420 Stainless Steel

420 (UNS S42000) martensitic stainless steel is best for applications requiring outstanding hardness and good corrosion resistance.

420 stainless steel is hardenable steel that contains the minimum amount of 12% chromium which gives it sufficient corrosion resistance properties. 420 stainless steels possess higher carbon content compared to 410 stainless steels that are designed for hardness and high strength characteristics.

Grade 420 stainless steels are hardened with heat treatment. It exhibits very good ductility in the annealed state and great corrosion resistance when polished, ground, or hardened. 420 possesses the highest hardness with 50HRC among all steel grades.

This grade contains hardening properties which, however, makes it difficult to weld. Martensitic stainless steels like that of 420 stainless steels are designed for high levels of hardness. Unlike austenitic steels which have proven record in great corrosion resistance to high temperatures, martensitic stainless steels’ corrosion resisting properties can be achieved as the metals undergone hardening, grinding, and polishing.

420 stainless steels are used in a wide variety of industrial applications where good corrosion resistance is needed, examples include:

• Shear blades
• Hand tools
• Cutlery
• Surgical and dental instruments
• Knife blades
• Scissors
  
• Needle valves
• Pump shafts
• Straight edges
• Gauges
• Ball bearings
• Pivots

However, 420 stainless steels are also not usually used in applications involving temperatures that exceed to 800oF (427°C) due to loss of corrosion resistance and quick hardening – which is why 420 is not commonly welded. It is best advised to perform welding right after preheating to 300°F to 400°F along with post weld tempering for 2 hours.

Upon machinability, 420 can create tough chip buildup. They can be easily machined during their annealed state but it will be difficult for them to be machined if their hardness gets greater than 30HRC. If looking for readily machined alternative steel grades, 416 can be first considered which is a free-machining steel grade type.

If ever you are looking for 420 and other stainless steel grades, you may fill out our free quote or contact us to assist you with your material request.