1.4864, DIN X12NiCrSi36-16, AISI 330

1.4864, DIN X12NiCrSi36-16, AISI 330

Designation by Standards

 

Chemical Composition (in weight %)

Description
PK20 is an austenitic, nickel-chromium-iron-silicon alloy. It combines excellent resistance to carburization and oxidation at temperatures up to 1200^oC with high strength. Steel is not resistant in sulphur containing gas.

Applications
Extensively used in high temperature environments where resistance to the combine effects of thermal cycling and carburization is necessary. Used in a variety of furnace components as well as in gas turbines, heat exchangers, general heat treating equipment and neutral and cyanide salt pots.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [10³ x N/mm²]: 195, 184(200^oC), 170(400^oC), 157 (600^oC), 143 (800^oC)
Density [g/cm³]: 8.0
Thermal conductivity [W/m.K]: 13.0, 19 (500^oC)
Electric resistivity [Ohm mm²/m]: 1.0
Specific heat capacity[J/g.K]: 0.50

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

Annealing or Quenching
Harden from a temperature of 1050-1100^oC, followed by water or air quenching. Structure is austenite + ferrite.

Mechanical properties at at ambient temperature
Condition: quenched
Hardness: max. 223 HB
0.2 % proof stress: 230 N/mm²
Tensile strength: 550-800 N/mm²
Elongation: 30%

1% Creep Stress in N/mm² vs. Temperature in ^oC

Creep Rupture Stress in N/mm² vs. Temperature in ^oC

Forging
Hot forming temperature: 1150-850^oC.

Machinability
With proper practices this alloy can be satisfactorily machined. Slow speeds, positive feeds, sulphurized lubricants and rigid mounts are generally recommended.

Welding
Can be successfully welded using GAW techniques. Use either 330 or Inco 800 filler materials.

Cold working
Due to its relatively high strength and work hardening rate, 330 is more difficult to cold form than standard 18-8 stainless steels. Expect to use higher forces than normal and note its' elevated springback.