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Chemical compositions of AISI (ASTM/ASME) and UNS martensitic and precipitation hardening stainless steel grades

Introduction – AISI ASTM ASME and UNS

Most ASTM and ASME standards list the steel grades by their UNS (Unified Numbering system) numbers but also make reference, where appropriate to the more general AISI (American Iron and Steel Institute) grade designations. These grade numbering systems are widely used in the USA, where they originated and are recognised by most stainless steel specifiers and users.
The American Iron and Steel Institute (AISI) developed designations such as 420, 440 etc and published compositions for these in their ‘Steel Products Manual’ (1974).
These are NOT specifications, but steel grade composition ranges only.
These grades were used by the American Society Testing and Materials (ASTM) to identify grades in a wide range of standards they published for stainless products, such as sheets and plates (ASTM A240), bars (ASTM A276) and tubes (ASTM A269).
The compositions of the AISI grades were made more specific with the introduction of the ‘Unified Numbering System’, jointly established by ASTM and SAE (Society of Automotive Engineers).
This five digit number, preceded by the letter ‘S’ for most stainless steels, identified the specific variant of the grade

e.g. 420 being UNS S42000, 630 or 17/4PH being UNS S17400

American Society of Mechanical Engineers (ASME) publish design codes and standards for pressure applications. ASME standards are generally based on the appropriate ASTM standards, but the standard numbers are preceded with the letters ‘SA’, rather than just the ‘A’ of the ASTM standards.
Where UNS grade numbers are used, these are universal, regardless of the product type or the standard in which they appear.

The AISI designations have been adopted in Japan. The AISI number is preceded with the letters SUS e.g. SUS 630. The Japanese have developed variants on some grades for certain product forms e.g. SUS 304J1 for sheet products.
The composition ranges should always be checked in the appropriate standard.

Composition tables

The tables in this article use the UNS number as their key, but also show the related AISI and SAE numbers. Where appropriate, common names for the steels are also shown.
As an alternative to scanning down the list try the ‘find’ facility on your keyboard, using the ‘Ctrl’ and ‘F’ keys together. Type in the term you are looking for in the dialog box that then appears.
The data given is not intended to replace that shown in individual standards to which reference should always be made.

Martensitic and precipitation hardening grades

 

Designation Chemical composition % by mass max unless stated
UNS No SAE No AISI No / Common Name C Si Mn P S Cr Mo Ni Others
S13800 XM-13 PH13-8Mo 0.05 0.10 0.20 0.010 0.008 12.25/13.25 2.00/2.50 7.50/8.50 N 0.01; Al 0.90/1.35
S15500 XM-12 15-5PH 0.07 1.00 1.00 0.040 0.030 14.0/15.5 3.50/5.50 Cu 2.5/4.5; Nb+Ta 0.15/0.45
S15700 632 15-7PH 0.09 1.00 1.00 0.040 0.030 14.00/16.00 2.00/3.00 6.50/7.75 Al 0.75/1.50
S17400 630 17-4PH 0.07 1.00 1.00 0.040 0.030 15.00/17.50 3.00/5.00 Cu 3.00/5.00; Nb+Ta 0.15/0.45
S17600 635 0.08 1.00 1.00 0.040 0.030 16.00/17.50 6.00/7.50 Al 0.40; Ti 0.40/1.20
S17700 631 17-7PH 0.09 1.00 1.00 0.040 0.030 16.00/18.00 6.50/7.75 Al 0.75/1.50
S35000 633 0.07/0.11 0.50 0.50/1.25 0.040 0.030 16.00/17.00 2.50/3.25 4.00/5.00 N 0.07/0.13
S35500 634 0.10/0.15 0.50 0.50/1.25 0.040 0.030 15.00/16.00 2.50/3.25 4.00/5.00 N 0.07/0.13
S41000 51410 410 0.08/0.15 1.00 1.00 0.040 0.030 11.5/13.5 0.75
S41040 XM-30 0.18 1.00 1.00 0.040 0.030 11.0/13.0 Nb 0.05/0.30
S41400 51414 414 0.15 1.00 1.00 0.040 0.030 11.5/13.5 1.25/2.50
S41500 F6NM 0.05 0.60 0.50/1.00 0.030 0.030 11.5/14.0 0.50/1.00 3.5/5.5
S41600 51416 416 0.15 1.00 1.25 0.060 0.15 min 12.0/14.0
S41610 XM-6 (416 Plus X) 0.15 1.00 1.50/2.50 0.06 0.15 min 12.0/14.0
S41623 51416Se 416Se 0.15 1.00 1.25 0.060 0.060 12.0/14.0 Se 0.15 min
S42000 51420 420 0.15 min 1.00 1.00 0.040 0.030 12.0/14.0
S42010 Trim Rite 0.15/0.30 1.00 1.00 0.040 0.030 13.5/15.00 0.40/0.85 0.35/0.85
S42020 51420F 420F 0.30/0.40 1.00 1.25 0.060 0.15 min 12.0/14.0 0.50 Cu 0.60
S42023 51420FSe 420FSe 0.20/0.40 1.00 1.25 0.060 0.060 12.0/14.0 Se 0.15 min    Cu 0.60
S42900 51429 429 0.12 1.00 1.00 0.040 0.030 14.0/16.0
S43100 51431 431 0.20 1.00 1.00 0.040 0.030 15.0/17.0 1.25/2.50
S44002 51440A 440A 0.60/0.75 1.00 1.00 0.040 0.030 16.0/18.0 0.75
S44003 51440B 440B 0.75/0.95 1.00 1.00 0.040 0.030 16.0/18.0 0,75
S44004 51440C 440C 0.95/1.20 1.00 1.00 0.040 0.030 16.0/18.0 0.75
S44020 51440F 440F 0.95/1.20 1.00 1.25 0.060 0.15 min 16.0/18.0 0.75 0.50 Cu 0.60
S44023 51440FSe 440FSe 0.95/1.20 1.00 1.25 0.060 0.060 16.0/18.0 Se 0.15 min Cu 0.60
S45000 XM-25 Custom 450 0.05 1.00 1.00 0.030 0.030 14.00/16.00 0.50/1.00 5.00/7.00 Cu 1.25/1.75; Nb 8xC min
S45500 XM-16 Custom 455 0.05 0.50 0.50 0.040 0.030 11.00/12.50 0.50 7.50/9.50 Cu 1.50/2.50; Nb 0.10/0.50    Ti 0.90/1.40
S45503 0.010 0.20 0.50 0.010 0.010 11.00/12.50 0.50 7.50/9.50 Cu 1.50/2.50; Ti 1.00/1.35 Nb 0.10/0.50
S46500 0.02 0.25 0.25 0.015 0.010 11.00/12.50 0.75/1.25 10.75/11.25 Ti 1.50/1.80 N 0.01
S66286 A286 0.08 1.00 2.00 0.040 0.030 13.50/16.00 1.00/1.50 24.0/27.0 Al 0.35; B 0.0010/0.010; Ti 1.90/2.35;          V 0.10/0.50          W 1.90/2.35

 

Related Articles

  1. Related martensitic and precipitation hardening stainless steel grades

Related References

  1. ASTM and SAE-AMS Standards and Specifications for Stainless Steel
  2. ASTM International, West Conshohocken, PA 19428-2959, USA, 2003

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