Designation by Standards
| Steel No. | DIN | EN | AISI | JIS | ГОСТ |
| 1.2083 | X42Cr13 | X40Cr14 | 420 mod. | SUS420J2 | / |
Chemical Composition (in weight %)
| C | Si | Mn | Cr | P | S | Ni | Mo | Others |
| 0.39 | max. 1.0 | max. 1.0 | 13.50 | - | - | - | - | - |
Description
Tool steel with high dissolved Cr content in the steel matrix. Good corrosion resistant in the hardened condition, good polishability, good machinability, low distorsion, high wear resisatnce and high surface finish. This grade can be produced on request by the process ESR and quenched and tempered condition.
Applications
Moulds for corrosive plastic materials such as PVC, recycled polymers etc., moulds for chemically aggressive plastics and plastics containing abrasive fillers, mould inserts, dies and gauges for PVC extrusions, screws and barrels for extruders, moulds for automotive, food, medical and optical industry such as spectacles, compact discs, lenses.
Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 220
Density [g/cm3]: 7.80
Specific heat capacity[J/g.K]: 0.46
Coefficient of Linear Thermal Expansion 10-6 oC-1
| 20-100oC | 20-200oC | 20-300oC | 20-400oC |
| 10.5 | 10.9 | 11.3 | 11.6 |
Thermal conductivity [W/m.K]
| 20oC | 200oC | 300oC |
| 22.0 | 24.0 | 26.0 |
Soft Annealing
Heat to 760-800oC, cool slowly in furnace. Max. hardness 241 HB.
Stress-relieving
After rough machining the tool should be heated through to 650°C, holding time 2 hours. Cool slowly to 500°C, then freely in air.
Hardening
Preheating temperature: 600–850°C. Harden from a temperature of 1000-1050oC followed by oil, vacuum, pressure gas (N2), air or hot bath ar 500-550 C quenching. Protect the part against decarburization and oxidation during hardening. Soaking time: 1020°C, 30 minutes, 1050°C, 30 minutes. Soaking time = time at hardening temperature after the tool is fully heated through.
Tempering
Tempering temperature: 250-570oC.
Forging
Hot forming temperature: 1050-850oC.
Machinability
Similar to machining some of the high carbon tool steel, this alloy has tough, stringy chip build-up.
Corrosion Resistance
AISI 420 mod. is resistant to the atmosphere, fresh water, dilute acids and alkalis and fruit and vegetable juices.
Welding
Not commonly welded due to its air hardening characteristics. Welding may be performed after preheating to 149-204oC with post weld tempering at temperature for 2 hours. Filler metal should be AWS E/ER420.
Note: The hot forming temperature stated should not be exceeed, as harmful grain coarsening and simultaneous formation of a carbide network along the grain boundaries will otherwise occur. This results in poor developmnet of hardness and a decline in toughness and elasticity in hardened condition.
Remark
All technical information is for reference only.