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Chemical compositions of AISI (ASTM/ASME) and UNS austenitic 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 304, 430 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. 304 being UNS S30400, 304L being UNS S30403

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 304. 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.

There are some differences in the composition ranges for some grades between flat and long products. This is due to the harmonisation process which is aimed to bring US and European compositions into line. This process is more advanced for flat products than for long. Consequently, there will be small differences until this process is complete. Where there is a different composition depending on product form, both compositions are 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.

Standard 300 series austenitic 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
S30100 30301 301 0.15 1.00 2.00 0.045 0.030 16.0/18.0 – 6.0/8.0 N 0.10
S30103 – 301L 0.03 1.00 2.00 0.045 0.030 16.0/18.0 – 6.0/8.0 N 0.20
S30153 – 301LN 0.03 1.00 2.00 0.045 0.030 16.0/18.0 – 6.0/8.0 N 0.07/0.20
S30200 30302 302 0.15 0.75 2.00 0.045 0.030 17.0/19.0 – 8.0/10.0 N 0.10
S30215 30302B 302B 0.15 2.00/3.00 2.00 0.045 0.030 17.0/19.0 – 8.0/10.0 –
S30300 30303 303 0.15 1.00 2.00 0.20 0.15 min 17.0/19.0 – 8.0/10.0
S30310 – XM-5 (303Plus x) 0.15 1.00 2.50/4.50 0.20 0.25 min 17.00/19.00 – 7.00/9.00 –
S30323 30303Se 303Se 0.15 1.00 2.00 0.20 0.060 17.0/19.0 – 8.0/10.0 Se 0.15 min
S30330 – 303Cu 0.15 1.00 2.00 0.15 0.10 min 17.0/19.0 – 6.0/10.0 Cu 2.5/4.0; Se 0.10
S30400 30304 304 0.07 0.75 2.00 0.045 0.030 17.5/19.5 – 8.0/10.5 N 0.10
S30400 A276 for bar 30304 304 0.08 1.00 2.00 0.045 0.030 18.0/20.0 8.0/11.0
S30403 30304L 304L 0.030 0.75 2.00 0.045 0.030 17.5/19.5 – 8.0/12.0 N 0.10
S30403 A276 for bar 30304L 304L 0.030 1.00 2.00 0.045 0.030 18.0/20.0 8.0/12.0
S30430 – 302HQ 0.03 1.00 2.00 0.045 0.030 17.0/19.0 – 8.0/10.0 Cu 3.0/4.0
S30452 – XM-21 (304HN) 0.08 1.00 2.00 0.045 0.030 18.0/20.0 – 8.00/10.00 N 0.16/0.30
S30453 – 304LN 0.030 0.75 2.00 0.045 0.030 18.0/20.0 – 8.0/12.0 N 0.10/0.16
S30454 – – 0.03 1.00 2.00 0.045 0.030 18.0/20.0 – 8.0/11.0 N 0.16/0.30
S30500 30305 305 0.12 0.75 2.00 0.045 0.030 17.0/19.0 – 10.5/13.0 –
S30800 30308 308 0.08 1.00 2.00 0.045 0.030 19.0/21.0 – 10.0/12.0 –
S31600 30316 316 0.08 0.75 2.00 0.045 0.030 16.0/18.0 2.00/3.00 10.0/14.0 N 0.10
S31603 30316L 316L 0.030 0.75 2.00 0.045 0.030 16.0/18.0 2.00/3.00 10.0/14.0 N 0.10
S31635 – 316Ti 0.08 0.75 2.00 0.045 0.030 16.0/18.0 2.00/3.00 10.0/14.0 Ti 5x (C+N) / 0.70

N 0.10
S31640 – 316Cb 0.08 0.75 2.00 0.045 0.030 16.0/18.0 2.00/3.00 10.0/14.0 Nb 10x C / 1.10

N 0.10
S31653 – 316LN 0.030 0.75 2.00 0.045 0.030 16.0/18.0 2.00/3.00 10.0/14.0 N 0.10/0.16
S31700 30317 317 0.08 0.75 2.00 0.045 0.030 18.0/20.0 3.0/4.0 11.0/15.0 N 0.10
S31703 – 317L 0.030 0.75 2.00 0.045 0.030 18.0/20.0 3.00/4.00 11.0/15.0 N 0.10
S31725 – 317LM 0.030 0.75 2.00 0.045 0.030 18.0/20.0 4.0/5.0 13.5/17.5 N 0.20
S31726 – 317LMN 0.030 0.75 2.00 0.045 0.030 17.0/20.0 4.0/5.0 13.5/17.5 N 0.10/0.20
S31753 – 317LN 0.030 0.75 2.00 0.045 0.030 18.0/20.0 3.0/4.0 11.0/15.0 N 0.10/0.22
S32100 30321 321 0.08 0.75 2.00 0.045 0.030 17.0/19.0 – 9.0/12.0 Ti 5 x C min/0.70

N 0.10
S34700 30347 347 0.08 0.75 2.00 0.045 0.030 17.0/19.0 – 9.0/13.0 Nb+Ta 10 x C min/1.0
S34720 – 347F 0.08 1.00 2.00 0.040 0.18/0.35 17.00/19.00 0.75 9.00/12.00 Nb 10xC / 1.10; Cu 0.75; Ta 0.05
S34723 – 347FSe 0.08 1.00 2.00 0.11/0.17 0.030 17.00/19.00 0.75 9.00/12.00 Nb 10xC / 1.10; Cu 0.75; Se 0.15/0.35; Ta 0.05
S34800 30348 348 0.08 0.75 2.00 0.045 0.030 17.0/19.0 – 9.00/13.0 Nb+Ta 10 x C / 1.00; Ta:0.10 max; Co 0.20
S38400 30384 384 0.04 1.00 2.00 0.045 0.030 15.0/17.0 – 17.0/19.0 –

Standard 200 series austenitic 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
S20100 30201 201 0.15 1.00 5.5/7.5 0.060 0.030 16.0/18.0 – 3.5/5.5 N 0.25
S20103 – – 0.03 0.75 5.5/7.5 0.045 0.030 16.0/18.0 – 3.5/5.5 N 0.25
S20153 – – 0.03 0.75 6.4/7.5 0.045 0.015 16.0/17.5 – 4.0/5.0 N 0.10/0.25; Cu 1.00
S20161 – Gall-Tough 0.15 3.0/4.0 4.0/6.0 0.040 0.040 15.0/18.0 – 4.0/6.0 N 0.08/0.20
S20162 – – 0.15 2.5/4.5 4.0/8.0 0.040 0.040 16.5/21.0 0.50/2.50 6.0/10.0 N 0.05/0.25
S20200 30202 202 0.15 1.00 7.5/10.0 0.060 0.030 17.0/19.0 – 4.0/6.0 N 0.25
S20300 – XM-1 (203EZ) 0.08 1.00 5.0/6.5 0.04 0.18/0.35 16.0/18.0 – 5.0/6.5 Cu 1.75/2.25
S20400 – – 0.030 1.00 7.0/9.0 0.040 0.030 15.0/17.0 – 1.5/3.0 N 0.15/0.30
S20500 – 205 0.12/0.25 1.00 14.0/15.5 0.060 0.030 16.5/18.0 – 1.0/1.7 N 0.32/0.40
S20910 – XM-19 (Nitronic 50) 0.06 0.75 4.0/6.0 0.040 0.030 20.5/23.5 1.50/3.00 11.5/13.5 Nb 0.10/0.30; V 0.10/0.30
S21400 – XM-31 (Tenelon) 0.12 0.30/1.00 14.0/16.0 0.045 0.030 17.0/18.5 – 1.00 –
S21460 – XM-14 0.12 0.75 14.0/16.0 0.060 0.030 17.0/19.0 – 5.0/6.0 N 0.35/0.50
S21600 – XM-17 (216) 0.08 0.75 7.5/9.0 0.045 0.030 17.5/22.0 2.00/3.00 5.0/7.0 N 0.25/0.50
S21603 – XM-18 (216L) 0.03 0.75 7.5/9.0 0.045 0.030 17.5/22.0 2.00/3.00 5.0/7.0 N 0.25/0.50
S21800 – Nitronic 60 0.10 3.5/4.5 7.0/9.0 0.060 0.030 16.0/18.0 – 8.0/9.0 N 0.08/0.18
S21900 – 21-6-9 (Nitronic 40) 0.08 1.00 8.00/10.00 0.045 0.030 19.0/21.50 – 5.5/7.5 N 0.15/0.40
S21904 – XM-11 (Nitronic 40) 0.04 0.75 8.0/10.0 0.060 0.030 19.0/21.5 – 5.5/7.5 N 0.15/0.40
S24000 – XM-29 (Nitronic 33) 0.08 0.75 11.5/14.5 0.060 0.030 17.0/19.0 – 2.3/3.7 N 0.20/0.40
S24100 – 18-2Mn (Nitronic 32) 0.15 1.00 11.0/14.0 0.045 0.030 16.5/19.0 – 0.50/2.50 N 0.20/0.45
S28200 – 18-18 Plus 0.15 1.00 17.0/19.0 0.045 0.030 17.0/19.0 0.75/1.25 – N 0.40/0.60; Cu 0.75/1.25

Special austenitic 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
N08020 – 20Cb-3 0.07 1.00 2.00 0.045 0.035 19.0/21.0 2.00/3.00 32.0/38.0 Cu 3.0/4.0; Nb 8xC / 1.00
N08024 – 20Mo-4 0.03 0.50 1.00 0.035 0.035 22.5/25.0 3.5/5.0 35.0/40.0 Cu 0.50/1.50; Nb+Ta 0.15/0.35
N08026 – 20Mo6 0.03 0.50 1.00 0.03 0.03 22.00/26.00 5.00/6.70 33.0/37.20 Cu 2.00/4.00; N 0.10/0.16
N08028 – Sanicro28 0.030 1.0 2.50 0.030 0.030 26.0/28.0 3.0/4.0 29.5/32.5 Cu 0.6/1.4
N08366 – AL-6X 0.03 1.00 2.00 0.040 0.030 20.0/22.0 6.0/7.0 23.5/25.5 –
N08367 – AL-6XN 0.030 1.00 2.00 0.040 0.030 20.0/22.0 6.0/7.0 23.5/25.5 Cu 0.75; N 0.18/0.25
N08700 – JS700 0.04 1.00 2.00 0.040 0.030 19.0/23.0 4.3/5.0 24.0/26.0 Cu 0.50; Nb 8xC / 0.40
N08904 – 904L 0.020 1.00 2.00 0.045 0.035 19.0/23.0 4.0/5.0 23.0/28.0 Cu 1.0/2.0

N 0.10
N08925 – 1925hMo 0.020 0.50 1.0 0.045 0.030 19.0/21.0 6.0/7.0 24.0/26.0 Cu 0.80/1.50 N 0.10/0.20
N08926 – – 0.020 0.50 2.00 0.030 0.010 19.0/21.0 6.0/7.0 24.0/26.0 Cu 0.50/1.50 N 0.15/0.25
S30600 – Cronifer 1815 LCSi 0.018 3.7/4.3 2.00 0.020 0.020 17.0/18.5 0.20 14.0/15.5 Cu 0.50
S30601 – – 0.015 5.0/5.6 0.50/0.80 0.030 0.013 17.0/18.0 0.20 17.0/18.0 Cu 0.05; N 0.35
S31050 – 310MoLN 0.020 0.50 2.00 0.030 0.010 24.0/26.0 1.60/2.60 20.5/23.5 N 0.09/0.15
S31254 – 254SMO 0.020 0.80 1.00 0.030 0.010 19.5/20.5 6.0/6.5 17.5/18.5 Cu 0.50/1.00; N 0.18/0.22
S31266 – – 0.030 1.00 2.0/4.0 0.035 0.020 23.0/25.0 5.2/6.2 21.0/24.0 Cu 1.00/2.50; N 0.35/0.60; W 1.50/2.50
S31277 – – 0.020 0.50 3.00 0.030 0.010 20.5/23.0 6.5/8.0 26.0/28.0 Cu 0.5/1.50; N 0.30/0.40
S32050 – – 0.030 1.00 1.50 0.035 0.020 22.0/24.0 6.0/6.8 20.0/23.0 N 0.21/0.32

Cu 0.40
S32615 – – 0.07 4.8/6.0 2.00 0.045 0.030 16.5/19.5 0.30/1.50 19.0/22.0 Cu 1.50/2.50
S32654 – 654SMO 0.020 0.50 2.0/4.0 0.030 0.005 24.0/25.0 7.0/8.0 21.0/23.0 Cu 0.30/0.60; N 0.45/0.55
S34565 – Nirosta 4565S 0.030 1.00 5.0/7.0 0.030 0.010 23.0/25.0 4.0/5.0 16.0/18.0 N 0.40/0.60; Nb 0.10
S35135 – – 0.08 0.60/1.00 1.00 0.045 0.015 20.0/25.0 4.0/4.8 30./38.0 Ti 0.40/1.00
S38100 – XM-15 (18-18-2) 0.08 1.50/2.50 2.00 0.030 0.030 17.0/19.0 – 17.5/18.5 –
S38815 – – 0.030 5.5/6.5 2.00 0.040 0.020 13.0/15.0 0.75/1.50 13.0/17.0 Cu 0.75/1.50; Al 0.30

Related Articles

  1. Related austenitic 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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