1.4021, DIN X20Cr13, AISI 420

1.4021, DIN X20Cr13, AISI 420

Designation by Standards

 

Chemical Composition (in weight %)

 

Description
This alloy is a general purpose heat treatable chromium steel which is a popular cutlery grade. Martensitic stainless steel.

Applications
Dental and surgical instruments, cutlery, pump shafts, plastic molds and dies, steel balls, and various hand tools, pump components, shafts, turbine blades, pressing dies for tablets, glass and plastics processing tools.

Physical properties (avarage 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

Coefficient of Linear Thermal Expansion 10^{-6 o}C^-1

 

Modulus of Elasticity [10³ N/mm²]

 

Soft Annealing
Heat to 730-810^oC, air cooling. Structure is ferrite with spherical carbides.

Hardening
Harden from a temperature of 950-1050^oC followed by oil, air quenching.

Tempering
Tempering temperature: 650-750^oC. Transformation structure with ferrite.

Mechanical Properties at Room Temperature

 

0.2 % Proof Stress (N/mm²) at Elevated Temperatures

 

Forging
Hot forming temperature: 1100-850^oC.

Machinability
Similar to machining some of the high carbon steel/" target="_blank" class="keylink">tool steel, this alloy has tough, stringy chip build-up.

Embittlemnt: It must be in mind that the temperature range between 425 and 525^oC must be avoided owing to embritllement at 475^oC.

Corrosion Resistance
420 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 149-204^oC with post weld tempering at temperature for 2 hours. Filler metal should be AWS E/ER420.