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 2015 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:/www.sae.org/technical/standards/AMS6425D AEROSPACE MATERIAL SPECIFICATION AMS6425 REV. D Issued 1989-07 Revised 2
5、015-07 Superseding AMS6425C Steel, Bars, Forgings, and Tubing 1.4Mn - 1.5Si - 0.30Cr - 1.8Ni - 0.40Mo (0.23 - 0.28C) Consumable Electrode Vacuum Melted (Composition similar to UNS K32550) RATIONALE AMS6425D results from a Five Year Review and update of this specification and revises macrostructure,
6、decarburization and reporting. 1. SCOPE 1.1 Form This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. 1.2 Application These products have been used typically for parts requiring a through-hardening steel capable of
7、 developing a combination of high tensile strength, ductility, and fracture toughness, but usage is not limited to such applications. 1.2.1 Certain design and processing procedures may cause these products to become susceptible to stress-corrosion cracking after heat treatment. ARP1110 recommends pr
8、actices to minimize such conditions. 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 iss
9、ue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue 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
10、USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS2251 Tolerances, Low-Alloy Steel Bars AMS2253 Tolerances, Carbon and Alloy Steel Tubing SAE INTERNATIONAL AMS6425D Page 2 of 9 AMS2259 Chemical Check Analysis Limits, Wrought Low-Alloy and Carbon Steels AMS2300 Steel Cleanliness, Prem
11、ium Aircraft-Quality Magnetic Particle Inspection Procedure AMS2310 Qualification Sampling and Testing of Steels for Transverse Tensile Properties AMS2370 Quality Assurance Sampling and Testing, Carbon and Low-Alloy Steel Wrought Products and Forging Stock AMS2372 Quality Assurance Sampling and Test
12、ing Carbon and Low-Alloy Steel Forgings AMS2806 Identification Bars, Wire, Mechanical Tubing, and Extrusions, Carbon and Alloy Steels and Corrosion and Heat-Resistant Steels and Alloys AMS2808 Identification Forgings AS1182 Standard Stock Removal Allowance Aircraft-Quality and Premium Aircraft-Quali
13、ty Steel Bars and Mechanical Tubing ARP1110 Minimizing Stress Corrosion Cracking in Wrought Forms of Steels and Corrosion Resistant Steels and Alloys 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, ww
14、w.astm.org. ASTM A370 Mechanical Testing of Steel Products ASTM A604 Macroetch Testing of Consumable Electrode Remelted Steel Bars and Billets ASTM E112 Determining Average Grain Size ASTM E350 Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron
15、 ASTM E384 Knoop and Vickers Hardness of Materials ASTM E399 Plane-Strain Fracture Toughness of Metallic Materials 3. TECHNICAL REQUIREMENTS 3.1 Composition Shall conform to the percentages by weight shown in Table 1, determined by wet chemical methods in accordance with ASTM E350, by spectrochemica
16、l methods, or by other analytical methods acceptable to purchaser. Table 1 - Composition Element min max Carbon Manganese Silicon Phosphorus Sulfur Chromium Nickel Molybdenum Copper 0.23 1.20 1.30 - - 0.20 1.65 0.35 - 0.28 1.50 1.70 0.010 0.010 0.40 2.00 0.45 0.35 SAE INTERNATIONAL AMS6425D Page 3 o
17、f 9 3.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2259, except that check analysis limits for carbon shall apply to over maximum only. 3.2 Melting Practice Steel shall be multiple melted using consumable electrode vacuum practice in the remelt cycles. 3.3 C
18、ondition The product shall be supplied in the following condition; hardness and tensile strength shall be determined in accordance with ASTM A370: 3.3.1 Bars Bar shall not be cut from plate. 3.3.1.1 Bars 0.500 Inch (12.70 mm) and Under in Nominal Diameter or Least Distance Between Parallel Sides Col
19、d finished having tensile strength not higher than 145 ksi (1000 MPa) or equivalent hardness (See 8.2). 3.3.1.2 Bars Over 0.500 Inch (12.70 mm) in Nominal Diameter or Least Distance Between Parallel Sides Hot finished, unless otherwise ordered, annealed if necessary, having hardness not higher than
20、293 HB, or equivalent (See 8.3). Bars ordered cold finished may have hardness as high as 311 HB, or equivalent. 3.3.2 Forgings Normalized and tempered having hardness not higher than 311 HB, or equivalent (See 8.3). 3.3.3 Mechanical Tubing Cold finished, unless otherwise ordered, having hardness not
21、 higher than 32 HRC, or equivalent (See 8.3). Tubing ordered hot finished and annealed shall have hardness not higher than 31 HRC, or equivalent. 3.3.4 Forging Stock As ordered by the forging manufacturer. 3.4 Properties The product shall conform to the following requirements; hardness and tensile t
22、esting shall be performed in accordance with ASTM A370: 3.4.1 Macrostructure Visual examination of transverse full cross-sections from bars, billets, tube rounds, and forging stock, etched in hot hydrochloric acid in accordance with ASTM A604, shall show no pipe or cracks. Porosity, segregation, inc
23、lusions, and other imperfections shall be no worse than the macrographs of ASTM A604 shown in Table 2. Table 2 - Macrostructure limits Class Condition Severity 1 2 3 4 Freckles White Spots Radial Segregation Ring Pattern A A B B SAE INTERNATIONAL AMS6425D Page 4 of 9 3.4.2 Average Grain Size of Bar,
24、 Forgings, and Tubing Shall be ASTM No. 5 or finer, determined in accordance with ASTM E112. 3.4.3 Decarburization 3.4.3.1 Bars and tubing ordered ground, turned, or polished shall be free from decarburization on the ground, turned, or polished surfaces. Decarburization on tubing ID shall not exceed
25、 the maximum depth specified in Table 4. 3.4.3.2 Allowable decarburization of bars, billets, and tube rounds ordered for redrawing or forging or to specified microstructural requirements shall be as agreed upon by purchaser and producer. 3.4.3.3 Decarburization of bars that 3.4.3.1 or 3.4.3.2 is not
26、 applicable shall be not greater than shown in Table 3. Table 3A - Maximum total depth of decarburization, bars, inch/pound units Nominal Diameter or Distance Between Parallel Sides Inches Total Depth of Decarburization Inch Up to 0.375, incl Over 0.375 to 0.500, incl Over 0.500 to 0.625, incl Over
27、0.625 to 1.000, incl Over 1.000 to 1.500, incl Over 1.500 to 2.000, incl Over 2.000 to 2.500, incl Over 2.500 to 3.000, incl Over 3.000 to 5.000, incl 0.015 0.017 0.019 0.022 0.025 0.030 0.035 0.040 0.045 Table 3B - Maximum total depth of decarburization, bars, SI units Nominal Diameter or Distance
28、Between Parallel Sides Millimeters Total Depth of Decarburization Millimeters Up to 9.52, incl Over 9.52 to 12.70, incl Over 12.70 to 15.88, incl Over 15.88 to 25.40, incl Over 25.40 to 38.10, incl Over 38.10 to 50.80, incl Over 50.80 to 63.50, incl Over 63.50 to 76.20, incl Over 76.20 to 127.00, in
29、cl 0.38 0.43 0.48 0.56 0.64 0.76 0.89 1.02 1.14 3.4.3.4 Decarburization of tubing that 3.4.3.1 or 3.4.3.2 is not applicable shall be not greater than shown in Table 4. Table 4A - Maximum total depth of decarburization, tubing, inch/pound units Nominal Wall Thickness Inches Total Depth ID Inch Total
30、Depth OD Inch Up to 0.109, incl Over 0.109 to 0.203, incl Over 0.203 to 0.400, incl Over 0.400 to 0.600, incl Over 0.600 to 1.000, incl Over 1.000 0.008 0.010 0.012 0.015 0.017 0.020 0.015 0.020 0.025 0.030 0.035 0.040 Table 4B Maximum total depth of decarburization, tubing, SI units SAE INTERNATION
31、AL AMS6425D Page 5 of 9 Nominal Wall Thickness Millimeters Total Depth ID Millimeter Total Depth OD Millimeters Up to 2.77, incl Over 2.77 to 5.16, incl Over 5.16 to 10.16, incl Over 10.16 to 15.24, incl Over 15.24 to 25.40, incl Over 25.40 0.20 0.25 0.30 0.38 0.43 0.51 0.38 0.51 0.64 0.76 0.89 1.02
32、 3.4.3.5 Decarburization shall be evaluated by one of the two methods of 3.4.3.5.1 or 3.4.3.5.2. 3.4.3.5.1 Metallographic Method A cross section taken perpendicular to the surface shall be prepared, etched, and visually examined metallographically at a magnification not to exceed 100X. Optical indic
33、ations of decarburization (including complete decarburization ferrite plus partial decarburization) shall not exceed the limits of Tables 3 and 4. 3.4.3.5.2 Hardness Traverse Method The total depth of decarburization shall be determined by a traverse method using microhardness testing in accordance
34、with ASTM E384, at a magnification not exceeding 100X, conducted on a hardened but untempered specimen protected during heat treatment to prevent changes in surface carbon content. Depth of decarburization is defined as the perpendicular distance from the surface to the depth under that surface wher
35、e there is not further increase in hardness. Such measurements shall be far enough away from any adjacent surface to be uninfluenced by any decarburization on the adjacent surface. Acceptance shall be as listed in Tables 3 and 4. 3.4.3.5.2.1 When determining the depth of decarburization, it is permi
36、ssible to disregard local areas provided the decarburization of such areas does not exceed the above limits by more than 0.005 inch (0.13 mm) and the width is 0.065 inches (1.65 mm) or less. 3.4.3.6 In case of dispute, the total depth of decarburization determined using the microhardness traverse me
37、thod shall govern. 3.4.4 Response to Heat Treatment of Bar, Forgings, and Tubing Specimens shall have the following properties after being normalized by heating to 1725 F 25 (941 C 14), holding at heat for 1 hour per inch (25 mm) of maximum cross-section, and cooling at a rate equivalent to air cool
38、ing, hardened by heating to 1600 F 25 (871 C 14), holding at heat for 1 hour per inch (25 mm) of maximum cross-section, and quenching in oil, and tempered by heating to 550 F 10 (288 C 6), holding at heat for 2 to 3 hours, and cooling in air to room temperature: 3.4.4.1 Longitudinal Tensile Properti
39、es Shall be as specified in Table 5; testing in the longitudinal direction need not be performed on product tested in the transverse direction. Table 5 - Minimum longitudinal tensile properties Property Value Tensile Strength Yield Strength at 0.2% Offset Elongation in 4D Reduction of Area 220 ksi (
40、1517 MPa) 185 ksi (1276 MPa) 10% 30% SAE INTERNATIONAL AMS6425D Page 6 of 9 3.4.4.2 Transverse Tensile Properties Shall be as shown in Table 6, determined on specimens selected and prepared in accordance with AMS2310; transverse properties apply only to product from which tensile specimens not less
41、than 2.50 inches (63.5 mm) in length can be taken. Table 6A - Minimum transverse tensile properties, inch/pound units Nominal Cross-Sectional Area Square Inches Tensile Strength ksi Yield Strength at 0.2% Offset ksi Reduction of Area % Average Reduction of Area % Individual Up to 100, incl Over 100
42、to 144, incl Over 144 to 225, incl 220 220 220 185 185 185 30 25 20 25 20 15 Table 6B - Minimum transverse tensile properties, SI UNITS Nominal Cross-Sectional Area Square Centimeters Tensile Strength MPa Yield Strength at 0.2% Offset MPa Reduction of Area % Average Reduction of Area % Individual Up
43、 to 645, incl Over 645 to 929, incl Over 929 to 1452, incl 1517 1517 1517 1276 1276 1276 30 25 20 25 20 15 3.4.4.3 Fracture Toughness When specified, bars and/or forgings shall be subjected to fracture toughness testing as follows: 3.4.4.3.1 Bars Shall be not lower than 100 ksi (110 MPa ), KICor KQ,
44、 determined in accordance with ASTM E399 on specimens in the LS (preferred) or LT orientation from bars 1.50 inches (38.1 mm) and over in section thickness and 4.0 inches (102 mm) and over wide. 3.4.4.3.2 Forgings Shall be not lower than 100 ksi (110 MPa ), KICor KQ, determined in accordance with AS
45、TM E399 on specimens in the TL orientation from forgings 1.50 inches (38.1 mm) and over in section thickness. 3.5 Quality The product, as received by purchaser, shall be uniform in quality and condition, sound, and free from foreign materials and from imperfections detrimental to usage of the produc
46、t. 3.5.1 Steel shall be premium aircraft-quality conforming to AMS2300 except that a maximum average frequency (F) rating of 0.10 and a maximum average severity (S) rating of 0.20 shall apply. 3.5.2 Bars and tubing ordered hot rolled or cold drawn, or ground, turned, or polished shall, after removal
47、 of the standard stock removal allowance in accordance with AS1182, be free from seams, laps, tears, and cracks open to the machined, ground, turned, or polished surface. 3.5.3 Grain flow of die forgings, except in areas that contain flash-line end grain, shall follow the general contour of the forg
48、ings showing no evidence of reentrant grain flow. SAE INTERNATIONAL AMS6425D Page 7 of 9 3.6 Tolerances 3.6.1 Bars In accordance with AMS2251. 3.6.2 Mechanical Tubing In accordance with AMS2253. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The producer of the product shall suppl
49、y all samples for producers tests and shall be responsible for the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Composition (3.1), condition (3.3), macrostructure (3.4.1), average grain size (3.4.2), decarb
