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1、 SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2007 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org AMS 2431/2D AEROSPACE MATERIAL SPECIFICATION Issued APR 1988 Revised MAY 2007 Superseding AMS 2431/2C Peening Media (ASH) Cast Steel Shot, High Hardness (55 to 62 HRC) RATIONALE AMS 2431/2D is a Five Year Review and u
5、pdate of this specification. 1. SCOPE The complete requirements for procuring the product shall consist of this document and the latest issue of the basic specification, AMS 2431. 1.1 Application Cast steel shot, high hardness, conforming to this specification is intended for use in peening metal su
6、rfaces to impart compressive stresses to these surfaces thereby increasing resistance to fatigue and stress-corrosion cracking. Generally, high hardness cast steel shot is used on parts of hardness 50 HRC or over 2. APPLICABLE DOCUMENTS See AMS 2431. 3. TECHNICAL REQUIREMENTS 3.1 Cast steel shot, hi
7、gh hardness, shall conform to AMS 2431 and the requirements specified herein. 3.2 Composition shall conform to the percentages by weight shown in Table 1, determined in accordance with ASTM E 350. TABLE 1 - COMPOSITION Element min max Carbon 0.80 1.20 Manganese (3.2.1) - 1.20 Silicon 0.40 1.50 Phosp
8、horus - 0.05 Sulfur - 0.05 3.2.1 Minimum manganese content shall conform to the minimum percentage by weight shown in Table 2. SAE AMS 2431/2D - 2 - TABLE 2 - MINIMUM MANGANESE CONTENT Shot Size Wt Percent ASH-70 to ASH-130 0.35 ASH-170 and ASH-190 0.50 ASH-230 and up 0.60 3.3 Hardness Not less than
9、 90% of the readings, using a microhardness tester with a minimum 500 gram load, shall fall within the range of 55 to 62 HRC, or equivalent (See 8.2), determined in accordance with ASTM E 384. 3.4 Microstructure shall exhibit uniformly tempered martensite with fine, well-distributed carbides. 3.5 De
10、nsity shall be not less than 7.0 grams per milliliter, determined in accordance with 3.9.2. 3.6 Contamination Shot shall be clean and free of dirt, grit, oil, or grease. 3.7 Quality requirements shall conform to 3.7.1, 3.7.2, 3.7.3, and 3.7.4, determined in accordance with 3.9.3. 3.7.1 Acceptable Sh
11、apes Shapes in accordance with Figure 1 are acceptable. 3.7.2 Marginal Shapes Shapes conforming to Figure 2 are permissible to the extent specified in Table 3. 3.7.3 Unacceptable Shapes Shapes conforming to Figure 3 are permissible to the extent specified in Table 3. 3.7.4 Internal Defects No more t
12、han 15% of the particles, by count, may exhibit cracks, hollows, or shrinkage (See Figure 4). TABLE 3 - SHAPE REQUIREMENTS Shot Size Area per Field Square Inch (mm2) Number of Fields Viewed Number of Marginal Particles All Fields(1), max Number of Unacceptable Particles, All Fields(2), max ASH 930 1
13、 (645) 1 8 2 ASH 780 1 (645) 1 12 2 ASH 660 1 (645) 1 16 3 ASH 550 1 (645) 1 20 4 ASH 460 1 (645) 1 28 5 ASH 390 1 (645) 1 39 7 ASH 330 0.25 (161) 1 14 3 ASH 280 0.25 (161) 1 20 4 ASH 230 0.25 (161) 1 14 5 ASH 190 0.25 (161) 1 20 7 ASH 170 0.25 (161) 1 28 10 ASH 130 0.0625 (40) 1 10 4 ASH 110 0.0625
14、 (40) 1 14 5 ASH 70 0.0625 (40) 1 39 13 Notes: (1) Maximum number of marginal shapes is approximately 3% of the total number of particles viewed for ASH 70 to ASH 230, 6% for ASH 280 to ASH 550, and 7% for ASH 660 to ASH 930. (2) Maximum number of unacceptable shapes is approximately 1% of the total
15、 number of particles viewed. -,-,- SAE AMS 2431/2D - 3 - 3.8 Size shall conform to the requirements of Table 4, determined in accordance with 3.9.1. TABLE 4 - SCREENING REQUIREMENTS Shot Size All Pass Screen 2% max on Screen 50% max Cumulative on Screen 90% min Cumulative on Screen 98% min Cumulativ
16、e on Screen ASH 930 5 (0.157) 6 (0.132) 7 (0.111) 8 (0.0937) 10 (0.0787) ASH 780 6 (0.132) 7 (0.111) 8 (0.0937) 10 (0.0787) 12 (0.0661) ASH 660 7 (0.111) 8 (0.0937) 10 (0.0787) 12 (0.0661) 14 (0.0555) ASH 550 8 (0.0937) 10 (0.0787) 12 (0.0661) 14 (0.0555) 16 (0.0469) ASH 460 10 (0.0787) 12 (0.0661)
17、14 (0.0555) 16 (0.0469) 18 (0.0394) ASH 390 12 (0.0661) 14 (0.0555) 16 (0.0469) 18 (0.0394) 20 (0.0331) ASH 330 14 (0.0555) 16 (0.0469) 18 (0.0394) 20 (0.0331) 25 (0.0278) ASH 280 16 (0.0469) 18 (0.0394) 20 (0.0331) 25 (0.0278) 30 (0.0234) ASH 230 18 (0.0394) 20 (0.0331) 25 (0.0278) 30 (0.0234) 35 (
18、0.0197) ASH 190 20 (0.0331) 25 (0.0278) 30 (0.0234) 35 (0.0197) 40 (0.0165) ASH 170 25 (0.0278) 30 (0.0234) 35 (0.0197) 40 (0.0165) 45 (0.0139) ASH 130 30 (0.0234) 35 (0.0197) 40 (0.0165) 45 (0.0139) 50 (0.0117) ASH 110 35 (0.0197) 40 (0.0165) 45 (0.0139) 50 (0.0117) 80 (0.0070) ASH 70 40 (0.0165) 4
19、5 (0.0139) 50 (0.0117) 80 (0.0070) 120 (0.0049) Notes: (1) Nominal Size = 90% Screen Opening (e.g.: Nominal size of ASH 230 shot is 0.0234 diameter. 3.9 Test Methods and Procedures 3.9.1 Size Screening Test The size of shot, specified in 3.8, shall be determined by using a 100-gram (approximately) s
20、ample and screening as follows: The required standard testing sieves in accordance with ASTM E 11 shall be nested in ascending order with a pan on the bottom. The 100-gram sample shall be poured onto the top sieve and the nested sieves shall be placed in a rotating and tapping type of shaking machin
21、e. The rotating speed shall be 275 to 295 rpm and the tapping speed shall be 145 to 160 taps per minute. Shaking and tapping shall be continued for 5 minutes 5 seconds for sieves 30 mesh and coarser and 10 minutes 5 seconds for sieves finer than 30 mesh. After shaking, the percentage of shot on each
22、 screen shall be determined by weighing the shot retained on each screen. 3.9.2 Density Approximately 60 grams of shot, previously dried and weighed to the nearest 0.1 gram, shall be placed in a 100 mL graduated cylinder containing 50 mL of ethanol or methanol. The total volume minus 50 mL represent
23、s the volume of the shot. The density is determined using Equation 1. Density = Shot weight (grams) Shot volume (ml) (Eq. 1) 3.9.3 Shape Visual evaluation, at a magnification of 10 to 30X shall be performed using the areas and number of fields specified in Table 3 for each respective shot size. 3.9.
24、4 Microstructure The sample shall be mounted, polished, and etched with 2% Nital, or other suitable etchant, and examined using a microscope at approximately 500X magnification. SAE AMS 2431/2D - 4 - 4. QUALITY ASSURANCE PROVISIONS See AMS 2431 and the following: 4.1 Sampling and Testing Two samples
25、 of approximately 800 grams each shall be selected from separate containers chosen at random from each lot. Each sample shall be split using a sample splitter to test quantities as follows: 4.1.1 Composition Not less than two samples from each lot shall be evaluated. 4.1.2 Hardness A minimum of 20 m
26、icrohardness readings shall be made from each sample with no more than one impression on any one shot. The hardness test impression shall be located approximately midway between the surface and the center of the shot. 4.1.2.1 Samples for microhardness testing shall be prepared by encapsulating a sin
27、gle layer of shot in a plastic mount and polishing down to nominal half spheres. 4.1.3 Microstructure The sample used for hardness testing may also be used for microstructure evaluation. 4.1.4 Density Two 60-gram samples shall be evaluated for density determination. 4.1.5 Size Two representative sam
28、ples of not less than 100 grams each shall be used for size evaluation. 4.1.5.1 Alternative methods for size evaluation may be utilized provided that they can be correlated to the sieve analysis method and are acceptable to purchaser. 4.1.6 Shape A representative sample shall consist of an amount of
29、 shot, in one layer, which completely fills the areas specified in Table 3. The number of areas, or fields of view, evaluated at 10 to 30X magnification (See 3.9.3) for each shot size shall be as indicated in Table 3. 4.1.6.1 Alternative methods of inspection for shape are permitted provided that th
30、ey can be correlated to the optical method and are acceptable to purchaser. 4.1.7 Internal Defects The mount prepared for microhardness testing shall be also used to evaluate defects. A minimum of 100 particles shall be evaluated for defects. Internal defects (Figure 4) include cracks, hollows, and
31、shrinkage. A maximum of 10%, by count, of particles evaluated may contain cracks. A maximum of 10%, by count, of particles evaluated may contain hollows. A maximum of 10%, by count, of particles evaluated may contain shrinkage. A maximum total of 15%, by count, of particles evaluated may exhibit any
32、 defects, cracks, hollows, or shrinkage (See 3.7.4). Particles with more than one defect shall be counted only once in the total. A magnification of 10 to 30X shall be used for evaluation of defects. -,-,- SAE AMS 2431/2D - 5 - 5. PREPARATION FOR DELIVERY See AMS 2431 and the following: 5.1 Packagin
33、g and Identification Steel shot shall be packaged in 40 to 55 pound (18 to 25 kg) units in plastic coated bags or pails. 6. ACKNOWLEDGMENT See AMS 2431. 7. REJECTIONS See AMS 2431. 8. NOTES See AMS 2431 and the following: 8.1 Terms used in AMS are clarified in ARP1917 and as follows: 8.1.1 Cracked s
34、hot is one that exhibits a linear discontinuity with length greater than three times its width and length greater than 20% of the particle diameter. 8.1.2 Hollow is a void with an area that is greater than 10% of the area of the shot particle. 8.1.3 Shrinkage is an internal cavity with an irregular
35、dendritic surface and is greater than 40% of the area of the shot particle area. 8.2 Hardness conversions to Rockwell C values for metals are presented in ASTM E 140. 8.3 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary; dimensions and properties in SI units
36、and the Celsius temperatures are shown as the approximate equivalents of the primary units and are presented only for information. PREPARED BY AMS COMMITTEE “B” SAE AMS 2431/2D - 6 - FIGURE 1 - ACCEPTABLE SHAPES FIGURE 2 - MARGINAL SHAPES FIGURE 3 - UNACCEPTABLE SHAPES FIGURE 4 - INTERNAL DEFECTS -,-,-