1、Designation: B851 04 (Reapproved 2009)Standard Specification forAutomated Controlled Shot Peening of Metallic ArticlesPrior to Nickel, Autocatalytic Nickel, or Chromium Plating,or as Final Finish1This standard is issued under the fixed designation B851; the number immediately following the designati
2、on indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requi
3、rements for auto-mated, controlled shot peening of metallic articles prior toelectrolytic or autocatalytic deposition of nickel or chromium,or as a final finish, using shot made of cast steel, conditionedcut wire, or ceramic media. The process is applicable to thosematerials on which test work has s
4、hown it to be beneficialwithin given intensity ranges. It is not suitable for brittlematerials. Hand peening and rotary flap peening are excludedspecifically.1.2 Shot peening induces residual compressive stresses inthe surface and near-surface layers of metallic articles, control-ling or limiting th
5、e reduction in fatigue properties that occursfrom nickel or chromium plating of the article, or the fatigueproperties of unplated articles.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to
6、 address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B183 Prac
7、tice for Preparation of Low-Carbon Steel forElectroplatingB242 Guide for Preparation of High-Carbon Steel for Elec-troplatingB320 Practice for Preparation of Iron Castings for Electro-platingB322 Guide for Cleaning Metals Prior to ElectroplatingB607 Specification for Autocatalytic Nickel Boron Coat-
8、ings for Engineering UseB650 Specification for Electrodeposited Engineering Chro-mium Coatings on Ferrous Substrates3B656 Guide for Autocatalytic (Electroless) Nickel-Phosphorus Deposition on Metals for Engineering Use(Discontinued 2000)4B689 Specification for Electroplated Engineering NickelCoating
9、sB733 Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on MetalE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE165 Practice for Liquid Penetrant Examination for GeneralIndustryE709 Guide for Magnetic Particle Testing2.2 Federal Standards:5QQ-N-290 Nickel Plat
10、ing (Electrodeposited)QQ-C-320 Chromium Plating (Electrodeposited)2.3 Military Standards:5MIL-S-851 Steel Grit, Shot, and Cut Wire Shot, and IronGrit and Shot Blast Cleaning and PeeningMIL-S-13165 Shot Peening of Metal PartsMIL-C-26074 Coating, Electroless NickelMIL-STD-45662 Calibration System Requ
11、irements2.4 SAE Standards:6SAE J441 Cut Steel Wire ShotSAE J442 Test Strip, Holder and Gage for Shot PeeningSEA J827 Cast Steel ShotSAE J1830 Size, Classification and Characteristics of Ce-ramic Shot for Peening3. Terminology3.1 Definitions:1This specification is under the jurisdiction of ASTM Commi
12、ttee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.02 on Pre Treatment.Current edition approved Sept. 1, 2009. Published December 2009. Originallyapproved in 1994. Discontinued January 2004 and reinstated in 2004 as B85104.Last previous edition approved in
13、 2004 as B85104. DOI: 10.1520/B0851-04R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Withdra
14、wn. The last approved version of this historical standard is referencedon www.astm.org.5Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.6Available from Society of Automotive Engineers, 400 Commonwealth Drive,Warrendale
15、, PA 15096.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 Almen stripUNS G10700 carbon steel specimensthat are used to calibrate the energy of a shot peening stream(see Fig. 1).3.1.2 Almen strip holding fixturea fixture for ho
16、ldingAlmen strips in suitable locations that represent the positionand angular orientation of the surfaces of a part where intensityis to be determined and verified (see Fig. 2).3.1.3 arc heightflat Almen strips, when subjected to astream of shot moving at an adequate velocity, bending in anarc corr
17、esponding to the amount of energy transmitted by theshot stream. The height of the curved arc measured inmillimeters is the arc height, measured by an Almen gage (seeFig. 3).3.1.4 automatic equipmentshot peening equipment inwhich parts, fixtures, nozzles, and peening parameters arepreset by hand or
18、by locating fixtures and verified by inspectionpersonnel. The peening time is monitored automatically, andthe air pressure or wheel speed is set manually.3.1.5 compressive stressescold working or stretching thesurface beyond the elastic limit by shot peening, creating alayer in compression below the
19、 surface. The depth of compres-sive stresses is measured by the crown of the dimple to thedepth.3.1.6 coveragethe extent of obliteration of the originalsurface by dimples produced by impact from individual shotparticles and expressed as a percentage. See Note 1.3.1.7 depth of compressive stresseswhe
20、re the stress pro-file passes through 0 stress.3.1.8 intensitytheAlmen strip arc height at saturation.Archeight is not termed intensity correctly unless saturation isachieved.3.1.9 liquid tracer systema liquid coating material bear-ing a pigment that fluoresces under an ultraviolet light andremoves
21、at a rate proportioned to peening coverage.3.1.10 microprocessor-controlled equipmentpeeningequipment that has nozzle holding fixtures and is computercontrolled for processing, monitoring, and documentation ofthe peening parameters critical to process certification.3.1.11 nozzle holding fixturea fix
22、ture that holds thenozzles at the required location, distance, and angle in a lockedposition during the peening operation.3.1.12 process interrupt parametersfor critical peeningoperations, parameters such as shot flow, air pressure, partFIG. 1 Almen Test SpecimenFIG. 2 Assembled Test Strip and Holde
23、rFIG. 3 Almen GageB851 04 (2009)2r/min, oscillation rate, and cycle time that must be monitoredwithin process requirements.3.1.13 saturationthe minimum duration of peening nec-essary to achieve the desired Almen intensity which, whendoubled, does not increase the Almen strip arc height by morethan 1
24、0 %.3.1.14 saturation curvea curve that plots peening time onthe Almen strip (abscissa) versus Almen strip arc height(ordinate) achieved for the peening time (see Fig. 4).3.1.15 surface obliterationthe condition of a peened sur-face in which 100 % of the surface has been dimpled with shotimpressions
25、.NOTE 1A100 % coverage is defined as that leaving unpeened 2 % orless of the original surface because the estimation of coverage of theimpressions is difficult when this is approximately 98 % of the totalsurface. The 100 % coverage is a theoretical limiting value. Hence, theterm complete coverage is
26、 preferred. Complete coverage usually requiresincreasing the base time, that is, the time of peening to reach 98 %coverage, by 15 to 20 %. Values of 200 %, 300 %, etc. are obtained bymultiplying this run time by 2, 3, etc.4. Ordering Information4.1 When ordering articles to be shot peened, the purch
27、asershall state the following:4.2 ASTM designation.4.3 Type, size, and hardness of shot to be used (see 6.1).4.4 Number and frequency of the determinations of shotsize and uniformity required, if other than those specified in8.1.1.4.5 Peening intensity to be used at each location (see 8.2).4.6 Numbe
28、r, frequency, and locations of Almen test speci-mens to be provided for intensity verification and monitoringof the process if other than those specified in 8.2, 8.2.1, and8.2.2.4.7 Areas on the part that are to be shot peened and those tobe protected from the peening (see 7.5).4.8 Whether magnetic
29、particle or penetrant inspection isrequired before peening (see 7.2).4.9 Amount (percent) of coverage required in the areas to bepeened. A complete coverage is the minimum requirement (see3.1.6 and 8.3).4.10 Method for measuring coverage (see 8.3.1).4.11 Type of equipment to be used, automated or co
30、mputer-monitored microprocessor (see 6.3 and X1.10-X1.12).4.12 Details of any post treatment such as corrosion protec-tion (see 9.5).4.13 Requirements of certification and test records, asspecified in Section 10.5. Significance and Use5.1 Shot peening is a process for cold working surfaces bybombard
31、ing the product with shot of a solid and sphericalnature propelled at a relatively high velocity. In general, shotpeening will increase the fatigue life of a product that is subjectto bending or torsional stress. It will improve resistance tostress corrosion cracking. It can be used to form parts or
32、 correcttheir shapes. See Appendix X1 for additional information.5.2 It is essential that the shot peening process parametersbe controlled rigidly to ensure repeatability from part to partand lot to lot.5.3 This specification covers techniques and methods nec-essary for proper control of the shot pe
33、ening process.6. Materials and Equipment6.1 Shot Material Composition:6.1.1 Cast SteelCast steel shot shall conform to therequirements of SAE J827.6.1.2 Cut WireCut wire shot shall be made from coldfinished, round wire, confirming to SAE J441.6.1.3 Ceramic ShotCeramic beads shall conform to thechemi
34、cal composition given in Table 1 and to SAE J1830.6.1.4 Shot Form and Shape:6.1.4.1 Cast SteelCast steel shot shall be spherical inshape and free of sharp edges, corners, and broken pieces. Itshall conform to the acceptable shapes given in Fig. 5. Thenumber of nonconforming shapes (see Fig. 6) shall
35、 not exceedthe values given in Table 2.6.1.4.2 Cut WireCut wire shot shall be spherical in shape.It shall be free of sharp edges, corners, and broken pieces. Thenumber of nonconforming shapes shall not exceed the valuesgiven in Table 2.6.1.4.3 Ceramic ShotCeramic shot shall be spherical inshape and
36、free of sharp edges, corners, and broken pieces. Thenumber of nonconforming shapes shall not exceed the valuesgiven in Table 2.6.1.5 HardnessThe hardness of the media shall exceedthat of the material to be processed.6.1.5.1 Cast SteelCast steel shot shall have a hardness ofHRc45 to HRc55. Special ha
37、rd cast steel shot shall be used onproducts harder than HRc50 and shall have a hardness of HRc55 to HRc65.6.1.5.2 Cut WireCut wire shot shall have a hardness equalto or greater than that given in Table 3.6.1.5.3 Ceramic ShotCeramic shot shall have a minimumhardness of 560 HV30(30 kgf).6.1.6 Size:(1)
38、 The size of the media shall be capable of producing therequired intensity in the required time.(2) If a peened surface contains a fillet, the nominal size ofthe shot shall not exceed one-half of the radius of the fillet.FIG. 4 Saturation CurveTABLE 1 Composition of Ceramic ShotZrO2,% SiO2,% Al2O3,%
39、 Fe2O3, % Free Iron, %SpecificGravity,g/cm360.070.0 28.033.0 10.0 max 0.1 max 0.1 max 3.603.95B851 04 (2009)3(3) If the shot must pass through an opening, such as a slot,to reach a peened surface the nominal diameter of the shot shallnot exceed one-fourth of the width or the diameter of theopening.6
40、.1.6.1 Cast SteelCast steel shot charged into a machineshall conform to the screen requirements given in Table 4 forthe nominal size selected. When a machine has a completelynew charge of cast steel shot, conditioning shall be conducted,to remove the oxide layers on the shots, by bombarding onto aha
41、rdened steel surface for a minimum of two passes. Condi-tioning may not be required if the addition to the chargealready in the machine is below 25 %. If the addition of over25 % is made to the charge, conditioning is required.6.1.6.2 Cut WireThe diameter of cut wire shot chargedinto a machine shall
42、 conform to the requirements given inTable 4. Cut wire shot shall conform to the requirements oflength and cumulative weight given in Table 5. It is mandatorythat only preconditioned cut wire shot be used.6.1.6.3 Ceramic ShotCeramic shot charged into the peen-ing machine shall conform to the screen
43、requirements of Table6.6.2 Almen Strips, Blocks, and Gages Almen strips,blocks, and gages used shall meet the requirements ofSAE J442.6.3 EquipmentShot peening shall be conducted in a ma-chine that is designed for the purpose, propels shot at highspeed against the product, moves the product through
44、the shotstream in a way that ensures complete and uniform peening,and screens the shot continuously to remove broken or defec-tive shot.7. Pre-Peening Treatment7.1 Prior OperationsAreas of parts to be shot peenedshall be within dimensional requirements before peening.Except as otherwise permitted, a
45、ll heat treatment, machining,and grinding shall be completed before shot peening. All filetsshall be formed, all burrs removed, and all sharp edges andcorners that require peening provided with sufficient radii priorto peening, in order to result in complete coverage without anydistortion, chipping,
46、 or rollover.7.2 Flaw and Crack TestingWhen required, magneticparticle, penetrant, ultrasonic, or other flaw or crack detectionprocesses shall be completed prior to peening. See Test MethodE165 and Guide E709.7.3 Corrosion and DamageParts shall not be peened ifthey show evidence of invasive corrosio
47、n or mechanicaldamage on the surface.7.4 CleaningCleaning prior to peening shall be accom-plished by vapor degreasing, solvent wiping, warm solventspray, or an acceptable water-base nonflammable product, asrequired, to remove all soils, scale, and coatings from thesurface areas to be peened. See Pra
48、ctices B183, B242, B320,and B322.7.5 MaskingSurfaces designated on the drawing to be freeof shot peening marks shall be masked or otherwise protectedfrom the shot stream or indirect impingement by shot.7.5.1 Suitable masking materials are adhesive tape, sheetrubber, etc. If adhesive tape is used, it
49、 shall be coated on oneface with adhesive, and when the tape is removed from thesurface it shall not show any evidence of corrosion or leave anyresidue on the surface. Areas not requiring peening and notrequired to be masked shall be considered optional.8. Procedure8.1 ShotShot charged into the peening machine shall beas specified by the purchaser and meet the requirements of 6.1for the particular type, size, and material required. Unlessotherwise specified, all shot shall be maintained in the machineso that it conforms to the requirements o
