1.4057 – AISI 431 – X17CrNi16.2 - UNS S43100
Description
Grade 1.4057 is a martensitic steel with good corrosion resistance in moderately aggressive environments and high mechanical properties after hardening with a hardness up to 46HRC. It is generally produced in air (EAF+AOD) but chemistry can be modified to improve machinability and cleanliness can be improved using ESR remelted process to increase corrosion resistance.
Stainless has several sources in stock as well as different formats or product states to best suit your processing needs. This product can also be made to measure or cut into slabs by our service centres.
Main applications
Due to its corrosion resistance and high hardness in the hardened condition, the grade is used in the manufacture of medical instruments, cutlery, chemistry, defense or food industry. The material is available in the annealed condition as well as in the QT (quenched and tempered) condition.
Metallurgy
The melting processes combined with the transformation processes allow a homogeneous microstructure to be obtained. In the processed state, the microstructure consists of martensite and undissolved carbides (see photo below):
Machinability
Forgeability
The grade can be hot forged in the temperature range 950/1180°C.
Polishability
Polishable grade in the treated condition with a structure consisting of martensite and carbides. The laser marking can lead to a reduction in corrosion resistance, especially in the event of overheating.
Typical heat treatments
Hardening is carried out from 1000/1050°C followed by tempering from 180°C, avoiding the 400-600°C zone.
Corrosion resistance
The grade has good resistance to general corrosion in the treated condition (46HRC). Its resistance to corrosion in non-chloride environments is even better when the surfaces are polished, pickled and passivated. Corrosion resistance is strongly degraded in the annealed condition or after welding, which needs to be highly controlled. If the grade is optimized for machinability with a higher sulfur content, corrosion resistance will be reduced. 1.4057 corrosion resistance is higher than 1.4021 or 1.4028 corrosion resistance.
Standard Sizes
Round bars in annealed or QT condition depending on the diameter – Peeled or ground surface
Customized flat bars, rolled or cutted from forged blocks
Other formats: please contact us