SAE AMS 6477A pdf download

SAE AMS 6477A pdf download.Steel, Bars. Forgings, and Tubing 0.80Cr (0.90 – 1.03C) For Bearing Applications.
1,1 Form:
This specification covers a low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
1.2 Application:
These products have been used typically for bearing components requiring a through-hardening steel usually with hardness of approximately 60 HRC and section thickness under 0.50 inch (12.7 mm), but usage is not limited to such applications.
2. APPLICABLE DOCUMENTS:
The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been canceled and no superseding document has been specified, the last published issue of that document shall apply.
2.1 SAE Publications:
Available from SAE, 400 Commonwealth Drive. Warrendale, PA 15096-0001.
AMS 2251 Tolerances, Low-Alloy Steel Bars
MAM 2251 Tolerances, Metric. Low-Alloy Steel Bars
AMS 2253 Tolerances, Carbon and Alloy Steel Tubing
MAM 2253 Tolerances, Metric, Carbon and Alloy Steel Tubing
AMS 2259 Chemical Check Analysis Limits, Wrought Low-Alloy and Carbon Steels
3.2 Condition:
The product shall be supplied in the following condition; hardness and tensile strength shall be determined in accordance with ASTM A 370:
3.21 Bars:
3.21.1 Bars 0.500 Inch (12.70 mm) and Under In Nominal Diameter or Least Distance Between Parallel Sides: Cold finished, with mici-ostructure of spheroidized cementite in ferrite matrix, having tensile strength not higher than 120 ksi (825 MPa), or equivalent hardness (See 8.2).
3.2.1.2 Bars Over 0.500 Inch (12.70 mm) in Nominal Diameter or Least Distance Between Parallel Sides: Hot finished and annealed, unless otherwise ordered, with microstructure of spheroidized cementite in ferrite matrix, having hardness not higher than 207 HB. or equivalent (See 8.3). Bars ordered cold finished may have hardness as high as 248 HB, or equivalent.
3.2.2 Forgings: As ordered.
3.2.3 Mechanical Tubing: Cold finished and annealed. unless otherwise ordered, with microstructure of spheroidized cementite in ferrite matrix. Tubing ordered hot finished and annealed shall have hardness not higher than 95 HRB. or equivalent (See 8.3).
3.2.4 Forging Stock: As ordered by the forging manufacturer.
3.3 Properties:
The product shall conform to the following requirements: hardness testing shall be performed in accordance with ASTM A 370:
3.3.1 Macrostructure: Visual examination of transverse full cross-sections from bars, billets, tube rounds. or forging stock, etched in hot hydrochloric acid in accordance with ASTM E 381, shall show no pipe or cracks. Porosity. segregation, inclusions, and other imperfections shall be no worse than the macrographs of ASTM E 381 agreed upon by purchaser and vendor.
3.3.2 Micro-Inclusion Rating: At least one specimen from each ingot tested, as well as two-thirds of the total number of specimens and the average of all specimens, shall not exceed the limits shown in Table 2, determined in accordance with ASTM E 45, Method A.
3.3.3 Response to Heat Treatment: Specimens as in 4.3.3, protected by suitable means or treated in a neutral atmosphere to minimize scaling and prevent either carburization or decarburization, shall have substantially uniform hardness not lower than 63 HRC at any point below any permissible decarburization after being heated to 1525 °F ± 10 (830 C ± 5), held at heat for 20 minutes ± 2, and quenched in commercial paraffin oil (100 SLJS at 100 °F (38 SC)) at room temperature.
3.3.4 Decarbunzahon:
3.3.4.1 Bars and tubing ordered ground, turned, or polished shall be free from decarbunzation on the ground, turned, or polished surfaces. Decarburization on tubing ID shall not exceed the maximum depth specified in 3.3.4.4.
3.3.4.2 Allowable decarburization of bars, billets, and tube rounds ordered for redrawing or forging or to specified microstructural requirements other than spheroidized cementite in ferrite matrix shall be as agreed upon by purchaser and vendor.
3.3.4.3 Decarburization of bars for anti-friction balls and rollers to which 3.3.4.1 or 3.3.4.2 is not applicable shall be not greater than shown in Table 3.