Designation by Standards

1.4057 X17CrNi16-2 X17CrNi16-2 431 SUS431 20Ch17N2

Chemical Composition (in weight %)

C Si Mn Cr Mo Ni V W Others
0.18 0.40 0.60 16.00 - 2.30 - - -

1.4057 is a martensitic stainless combining excellent impact strength at high hardness levels with the best corrosion resistance of any martensitic stainless steels. Steel with high polishability. For application up to working temperature 500oC.

1.4057 has been successfully used in a variety of aircraft and general industrial applications. These include fasteners, shafts, bolts, valve components and chemical equipment, components for dairies, machine building and paper industry.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 216
Density [g/cm3]: 7.70
Thermal conductivity [W/m.K]: 25.0
Electric resistivity [Ohm mm2/m]: 0.70
Specific heat capacity[J/g.K]: 0.46

Modulus of Elasticity [103 N/mm2]

20oC 200oC 400oC
216 205 190

Coefficient of Linear Thermal Expansion 10-6 oC-1

20-100oC 20-200oC 20-300oC 20-400oC 20-500oC 20-600oC 20-700oC
11.2 11.5 11.7 11.9 12.0 12.1 12.0

Soft Annealing
Heat to 660-750oC, cool slowly in furnace. This will produce a maximum Brinell hardness of 295.

Harden from a temperature of 980-1030oC followed by oil or air quenching. Hardness after quenching is about 47 HRC.

Tempering temperature: For Q+T 800: 750-800oC. For Q+T 900: 600-650oC.

0.2 % Proof Stress (N/mm2) at Elevated Temperatures

Condition 100oC 150oC 200oC 250oC 300oC 350oC 400oC
Q+T 800 515 495 475 460 440 405 355
Q+T 900 565 525 505 490 470 430 375

Hot forming temperature: 1100-800oC, slow cooling.

In the fully annealed condition, 431 will gall and build up on the tools. Good surface finishes are not easily obtained.

Corrosion Resistance
431 is superior to all other martensitic grades in terms of corrosion resistance. Will resist dilute acids and alkalis, neutral and basic salts, food acids, fresh water and atmosphere.

Most electric welding procedures have proven successful with 431 stainless. Filler metal should be AWS E/ER410.To avoid cracking, pre-heat the workpiece to 204-316oC. After air cooling, treat at 649oC to reattain maximum properties.

Embittlemnt: It must be in mind that the temperature range between 425 and 525oC must be avoided owing to embritllement at 475oC.

Cold working
This alloy is easily drawn, spun, headed, sheared and bent compared with other stainless steels.

All technical information is for reference only.