【astm標(biāo)準(zhǔn)】b 851 - 04 (2014)

1、Designation: B851 ? 04 (Reapproved 2014)Standard Specification for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel, Autocatalytic Nickel, or Chromium Plating, or as Final Finish1This standard is is

2、sued under the fixed designation B851; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates th

3、e year of last reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for automated, controlled shot peening

4、of metallic articles prior to electrolytic or autocatalytic deposition of nickel or chromium, or as a final finish, using shot made of cast steel, conditioned cut wire, or ceramic media. The process is applicable to thos

5、e materials on which test work has shown it to be beneficial within given intensity ranges. It is not suitable for brittle materials. Hand peening and rotary flap peening are excluded specifically.1.2 Shot peening induce

6、s residual compressive stresses in the surface and near-surface layers of metallic articles, control- ling or limiting the reduction in fatigue properties that occurs from nickel or chromium plating of the article, or th

7、e fatigue properties of unplated articles.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of

8、 the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitati

9、ons prior to use.2. Referenced Documents2.1 ASTM Standards:2B183 Practice for Preparation of Low-Carbon Steel for ElectroplatingB242 Guide for Preparation of High-Carbon Steel for Elec- troplatingB320 Practice for Prepar

10、ation of Iron Castings for Electro- platingB322 Guide for Cleaning Metals Prior to Electroplating B607 Specification for Autocatalytic Nickel Boron Coatings for Engineering UseB650 Specification for Electrodeposited Engi

11、neering 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Guide for Autocatalytic (Electroless) Nickel- Phosphorus Deposition on Metals for Engineering Use (Discontinued 2000) (Withdrawn 2000)3B689 Specification for Electrop

12、lated Engineering Nickel CoatingsB733 Specification for Autocatalytic (Electroless) Nickel- Phosphorus Coatings on MetalE11 Specification for Woven Wire Test Sieve Cloth and Test SievesE165 Practice for Liquid Penetrant

13、Examination for General IndustryE709 Guide for Magnetic Particle Testing2.2 Federal Standards:4QQ-N-290 Nickel Plating (Electrodeposited) QQ-C-320 Chromium Plating (Electrodeposited)2.3 Military Standards:4MIL-S-851 Stee

14、l Grit, Shot, and Cut Wire Shot, and Iron Grit and Shot Blast Cleaning and PeeningMIL-S-13165 Shot Peening of Metal Parts MIL-C-26074 Coating, Electroless Nickel MIL-STD-45662 Calibration System Requirements2.4 SAE Stand

15、ards:5SAE J441 Cut Steel Wire Shot SAE J442 Test Strip, Holder and Gage for Shot Peening SEA J827 Cast Steel Shot SAE J1830 Size, Classification and Characteristics of Ce- ramic Shot for Peening1 This specification is un

16、der the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on Pre Treatment. Current edition approved Nov. 1, 2014. Published November 2014. Orig

17、inally approved in 1994. Discontinued January 2004 and reinstated in 2004 as B851–04. Last previous edition approved in 2009 as B851–09. DOI: 10.1520/B0851-04R14. 2 For referenced ASTM standards, visit the ASTM website,

18、www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.3 The last approved version of t

19、his historical standard is referenced on www.astm.org. 4 Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. 5 Available from Society of Aut

20、omotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1controlled for processing, monitori

21、ng, and documentation of the peening parameters critical to process certification.3.1.11 nozzle holding fixture—a fixture that holds the nozzles at the required location, distance, and angle in a locked position during t

22、he peening operation.3.1.12 process interrupt parameters—for critical peening operations, parameters such as shot flow, air pressure, part r/min, oscillation rate, and cycle time that must be monitored within process req

23、uirements.3.1.13 saturation—the minimum duration of peening nec- essary to achieve the desired Almen intensity which, when doubled, does not increase the Almen strip arc height by more than 10 %.3.1.14 saturation curve—a

24、 curve that plots peening time on the Almen strip (abscissa) versus Almen strip arc height (ordinate) achieved for the peening time (see Fig. 4).3.1.15 surface obliteration—the condition of a peened sur- face in which 10

25、0 % of the surface has been dimpled with shot impressions.NOTE 1—A100 % coverage is defined as that leaving unpeened 2 % or less of the original surface because the estimation of coverage of the impressions is difficult

26、when this is approximately 98 % of the total surface. The 100 % coverage is a theoretical limiting value. Hence, the term complete coverage is preferred. Complete coverage usually requires increasing the base time, that

27、is, the time of peening to reach 98 % coverage, by 15 to 20 %. Values of 200 %, 300 %, etc. are obtained by multiplying this run time by 2, 3, etc.4. Ordering Information4.1 When ordering articles to be shot peened, the

28、purchaser shall 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 shot size and uniformity required, if other than those

29、specified in 8.1.1.4.5 Peening intensity to be used at each location (see 8.2).4.6 Number, frequency, and locations of Almen test speci- mens to be provided for intensity verification and monitoring of the process if oth

30、er than those specified in 8.2, 8.2.1, and 8.2.2.4.7 Areas on the part that are to be shot peened and those to be protected from the peening (see 7.5).4.8 Whether magnetic particle or penetrant inspection is required bef

31、ore peening (see 7.2).4.9 Amount (percent) of coverage required in the areas to be peened. A complete coverage is the minimum requirement (see 3.1.6 and 8.3).4.10 Method for measuring coverage (see 8.3.1).4.11 Type of eq

32、uipment to be used, automated or computer- 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 reco

33、rds, as specified in Section 10.5. Significance and Use5.1 Shot peening is a process for cold working surfaces by bombarding the product with shot of a solid and spherical nature propelled at a relatively high velocity.

34、In general, shot peening will increase the fatigue life of a product that is subject to bending or torsional stress. It will improve resistance to stress corrosion cracking. It can be used to form parts or correct their

35、shapes. See Appendix X1 for additional information.5.2 It is essential that the shot peening process parameters be controlled rigidly to ensure repeatability from part to part and lot to lot.5.3 This specification covers

36、 techniques and methods nec- essary for proper control of the shot peening process.6. Materials and Equipment6.1 Shot Material Composition: 6.1.1 Cast Steel—Cast steel shot shall conform to the requirements of SAE J827.

37、6.1.2 Cut Wire—Cut wire shot shall be made from cold finished, round wire, confirming to SAE J441. 6.1.3 Ceramic Shot—Ceramic beads shall conform to the chemical composition given in Table 1 and to SAE J1830. 6.1.4 Shot

38、Form and Shape: 6.1.4.1 Cast Steel—Cast steel shot shall be spherical in shape and free of sharp edges, corners, and broken pieces. It shall conform to the acceptable shapes given in Fig. 5. The number of nonconforming s

39、hapes (see Fig. 6) shall not exceed the values given in Table 2. 6.1.4.2 Cut Wire—Cut wire shot shall be spherical in shape. It shall be free of sharp edges, corners, and broken pieces. The number of nonconforming shapes

40、 shall not exceed the values given in Table 2. 6.1.4.3 Ceramic Shot—Ceramic shot shall be spherical in shape and free of sharp edges, corners, and broken pieces. The number of nonconforming shapes shall not exceed the va

41、lues given in Table 2.FIG. 4 Saturation CurveTABLE 1 Composition of Ceramic ShotZrO2 , % SiO2 ,% Al2 O3 , % Fe2 O3 , % Free Iron, % Specific Gravity, g/cm 360.0–70.0 28.0–33.0 10.0 max 0.1 max 0.1 max 3.60–3.95B851 ? 04