420 Stainless Steel
420 is martensitic stainless steel that provides good corrosion resistance similar to 410 plus increased strength and hardness.

420 stainless steel is a martensitic higher carbon version of types 410 and 416 stainless.
Type 420 is martensitic steel that provides good corrosion resistance similar to 410 with the benefit of increased strength and hardness. It is magnetic in both the annealed and hardened conditions.
Applications include cutlery, surgical and dental instruments, straight edges, and firearms. We supply type 420 in bar, wire, and billets, contact us for the best prices.
420 Stainless Steel Properties and Specifications
420 stainless steel is a hardenable, martensitic stainless steel with corrosion resistance similar to Type 410. It has a higher carbon content to increase strength and hardness over Type 410. Maximum corrosion resistance only in the fully hardened condition or fully hardened and stress relieved condition. Never used in the annealed condition.
420 stainless steel is available in:
- Bar
- Wire
- Billets
Type 420 Stainless Steel (bar, wire, and billets) is covered by the following specifications:
- QQ-W-423A
- MIL-S-862B
- MIL-S-8142
- MIL-W-17481A
- AMS 5621
- ASTM A276-67
- ASTM A314-63
- ASTM A580-67
- QQ-S-763D
- Specified for a wide variety of applications where good corrosion and hardness in the range of C50 to C54 is required.
- Applications include cutlery, surgical and dental instruments, scissors, tapes, and straight edges, gauges, needle valves, ball check valves, gear shafts, cams, pivots, ball bearings, and hand tools.
- Not normally used at temperatures exceeding 800° F due to rapid softening and loss of corrosion resistance.
420 Stainless Steel Composition & Properties
Property
Type 420%
Carbon
.15 max
Manganese
1.00 max
Silicon
1.00 max
Phosphorus
.040 max
Sulfur
.030 max
Chromium
12.0 – 14.0
Mechanical Properties
Property
Annealed
Hardened
Stress Relieved
Ultimate Tensile Strength, psi
95,000
230,000
.02% Yield Strength, psi
50,000
195,000
Elongation, % in 2?
25
8
Rockwell Hardness
B92
C54
C50
Reduction of area, %
55
25
Impact Strength Izod V-Notch, ft-lbs
30
5-15
Machinability
- Type 420 Stainless Steel machines like a high carbon steel.
- Chips are tough and stringy.
- Carbide cutting tools are recommended because this alloy has an abrasive action on tools.
- For parts that require extensive machining, the two free-machining versions, Type 430 and Type 430F Se offer fabrication economies.
Formability
- If annealed for maximum softness, Type 420 can be moderately cold formed, and cold headed.
- It can be readily forged and hot-headed.
- Preheating prior to hot working insures the best results.
- Because this steel is air hardening, all hot worked parts should be furnace cooled to prevent cracking.
420 Stainless Steel Heat Treatment
- ANNEALING: For maximum softness, heat uniformly to 1600-1650° F and cool down slowly in the furnace.
- HARDENING: Preheat, then heat to 1800-1950° F, soak at temperature and air cool or quench in warm oil.
- STRESS RELIEVING: Heat at 300-800° F for 1 to 3 hours, cool in air or quench in oil or water.
Corrosion Resistance
- 420 stainless steel has its full corrosion resistance only in the hardened or hardened and stress relieved conditions.
- In these conditions its corrosion resistance is similar to Type 410. Type 420 resists corrosion by the atmosphere, fresh water, mine water, steam, carbonic acid, crude oil, gasoline, perspiration, alcohol, ammonia, mercury, sterilizing solutions, soaps, and other similar corrosive media.
Weldability
- Because of the air hardening characteristics of Type 420, it has only fair weldability and is seldom welded.
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