ASTM-B851:04(R2020) pdf free download – Standard Specification for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel, Autocatalytic Nickel, or Chromium Plating, or as Final Finish.
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 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 values given in Table 2.
6.1.5 Hardness—The hardness of the media shall exceed that of the material to be processed.
6.1 .5.1 cast Steel—Cast steel shot shall have a hardness of HR. 45 to HR. 55. Special hard cast steel shot shall be used on products harder than HR( 50 and shall have a hardness of HR. 55 to HR. 65.
6.1.5.2 Cut Wire—Cut wire shot shall have a hardness equal to or greater than that given in Table 3.
6. 1 .5.3 ceramic Shot—Ceramic shot shall have a minimum hardness of 560 [1V3() (30 kgf.
6.1.6 Size:
(1) The size of the media shall be capable of producing the required intensity in the required time.
(2) If a peened surface contains a fillet, the nominal size of the 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 shall not exceed one-fourth of the width or the diameter of the opening.
6.1.6.1 cast Steel—Cast steel shot charged into a machine shall conform to the screen requirements given in Table 4 for the nominal size selected. When a machine has a completely new charge of cast steel shot, conditioning shall he conducted, to remove the oxide layers on the shots, by bombarding onto a hardened steel surface for a minimum of two passes. Conditioning may not be required if the addition to the charge already in the machine is below 25 %. If the addition of over 25 % is made to the charge. conditioning is required.
6.1.6.2 Cut Wire—The diameter of cut wire shot charged into a machine shall conform to the requirements given in Table 4. Cut wire shot shall conform to the requirements of length and cumulative weight given in Table 5. It is mandatory that only preconditioned cut wire shot be used.
7.2 Flaw and Crack Tesiing—When required. magnetic particle, penetrant, ultrasonic, or other flaw or crack detection processes shall be completed prior to peening. See Test Method El65 and Guide E709.
7.3 corrosion and Damage—Parts shall not he peened if they show evidence of invasive corrosion or mechanical damage on the surface.
7.4 Cleaning—Cleaning prior to peening shall be accomplished by vapor degreasing, solvent wiping, warm solvent spray, or an acceptable water-base nonflammable product, as required. to remove all soils, scale, and coatings from the surface areas to be pecncd. See Practices 13183, B242, B320, and B322.
7.5 Masking—Surfaces designated on the drawing to be free of shot peening marks shall be masked or otherwise protected from the shot stream or indirect impingement by shot.
7.5.1 Suitable masking materials are adhesive tape, sheet rubber, etc.