Grade 420 Stainless Steel

420 is a martensitic stainless steel, magnetic and hardenable with rust resistant properties. 420 stainless is characterised by having a 0.30-0.40 carbon, and 12.00-14.00% chromium content. This mix of analysis gives our 420 stainless sheet and sections an outstanding corrosion resistance and exceptional wear properties after heat treatment. Superior to 410 and 416 type stainlesses for most applications. 420 stainless steel has good ductility in the annealed condition, but is capable of achieving 57HRC after treatment. Optimal corrosion resistance is realised when 420 is surface ground and polished after hardening.

 420 Stainless Steel  Chemical Analysis wt % 
C Si Mn P S Cr Ni
0.30-0.40 ≤ 1.00 ≤ 1.00 ≤ 0.04 ≤ 0.03 12.00-14.00 ≤ 0.50

Applications for 420 Stainless Steel

Dental and surgical instruments cutlery pump shafts gear pinions, cams, various hand tools, straight edges and scissors

Not recommended for high pressure vessels.

Soft Annealing 420 Stainless steel

Heat to 730-780°C. Cool slowly in air. 

Structure is ferrite with spherical carbides.

Machineability of 420 Stainless steel

Good machining characteristics due to the addition of Sulphur.

High speeds and feeds producing short brittle chips

 420 Stainless Steel Mechanical Properties at ambient temperature 

 Condition annealed. Quenched and tempered 850°C

 0.2% Proof Stress: 600 Nmm²

 Tensile Strength: 800 - 9500 Nmm²

 Elongation: 12% 

 Hardness HB Max 230

Forging 420 Stainless steel

Hot forming temperature 850-1100°C. Slow cool

Hardening 420 Stainless steel

Harden from a temperature 980-1030°C

Follow by oil or air quenching.

Hardness after quenching 52 HRC

Tempering 420 Stainless steel

Tempering temperature 100-200°C

Heat Treatment Advise of 420 Stainless steel

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 work piece transfer facilities. Please consult your heat treatment provider for full guidance for the heat treatment of 420 Stainless steel

Corrosion resistance 420 Stainless steel

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

 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): 30.0

 Electric resistivity.  (Ohm mm²/m): 0.60

 Specific heat capacity.  (J/g.K): 0.46

 Magnetisable. Yes

Welding of 420 Stainless steel

Not commonly welded due to its air hardening characteristics. Welding may possibly be performed after preheating to 150-205°C with the post welding tempering at temperature for 2 hours. Recommendation of specialist advice to be sought

Cold working of 420 Stainless steel

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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