420 Stainless Steel - 1.4034 - X46Cr13 - 51420 - ~SUS 420J1

420 stainless steel has, in its annealed condition, good ductility and can, when hardened, reach a hardness of min. 469 BHN (50 HRC). As a martensitic stainless steel 420 is optimized for its high hardness, while other properties are compromised to some degree. 420 loses ductility at sub-zero temperatures and is in comparison to austenitic steels less corrosion resistant, has poor weldability and loses strength when over-tempered at elevated temperatures.

Applications

Applications for this tool steel include: dental instruments, scissors, gauges, needle valves, ball check valves, pivots and magnets.

Corrosion resistance

420 stainless steel has a good resistance to water and steam, and a moderately resistance to corrosive environments free of chlorides. 420 is not resistant to intergranular corrosion after being welded or in its annealed condition. Where corrosion resistance is an issue, care should be taken not to over temper the material or use it in its annealed condition, but to use it in the hardened condition with a high finished, smooth surface.

Heat resistance

420 should be used at moderately elevated temperatures, it is not recommended to use it for high temperatures above 800°F (427°C) as it reduces the corrosion resistance and mechanical properties.

Annealing

To anneal 420 stainless hold the material at a temperature range of 1382-1562°F (750-850°C) and cool slowly in the furnace or in air.

Stress relieving

Heat the work piece to a temperature of 300-800°F (149-427°C) and hold for 1-3 hours, then cool in air or quench in oil or water.

Hardening

Heat the steel uniformly to 1922°F (1050°C) and follow this up with a rapid cooling in air or oil.

Tempering

To reach a variety of hardness values and mechanical properties heat the work piece to 300-400°F (149-204°C) and cool in air. For optimal corrosion resistance and mechanical properties, the temperature range of 797-1112°F (425-600C) should be avoided.

For our tempering diagram, please click here.

Hot working

Slowly and uniformly heat to a temperature of 1400°F (760°C) and then further to 2000-2200°F (1093-1204°C). To avoid cracking cool slowly in the furnace. Do not let the temperature drop below 1600°F (871°C) and reheat as necessary.

Cold working

Excessive forming can result in cracking, therefore 420 tolerates only minor cold work.

Quenched 420 may be poorly magnetizable. With increased cold working, the magnetizability increases.

Machinability

420 stainless steel machines similar to some high carbon steels and creates tough stringy chips.