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Chemical compositions of AISI (ASTM/ASME) and UNS duplex 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. 2205 being UNS S31803 (or S32205)

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, but this is not usually the case with duplex grades.
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.

Standard and super-duplex 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
S31100 XM-26 0.06 1.00 1.00 0.045 0.030 25.0/27.0 6.0/7.0 Ti 0.25
S31200 44LN 0.030 1.00 2.00 0.045 0.030 24.0/26.0 1.20/2.00 5.5/6.5 N 0.14/0.20
S31260 DP3 0.03 0.75 1.00 0.030 0.030 24.0/26.0 2.5/3.5 5.5/7.5 N 0.10./0.30; Cu 0.20/0.80; W 0.10/0.50
S31500 3RE60 0.03 1.4/2.0 1.2/2.0 0.03 0.03 18.0/19.0 2.5/3.0 4.25/5.25 N 0.05/0.10
S31803 2205 0.030 1.00 2.00 0.030 0.020 21.0/23.0 2.5/3.5 4.5/6.5 N 0.08/0.20
S32001 Nitronic 19D 0.030 1.00 4.0/6.0 0.040 0.030 19.5/21.5 0.60 1.00/3.00 N 0.05/0.17; Cu 1.00
S32003 AL 2003 0.030 1.00 2.00 0.030 0.020 19.5/22.5 1.50/2.00 3.0/4.0 N 0.14/0.20
S32101 LDX 2101 0.040 1.00 4.0/6.0 0.040 0.030 21.0/22.0 0.10/0.80 1.35/1.70 N 0.20/0.25; Cu 0.10/0.80
S32202 DX 2202 0.030 1.00 2.00 0.040 0.010 21.5/24.0 0.45 1.00/2.80 N 0.18.0.26
S32205 2205 UR45N 0.030 1.00 2.00 0.030 0.020 22.0/23.0 3.0/3.5 4.5/6.5 N 0.14/0.20
S32304 2304 0.030 1.00 2.50 0.040 0.030 21.5/24.5 0.05/0.60 3.0/5.5 N 0.05/0.20; Cu 0.05/0.60
S32404 Uranus 50 0.04 1.0 2.0 0.030 0.010 20.5/22.5 2.0/3.0 5.5/8.5 N 0.20; Cu 1.0/2.0
S32520 Uranus 52N+ 0.030 0.80 1.50 0.035 0.020 24.0/26.0 3.0/4.0 5.5/8.0 N 0.20/0.35; Cu 0.50/2.00
S32550 Ferralium 255 0.04 1.00 1.50 0.040 0.030 24.0/27.0 2.9/3.9 4.5/6.5 N 0.10/0.25; Cu 1.50/2.50
S32750 2507 0.030 0.80 1.20 0.035 0.020 24.0/26.0 3.0/5.0 6.0/8.0 N 0.24/0.32; Cu 0.50
S32760 Zeron 100 0.030 1.00 1.00 0.030 0.010 24.0/26.0 3.0/4.0 6.0/8.0 N 0.20/0.30; Cu 0.5/1.00; W 0.50/1.00
S32900 329 44L 453S 0.08 0.75 1.00 0.040 0.030 23.0/28.0 1.00/2.00 2.0/5.00
S32906 0.030 0.50 0.80/1.50 0.030 0.030 28.0/30.0 1.50/2.60 5.8/7.5 N 0.30/0.40; Cu 0.80
S32950 7Mo Plus 0.030 0.60 2.00 0.035 0.010 26.0/29.0 1.00/2.50 3.5/5.2 N 0.15/0.35
S39226 0.030 0.75 1.00 0.030 0.030 24.0/26.0 2.50/3.50 5.50/7.50 N 0.10/0.30; Cu 0.20/0.80; W 0.10/0.50
S39274 DP3W 0.030 0.80 1.0 0.030 0.020 24.0/26.0 2.50/3.50 6.0/8.0 N0.24/0.32; Cu 0.20/0.80; W 1.50/2.50
S39277 AF918 0.025 0.80 0.80 0.025 0.002 24.0/26.0 3.0/4.0 6.5/8.0 N 0.23/0.33; Cu 1.2/2.0; W 0.80/1.20
S82011 AL 2102 0.030 1.00 2.0/3.0 0.040 0.020 20.5/23.5 0.10/1.00 1.0/2.0 N 0.15/0.27
S82441 LDX 2404 0.030 0.7 2.5/4.0 0.035 0.005 23.0/25.0 1.00/2.00 3.0/4.5 N 0.20/0.30 Cu 0.10/0.80

Related Articles

  1. Related duplex 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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