1.4057 QT900
- Hardness
- 30 HRC
- Thermal Conductivity
- 25 W/(m·K)
- Elongation
- 10 %
- Chemical Composition
- C: 0.2%, Cr: 16%, Ni: 2%, Mn: 1.5%, Si: 1%, P: 0.04%, S: 0.03%
Other Names
- X17CrNi16-2
- ČSN 17 145
- AISI / SAE 431
- UNS S43100
- JIS SUS431
- AFNOR Z15CN16-02
- SS 2321
- GOST 20Ch17N2
Material Description
**EN 1.4057 / AISI 431 (X17CrNi16-2)** is a martensitic stainless steel offering good corrosion resistance and high mechanical strength. It is commonly supplied in quenched and tempered conditions, typically +QT800 (800–950 MPa) or +QT900 (900–1050 MPa). Despite its stainless-steel classification, its machining behaviour is strongly influenced by its relatively high strength. Cutting tools suitable for medium- to high-strength steels are generally recommended, preferably with sharp geometries suitable for stainless steels to reduce work hardening. Its relatively low thermal conductivity (25 W/m·K) should also be considered when selecting cutting speeds.