High Alloy ( >10%)
Stainless (>11% Cr)
- Oxygen in environment reacts with Chromium in metal to form a corrosion resistant Chromium-Oxide layer.
- Corrosion resistance measured by Pitting Resistance Equivalent Number (PREN).
- Calculated as Cr + 3.3Mo+16N - Mn
- 16 is corrosion resistant to tap water
- 23 is incidentally resistant to sea water
- 32 is dive resistant to sea water
Ferritic
- Plain chromium stainless steel
| EN | # | AISI | UNS | PREN |
|---|
| X2CrNi12 | 1.4003 | | S40977 | |
| X2CrTi12 | 1.4512 | 409 | S40900 | |
| X6CrNiTi12 | 1.4516 | | | |
| X6Cr13 | 1.4000 | 410S | S41008 | |
| X6CrAl13 | 1.4002 | 405 | S40500 | |
| X6Cr17 | 1.4016 | 430 | S43000 | 18 |
| X3CrTi17 | 1.4510 | 439 | S43035 | |
| X3CrNb17 | 1.4511 | 430N | | |
| X6CrMo17-1 | 1.4113 | 434 | S43400 | |
| X2CrMoTi18-2 | 1.4521 | 444 | S44400 | 24 |
Martensitic (Cr 12-18% | C 0.2-1.2%)
- Like Ferritic, but with more Carbon (0.2% - 1.2%)
- Carbon makes it heat-treatable for added strength
- Usually poor for welding (some ‘utility grades’ are ok though)
| EN | # | AISI | UNS | PREN | Body |
|---|
| X30CrMoN15-1 | 1.4108 | | | | x |
| X12Cr13 | 1.4006 | 410 | S41000 | | |
| X20Cr13 | 1.4021 | 420 | S42000 | | |
| X30Cr13 | 1.4028 | 420 | S42000 | | |
| X3CrNiMo13-4 | 1.4313 | | S41500 | | |
| X4CrNiMo16-5-1 | 1.4418 | | | | |
| X5CrNiCuNb16-4 | 1.4542 | | S17400 | | |
| X2CrMoTi18-2 | 1.4521 | 444 | S44400 | | x |
Austenitic
- Has Nickel
- Most commonly used, especially in on-body applications like watches
| EN | # | AISI | UNS | PREN | Body |
|---|
| X2CrNiMnMoNNb21-16-5-3 | 1.3964 | XM-19 | S20910 | 34 | x |
| X10CrNi18-8 | 1.4310 | 301 | S30100 | | |
| X2CrNi18-9 | 1.4307 | 304L | S30403 | | |
| X2CrNi19-11 | 1.4306 | 304L | S30403 | | |
| X2CrNiN18-10 | 1.4311 | 304LN | S30453 | | |
| X5CrNi18-10 | 1.4301 | 304 | S30400 | | x |
| X6CrNiTi18-10 | 1.4541 | 321 | S32100 | | |
| X4CrNi18-12 | 1.4303 | 305 | S30500 | | |
| X2CrNiMo17-12- | 1.4404 | 316L | S31603 | | x |
| X2CrNiMoN17-11-2 | 1.4406 | 316LN | S31653 | | |
| X5CrNiMo17-12-2 | 1.4401 | 316 | S31600 | 24 | |
| X6CrNiMoTi17-12-2 | 1.4571 | 316Ti | S31635 | | |
| X2CrNiMo17-12-3 | 1.4432 | 316L | S31603 | | |
| X2CrNiMo18-4-3 | 1.4435 | 316L | S31603 | 26 | x |
| X2CrNiMoN17-13-5 | 1.4439 | 317L | | | |
| X1NiCrMoCu25-20-5 | 1.4539 | 904L | N08904 | 34 | x |
Duplex
- Mixed ferrite/austentic structure.
- Higher chromium, lower nickel than Austenitic
- Contains nitrogen.
- High strength, weldable
| EN | # | AISI | UNS | PREN |
|---|
| X2CrNiN22-2 | 1.4062 | | S32202 | 27 |
| X2CrMnNiMoN21-5-3 | 1.4482 | | S32001 | |
| X2CrMnNiN21-5-1 | 1.4162 | | S32101 | 26 |
| X2CrNiN23-4 | 1.4362 | | S32304 | 26 |
| X2CrNiMoN12-5-3 | 1.4462 | | S31803 | 35 |
Low Alloy
Low-carbon
Medium-carbon
High-carbon