEEN ALMEN STRIP HOLDER PEENING INTENSITY, DETERMINE TOOLSPEED (Sl) FOR FLAT SURFACES AND HOLES LARGER THAN 1-1/16 IN. (2nnm)

,DIAMETER BY REFERRING TO FIG. 2.

2. DETERMINE EFFECTIVE FlAP RADIUS (R2) BY REFERRING TO FIG. 7 BELOW.

CALCULATE REQUIRED TOOL SPEED (S2) FOR HOLE SIZES BETWEEN 1/2 IN. (12.nnm)AND 1-1/16 IN. (27nrn) BY USING THE FOLLOWING EQUATION:

S2 = (Sl) (15/32)/R2

1011 1213141516171.8

- 1/32 IN. OR (NO. X O.7Smm)

+--+--+--t---l~-+---t--+-_.-+---+---J

>- 20..J

~UJ

18U1

~

S 16u..A

~'"'14

.~.........'" · 12xC)",X. · 10.:to.... z'-''-'- 0:: 8""0x ·z 6u,'-<.-<, C'J

''''"', 4.....~ I.-<

~~ 2UJ.-<

~~ 0

6 7 8 9

HOLE RADIUS

FIG. 7 - CORRELATION BETWEEN EFFECTIVE 9/16" X I" (14.3 X 31.Smm) FLAP ASSEMBLYRADIUS AND HOLE RADIUS

PAGE 25

SUGGESTED PRODUCT APPLICATIONS:

STRESS CONTROL

LANDTNG GEAR ASSEMBLIESWING STRUCTURESHELICOPTER ROTOR HUB ASSEMBLIESJET ENGINE SUPPORT MEMBERSMANUFACTURING REPAIRPEENING AFTER GRINDINGPEENING BEFORE PLATING

CORROSION CONTROL

PEENING OF SURFACES SUBJECT TO STRESS CORROSION

MI SCELLANEOUS

PEEN STRAIGHTENINGPEEN FORMINGBOND TESTING

AU slatements, le<:hnicallnformatlon and recommendations contained herein are based on tests we believe to be reliable, but the accuracy or compretene" thereofls notguaranteed, ana the following Is made in lieu of all warrantles expressed or Implled: Sellers and manufacturers only ob!lgatlOf'l shall be 10 replace such quantity althe productproved 10 be defectlve. Neither seller nor manufacturer shall be liable for any injury, loss or damage. dIrect or conSe<luenllal, arising oul of the usa of or Inability to use the pro­duct. Before uSing. :.;5el snail determine the SUitability althe product for hiS own intended use and user assumes all risks and liability Whatsoever In connecllon thereWIth.

i'lo statement or fEiCcmmenoatlOn r,o! CCfll8,neo nerern snail have an,' lorce Qf elleet unless In an agreemen! srgr.eo oy ollicers Of seller and manufacturer.