1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2006 03 17 Revised Inserted 3.0; Deleted 3.12 Revised 5. 1978 10 04 Metricated & Retyped CWI0H-RD-824168 1974 01 11 Released CW10B-PR-702789 Printed copies are uncontrolled Copyright 2006, Ford Global Technologies, LLC Page 1 of 3 STEEL BALLS,
2、 CHROME ALLOY, VACUUM PROCESSED ESW-M1A130-B 1. SCOPE The materials defined by this specification are purchased finished, vacuum processed, chrome alloy steel balls. 2. APPLICATION This specification was released originally for material used in automotive ball bearings. 3. REQUIREMENTS 3.0 STANDARD
3、REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.1 MELTING PRACTICE The vacuum processed material shall be of uniform composition and uniform grain structure, free from physical
4、 defects, clean, and of the highest quality in every respect as described and defined in the sections which follow. 3.2 CHEMICAL COMPOSITION 52100 Carbon 0.95 - 1.10 Manganese 0.25 - 0.45 Phosphorus 0.025 max Sulfur 0.025 max Silicon 0.20 - 0.35 Chromium 1.30 - 1.60 Nickel 0.35 max Copper 0.25 max M
5、olybdenum 0.08 max Analysis made by purchaser on samples taken at random from each lot or sample thereof shall fall within the specified limits. The standard permissible variation in analysis from the values specified shall be as follows: PERMISSIBLE VARIATION +/- % Carbon 0.03 Manganese 0.03 Phosph
6、orus 0.005 Sulfur 0.005 Silicon 0.02 Chromium 0.05 ENGINEERING MATERIAL SPECIFICATIONESW-M1A130-B Printed copies are uncontrolled Copyright 2006, Ford Global Technologies, LLC Page 2 of 3 3.3 SEAM DEPTH Each coil of wire for balls must be inspected for seams. The maximum allowable seam or surface de
7、fect is as follows: Size -O.D Max. Depth of Seam Cold Finished Wire & Rod Up to 0.250 in (6.4 mm) 0.003 in (0.08 mm) 0.251-0.500 in (6.4-12.70 mm) 0.004 in (0.10 mm) 0.501-0.750 in (12.70-19.05 mm) 0.006 in (0.15 mm) 0.751 in-over (19.08 mm-over) 0.008 in (0.20 mm) Hot Rolled Annealed 0.222-0.500 in
8、 (5.64-12.70 mm) 0.005 in (0.13 mm) 0.501-0.700 in (12.70-17.78 mm) 0.007 in (0.18 mm) Annealed & Skin Passed Up to 0.250 in (6.4 mm) 0.005 in (0.13 mm) 0.251-0.500 in (6.4-12.70 mm) 0.006 in (0.15 mm) 0.501-0.750 in (12.70-19.05 mm) 0.008 in (0.20 mm) 3.4 HARDNESS The ball shall be uniformly throug
9、h hardened to an as-quenched hardness of Rockwell C 64 minimum followed by a temper at 150 C minimum to obtain a Rockwell “C“ (or equivalent) hardness of 61 to 64 as measured on parallel flats. Balls in any lot and unit container shall have a uniform hardness within two points Rockwell “C“ as measur
10、ed on parallel flats. For convenience sake, hardness may be measured on the curved ball surface, taking into account the necessary correction factor. In case of controversy, however, readings shall be made on parallel flats, ground carefully to avoid grinding damage on the balls. Note: Case hardened
11、 balls will not be acceptable at any time. 3.5 FRACTURE GRAIN SIZE The fracture grain size shall be No. 8 or finer as determined on fractured balls. Compare with Shepherd fracture grain size standards. 3.6 SURFACE DEFECTS Balls etched in a 50% HCl solution for 30 minutes at 80 C, brushed off with so
12、ft brush, and examined under a well diffused light shall be free from surface defects (seams, laps, scratches, decarburization, rush and pipe). No cracks, pits, or excessive porosity shall be present. 3.7 SURFACE TEMPER INSPECTION Balls shall be etched per manufacturing process standard MS 6-2. 3.8
13、NON-METALLIC INCLUSION AND SEGREGATION Cleanliness of the steel will be judged by the size and distribution of non-metallic inclusions observed in the hardened fracture and confirmed by metallographic examination at 100X magnification of polished specimens. The examination of a polished specimen sha
14、ll be on a plane through “poles“ of the balls as determined by hot etching. ENGINEERING MATERIAL SPECIFICATIONESW-M1A130-B Printed copies are uncontrolled Copyright 2006, Ford Global Technologies, LLC Page 3 of 3 The micro-cleanliness rating shall be performed on a plane through the ball “poles“ as
15、determined by hot etch. The rating of the specimen shall be in accordance with the modified JK chart (ASTM E 45 Method “D“). The worst field of each inclusion type from each specimen shall be recorded as a specimen rating. Two thirds of all the polished samples and the average of all samples shall n
16、ot exceed the following ratings: Inclusion Type Thin Thick A 2 1-1/2 B 2 1-1/2 C 2 1-1/2 D 1-1/2 1-1/2 3.9 FRACTURE ANALYSIS A defective fracture shall be defined as follows: . The presence of more than one slag streak 1/16 - 1/8 in (1.5 - 3.0 mm) in length. . The presence of one slag streak over 1/
17、8 in (3 mm) in length. . The presence of porosity hairline cracks, forging burst, and ingot pipe. If 10% of more of the total samples are defective, the whole lot shall be rejected. Streakiness, representing excessive segregation, appearing as pronounced light and dark bands in the hardened fracture
18、 and readily distinguished at 100X magnification on a polished etched mounted specimen examined in a plane through the ball “poles“ is not acceptable. 3.10 MICROSTRUCTURE The microstructure shall be examined on a polished specimen etched in a suitable nital etch. The microstructure shall be that of
19、fine, uniformly tempered martensite, free from excessive carbide segregation. There shall be no decarburization present. There shall be no evidence of overheating during hardening. 3.11 MAGNETIC COMPARATOR CHECK Ball shall be checked 100% for hardness and composition by magnetic comparator or equiva
20、lent non-destructive test method. 5. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of this specification. 5.1 SIMILAR SPECIFICATIONS The following similar specifications are listed for information only and shall not be construed as acceptable alternates unless all requirements of this material specification are met. ASTM A 295 - Latest Revision Section No. 10 - AFBMA Standard for Balls ASTM E 45 - Latest Revision MIL-B-1083A - Latest Revision FF-B-171 - Latest Revision
