Grade 420S37 - 420 Stainless Steel

420S37 stainless steel is a martensitic grade of stainless. It is magnetic and hardenable with rust resistant properties. 420S37 stainless is characterised by having a 0.20-0.28 carbon, and 12-14% chromium content. This mix of analysis gives 420S37 stainless steel an outstanding corrosion resistance and exceptional wear properties after heat treatment. Superior to 410 and 416 for most applications. 420S37 stainless steel has good ductility in the annealed condition, but is capable of achieving 52HRC after treatment. Optimal corrosion resistance is realised when 420S37 is surface ground and polished after hardening.

 420S37 - 420 Stainless Steel  Chemical Analysis wt % 
C Si Mn P S Cr Ni
0.20-0.28 ≤ 1.00 ≤ 1.00 ≤ 0.04 ≤ 0.015 12.0-14.0 ≤ 1.00

Applications for 420S37

Dental and surgical instruments cutlery, pump components, shafts, plastic moulds, gear pinions, cams and various hand tools

Not recommended for high pressure vessels

Soft Annealing 420S37

Heat to 730-810°C. Cool slowly in air. 

Structure is ferrite with spherical carbides

Machineability of 420S37

Good machining characteristics due to the addition of Sulphur.

High speeds and feeds producing tough, stringy chips

 420S37 - 420 Stainless Mechanical Properties at ambient temperature 

 Condition annealed. Quenched and tempered 850°C

 0.2% Proof Stress: 650 Nmm²

 Tensile Strength: 800 - 950 Nmm²

 Elongation: 13% 

 Notch Impact Energy: (ISO-V) (J) 20

 Hardness HB Max 230

Forging 420S37

Hot forming temperature 850-1100°C. Slow cool

Hardening 420S37

Harden from a temperature 950-1050°C

Follow by oil or air quenching.

Tempering 420S37

Tempering temperature 150-250°C

Heat Treatment Advise of 420S37

Treatment temperatures, including the rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each 420 stainless steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium, and workpiece transfer facilities. Please consult your heat treatment provider for full guidance for heat treatment of 420S37 stainless steel.

Corrosion resistance 420S37

Hardened condition realises resistance to atmosphere, fresh, dilute acids and alkalise, fresh water and fruit and vegetable juices

 420S37 - 420 Stainless Steel  Physical properties  

 Average values at ambient temperature

 Modulus of elasticity.  (10³ x N/mm²) : 216

 Density.  (g/cm³): 7.73

 Thermal conductivity.  (W/m.K): 31.0

 Electric resistivity.  (Ohm mm²/m): 0.60

 Specific heat capacity.  (J/g.K): 0.47

 Magnetisable. Yes

Welding of 420S37

Not commonly welded due to its air-hardening characteristics. Welding may possibly be performed after preheating to 149-204°C with the post-welding tempering at temperature for 2 hours. Recommendation of specialist advice to be sought

Cold working of 420S37

The material will withstand only minor cold work. Radical forming operations will result in cracking


The information and data presented herein are typical or average values and are not a guarantee of maximum or minimum values. Applications specifically suggested for material described herein are made solely for the purpose of illustrations to enable the reader to make their own evaluations. They are not intended to either express or imply the suitability for these or any other purposes 

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