1、Designation: B851 04 (Reapproved 2014)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 forautomated, 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 sho
4、wn 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 the
5、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 a
6、ddress 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 Practi
7、ce 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 Coating
8、sfor Engineering UseB650 Specification for Electrodeposited Engineering Chro-mium Coatings on Ferrous SubstratesB656 Guide for Autocatalytic (Electroless) Nickel-Phosphorus Deposition on Metals for Engineering Use(Discontinued 2000) (Withdrawn 2000)3B689 Specification for Electroplated Engineering N
9、ickelCoatingsB733 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:4QQ-N-290
10、 Nickel Plating (Electrodeposited)QQ-C-320 Chromium Plating (Electrodeposited)2.3 Military Standards:4MIL-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
11、 System Requirements2.4 SAE Standards:5SAE 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 Peening1This specification is under the jurisdiction of ASTM Committee B08 onMetalli
12、c and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.02 on Pre Treatment.Current edition approved Nov. 1, 2014. Published November 2014. Originallyapproved in 1994. Discontinued January 2004 and reinstated in 2004 as B85104.Last previous edition approved in 2009 as B85109. DO
13、I: 10.1520/B0851-04R14.2For 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.3The last approved version of this his
14、torical standard is referenced onwww.astm.org.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.5Available from Society of Automotive Engineers, 400 Commonwealth Drive,Warrendale, PA 15096.Copyright ASTM International,
15、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions: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 holdingAlmen s
16、trips 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 corresponding to
17、 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 by locating
18、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 surface. Th
19、e 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 stresseswhere the stres
20、s profilepasses 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 bearinga pigment that fluoresces under an ultraviolet light and removesat a rate propor
21、tioned to peening coverage.3.1.10 microprocessor-controlled equipmentpeeningequipment that has nozzle holding fixtures and is computerFIG. 1 Almen Test SpecimenFIG. 2 Assembled Test Strip and HolderFIG. 3 Almen GageB851 04 (2014)2controlled for processing, monitoring, and documentation ofthe peening
22、 parameters critical to process certification.3.1.11 nozzle holding fixturea fixture 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, a
23、ir pressure, partr/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 10 %.3.1.14 satur
24、ation 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.NOTE 1A100 % co
25、verage 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 preferred. Comp
26、lete 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 purchasershall state
27、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 Number, frequency, an
28、d 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 particle or pene
29、trant 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 computer-monitored
30、 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 bybombarding the product
31、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 correcttheir sh
32、apes. 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 peening process.6.
33、 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 thechemical composition
34、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 not exceedthe v
35、alues 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 free of sharp ed
36、ges, corners, and broken pieces. Thenumber of nonconforming shapes shall not exceed the valuesgiven in Table 2.FIG. 4 Saturation CurveTABLE 1 Composition of Ceramic ShotZrO2,% SiO2,% Al2O3,% Fe2O3, % Free Iron, %SpecificGravity,g/cm360.070.0 28.033.0 10.0 max 0.1 max 0.1 max 3.603.95B851 04 (2014)36
37、.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 hard 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 wi
38、re 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) The size of the media shall be capable of producing therequired intensity in the required time.(2) If a peened surface contains
39、 a fillet, the nominal size ofthe shot shall not exceed one-half of the radius of the fillet.(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.6.1.6.1 Cast Stee
40、lCast 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 ahardened steel sur
41、face 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 conform to the
42、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 requirements of
43、Table6.6.2 Almen Strips, Blocks, and GagesAlmen strips, blocks,and gages used shall meet the requirements of SAE 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 the shotstream i
44、n 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, all heat treatmen
45、t, 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, or rollover.7.2
46、 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 corrosion or mechanicald
47、amage 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 Practices B183, B24
48、2, B320,and B322.FIG. 5 Acceptable ShapesFIG. 6 Unacceptable ShapesTABLE 2 Maximum Allowable Nonconforming ShapesCastSteel, Cut Wire, and Ceramic Shot (in accordance with Fig. 6)Cast Steel Size Cut Wire Size Ceramic SizeMaximum AllowableNonconformingShapes per area1cm1cm930 5780 5660 CW62 12550 CW54
49、 12460 CW47 15390 CW41 80CW35 80330 CW32 Z850 80280 CW28 80230 CW23 Z600 80190 CW20 80170 Z425 80130 480110 Z300 64070 Z210 640TABLE 3 Hardness Cut Wire ShotCut Steel Wire Shot (Shall Have the Following Minimum Hardness)Shot Size Minimum Hardness, Rockwell CCW 62 36CW 54 39CW 47 41CW 41 42CW 35 44CW 32 45CW 28 46CW 23 and finer 48B851 04 (2014)47.5 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 mat
