Stainless Steels

Stainless steels got their name when they were initially used in the manufacture of cutlery - literally, they would not stain. It is better to consider stainless steels as metals that are particularly resistant to corrosion.

These kinds of metals are iron alloys that contain a minimum of 10.5% Chromium. This element forms a self-healing very tight transparent layer over a steel surface and protects it from corrosion by stopping further oxidation. In addition to this alloying element, others are added to change the structure of the metal and give it different properties, for example,

  • Abrasion Resistance
  • Appearance
  • Corrosion Resistance
  • Oxidation Resistance at High Temperatures
  • Strength and Ductility at Cryogenic Temperatures
  • Strength at Elevated Temperatures
  • Machineability

Commonly metal and non-metal elements are added to impart various properties:

  • Aluminium - improves scaling resistance.
  • Carbon - increases strength, but can reduce corrosion resistance.
  • Chromium - forms a self-healing transparent film to protect against corrosion.
  • Colombium - combines with Carbon to reduce intergranular corrosion.
  • Copper - increases resistance to certain corrosive environments.
  • Manganese - improves hot working properties and promotes austenite stability.
  • Molybdenum - increases corrosion resistance and strength at high temperatures and useful in chloride environments.
  • Nickel - increases ductility, high temperature strength and corrosion resistance, especially in marine environments.
  • Silicon - increases scaling resistance and imparts carburizing resistance.
  • Titanium - combines with Carbon to reduce intergranular corrosion.

The following are chemical composition tables for Stainless Steels. Please note that these are not standards but grade composition ranges only.

All information is given purely for reference purposes

Austenitic Stainless Steels

All 200 and 300 series stainless steels contain between 15-30% Chromium and 2-20% Nickel to give the materials good surface quality, formability and increased corrosion resistance.

It must be noted that when they are cold worked, they can become slightly magnetic.

Austenitic Series 300 Grade Stainless Steels

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 -

Austenitic Series 200 Stainless Steel 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

Special ferritic 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
S32803 - Cronifer 2803Mo 0.015 0.55 0.50 0.020 0.0035 28.0/29.0 1.80/2.50 3.0/4.0 N 0.020; (C+N) 0.030; Nb 0.15/0.50
S43035 - 435 0.030 1.00 1.00 0.040 0.030 17.0/19.0 - 0.50 Ti [0.20+4(C+N)] / 1.10; Al 0.15
S43903 51439LL 439LL 0.014 1.00 1.00 0.040 0.030 17.0/19.0 - 0.50 Ti [0.20+4(C+N)] / 1.10; Al 0.15; N:0.04
S43932 - 441 0.030 1.00 1.00 0.040 0.030 17.0/19.0 - 0.50 N 0.030; (Ti+Nb) [0.20+4(C+N)] / 0.75; Al 0.15
S43940 - - 0.030 1.00 1.00 0.040 0.015 17.5/18.5 - - Ti 0.10/0.60; Nb [0.30+(3xC)] min
S44400 - 444 18Cr-2Mo 0.025 1.00 1.00 0.040 0.030 17.5/19.5 1.75/2.50 1.00 N 0.035; (Ti+Nb)[0.20+4(C+N)] / 0.80
S44500 - - 0.020 1.00 1.00 0.040 0.012 19.0/21.0 - 0.60 N 0.03; Cu 0.30/0.60; Nb 10x(C+N) / 0.80
S44626 - XM-33 (26-1Ti) 0.06 0.75 0.75 0.040 0.020 25.0/27.0 0.75/1.50 0.50 N 0.04; Cu 0.20; Ti 0.20/1.00 Ti 7x(C+N) min 
S44627 - XM-27 0.010 0.40 0.40 0.020 0.020 25.0/27.0 0.75/1.50 0.50 N 0.015; Cu 0.20; Nb 0.05/0.20; (Ni+Cu) 0.50
S44635 - Nu Monit (25-4-4) 0.025 0.75 1.00 0.040 0.030 24.5/26.0 3.5/4.5 3.5/4.5 N 0.035; (Ti+Nb){0.20+4(C+N)] / 0.80
S44660 - Sea-cure (26-3-3) 0.030 1.00 1.00 0.040 0.030 25.0/28.0 3.0/4.0 1.0/3.5 N 0.040; (Ti+Nb)0.20 / 1.00; (Ti+Nb) [6x(C+N)] min
S44700 - 29-4 0.010 0.20 0.30 0.025 0.020 28.0/30.0 3.5/4.2 0.15 N 0.020; Cu 0.15; (C+N) 0.025
S44735 - - 0.030 1.00 1.00 0.040 0.030 28.0/30.0 3.6/4.2 1.00 N 0.045; (Ti+Nb)0.20/1.00; (Ti+Nb) 6x (C+N) min
S44800 - 29-4-2 0.010 0.20 0.30 0.025 0.020 28.0/30.0 3.5/4.2 2.00/2.50 N 0.020; Cu 0.15; (C+N) 0.025
S46800 - - 0.030 1.00 1.00 0.040 0.030 18.0/20.0 - 0.50 N 0.030; Ti 0.07/0.30; Nb 0.10/0.60; (Ti+Nb) [0.20+4(C+N)] / 0.80

Martensitic and Precipitation Hardening Stainless Steels

These types of stainless steels usually contain between 11.5 to 18% chromium and have a higher carbon content that Ferritic Steels. This makes them particularly heat treatable to increase their hardness and strength.

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

The data given is not intended to replace that shown in individual standards to which reference should always be made.