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 there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this p
3、ublication may 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: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/AMS2431/2F AEROSPACE MATERIAL SPECIFICATION AMS2431 /2 REV. F Issued 1988-04 Revised 2017-11 Su
5、perseding AMS2431/2E Peening Media (ASH) Cast Steel Shot, High Hardness (55 to 62 HRC) RATIONALE AMS2431/2F is the result of a Five-Year Technical Review with changes to 3.2 (composition) and 3.9.1 (size screening test). 1. SCOPE 1.1 Purpose This specification, in conjunction with the general requir
6、ements for peening media covered in AMS2431, establishes the requirements for the procurement of cast steel shot with a hardness of 55 to 62 HRC. 1.2 Application Cast steel shot, high hardness, have been used typically in peening metal surfaces to impart compressive stresses to these surfaces thereb
7、y increasing resistance to fatigue and stress-corrosion cracking, but usage is not limited to such applications. Generally, high hardness cast steel shot is used on parts of hardness 50 HRC or over. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase or
8、der 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 cancelled and no superseding document has been specified, the last published issue
9、of that document shall apply. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS2431 Peening Media, General Requirements SAE INTERNATIONAL AMS2431 /2F P
10、age 2 of 7 3. TECHNICAL REQUIREMENTS 3.1 Cast steel shot, high hardness, shall conform to AMS2431 and the requirements specified herein. 3.2 Composition shall conform to the percentages by weight shown in Table 1, determined as specified in AMS2431 and as follows. Table 1 - Composition Element Min M
11、ax Carbon 0.80 1.20 Manganese (3.2.1) - 1.20 Silicon 0.40 1.50 Phosphorus - 0.05 Sulfur - 0.05 3.2.1 Minimum manganese content shall conform to the minimum percentage by weight shown in Table 2. Table 2 - Minimum manganese content Shot Size Wt Percent ASH-70 to ASH-130 0.35 ASH-170 and ASH-190 0.50
12、ASH-230 and up 0.60 3.3 Hardness Not less than 90% of the readings, using a microhardness tester with a minimum 500 g load, shall fall within the range of 55 to 62 HRC, or equivalent, determined in accordance with ASTM E384 (see 8.4). 3.4 Microstructure shall exhibit uniformly tempered martensite wi
13、th fine, well-distributed carbides determined in accordance with 3.9.4. 3.5 Density shall be not less than 7.0 g per mL, 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 3.7.1 Shape, determined in accordance with 3.9.3. 3.
14、7.1.1 Acceptable Shapes Shapes conforming to Figure 1 are acceptable. 3.7.1.2 Marginal Shapes Shapes conforming to Figure 2 are permissible to the extent specified in Table 3. 3.7.1.3 Unacceptable Shapes Shapes conforming to Figure 3 are permissible to the extent specified in Table 3. SAE INTERNATIO
15、NAL AMS2431 /2F Page 3 of 7 Table 3 - Shape requirements Shot Size Area per Field Square Inch (mm2) Number of Fields Viewed Number of Marginal Particles (1), max Number of Unacceptable Particles, (2), max ASH 930 1 (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
16、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 (40) 1 14 5 ASH 70 0.0625 (40) 1 39 13 Notes: (1) Maximum number of marginal shapes i
17、s 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 number of particles viewed. 3.7.2 Internal Defects No more than 15% of the particles,
18、 by count, may exhibit cracks, hollows, or shrinkage determined in accordance with 4.1.7 (see Figure 4). 3.8 Shot Size Size shall conform to the requirements of Table 4, determined in accordance with 3.9.1. Table 4 - Screening requirements (1) Shot Size 0% Max 2% Max on Screen 50% Max Cumulative on
19、Screen 90% Min Cumulative on Screen 98% Min Cumulative 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
20、(0.0555) 16 (0.0469) ASH 460 10 (0.0787) 12 (0.0661) 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
21、 18 (0.0394) 20 (0.0331) 25 (0.0278) 30 (0.0234) 35 (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
22、(0.0139) 50 (0.0117) 80 (0.0070) ASH 70 40 (0.0165) 45 (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). SAE INTERNATIONAL AMS2431 /2F Page 4 of 7 3.9 Test Methods and Procedures 3.9.1 Size Screening Te
23、st The size of shot, specified in 3.8, shall be determined by using a 100 g (approximately) sample and screening as follows: The required standard testing sieves in accordance with ASTM E11 or ISO 3310-1 shall be nested in ascending order with a pan on the bottom. The test sieves diameter shall be a
24、 minimum 8 inches (203.2 mm) and height of 1 inch (25.4 mm) or 2 inches (50.8 mm). The 100 g sample shall be poured onto the top sieve and the nested sieves shall be placed in a rotating and tapping type of shaking machine. The rotating speed shall be 270 to 300 rpm and the tapping speed shall be 14
25、0 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 screen shall be determined by weighing the shot retained on each screen. 3.9.2
26、 Density Approximately 60 g of shot, previously dried and weighed to the nearest 0.1 g, shall be placed in a 100 mL graduated cylinder containing 50 mL of ethanol or methanol. The total volume minus 50 mL represents the volume of the shot. The density is determined using Equation 1. Density = Shot w
27、eight (g) 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. 3.9.4 Microstructure The sample shall be mounted, polished, and etched with 2% Nital, or other
28、 suitable etchant, and examined using a microscope at approximately 500X magnification. 4. QUALITY ASSURANCE PROVISIONS Shall be in accordance with AMS2431 and the following. 4.1 Sampling and Testing Two samples of approximately 800 g each shall be selected from separate containers chosen at random
29、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 microhardness readings shall be made from each sample with no more than one impression on any
30、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 single layer of shot in a plastic mount and polishing down to nominal half spheres. 4.1.3 Micros
31、tructure The sample used for hardness testing may also be used for microstructure evaluation. SAE INTERNATIONAL AMS2431 /2F Page 5 of 7 4.1.4 Density Two 60 g samples shall be evaluated for density determination. 4.1.5 Size Two representative samples of not less than 100 g each shall be used for siz
32、e 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 shot, in one layer, which completely fills the areas spec
33、ified in Table 3. The number of areas, or fields of view, evaluated at 10 to 30X magnification for each shot size shall be as indicated in Table 3 (see 3.9.3). 4.1.6.1 Alternative methods of inspection for shape are permitted provided that they can be correlated to the optical method and are accepta
34、ble 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 shrinkage. A maximum of 10%, by count, of particles evalua
35、ted 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 defects, cracks, hollows, or shrinkage (see 3.7.4). Parti
36、cles 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. 5. PREPARATION FOR DELIVERY Shall be in accordance with AMS2431 and the following: 5.1 Packaging and Identification Steel shot shall be packaged in 40 to 55-p
37、ound (18 to 25 kg) units in plastic coated bags or pails or as approved by the purchaser. 6. ACKNOWLEDGMENT Shall be in accordance with AMS2431. 7. REJECTIONS Shall be in accordance with AMS2431. 8. NOTES 8.1 See AMS2431 and the following. 8.2 Revision Indicator A change bar (I) located in the left
38、margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change ba
39、rs and (R) are not used in original publications, nor in documents that contain editorial changes only. SAE INTERNATIONAL AMS2431 /2F Page 6 of 7 8.3 Terms used in AMS are clarified in ARP1917 and as follows. 8.3.1 Cracked shot is one that exhibits a linear discontinuity with length greater than thr
40、ee times its width and length greater than 20% of the particle diameter. 8.3.2 Hollow is a void with an area that is greater than 10% of the area of the shot particle. 8.3.3 Shrinkage is an internal cavity with an irregular dendritic surface and is greater than 40% of the area of the shot particle a
41、rea. 8.3.4 Elongated particle is one that the length is approximately twice the diameter of the particle. 8.4 Hardness conversions to Rockwell C values for metals are presented in ASTM E140. 8.5 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary; dimensions and
42、 properties in SI units and the Celsius temperatures are shown as the approximate equivalents of the primary units and are presented only for information. Figure 1 - Acceptable shapes Figure 2 - Marginal shapes Figure 3 - Unacceptable shapes SAE INTERNATIONAL AMS2431 /2F Page 7 of 7 Figure 4 - Internal defects PREPARED BY ASEC AND AMS COMMITTEE “B”
