Stainless Steel 304
|Dual certified 304/304H is used as a material of construction up to 1500°F. Slight scaling begins at about 1200°F. This is the 0.04% minimum carbon version of type 304 stainless. It has general corrosion resistance similar to the low carbon 304/304L. However, it is subject to carbide precipitation in the heat affected zone (HAZ) of welds. Weldments may be sensitive to HAZ intergranular corrosion in oxidizing acid environments, and to polythionic acid stress corrosion cracking. The carbide precipitation is not harmful to high temperature mechanical properties.
304/304H is welded using the 22Cr 11Ni filler wire (ER308), or covered electrodes (E308). Post-weld heat treatment is not necessary for most high temperature service.
|Machinability of Stainless 422 Comparable to 18-8 but easier to machine Help avoid galling with sharply ground tools Maintain consistent speed and feed Turning tools: 8-14° side rake Drilling: 140° point Threading: grind tools with 10-15° back rake Cobalt high-speed tools: turn at 90-120 sfpm, drill at 40-75 sfpm, mill at 70-120 sfpm, ream at 20-60 sfpm, roughing and finishing at 200-400 sfpm Workability of Stainless 422 Initial forging and rolling at 2100° to 2150°F (1149° to 1177°C) 1700°F (927°C) minimum to hot work
|Coefficient* of Thermal Expansion, in/in°F x 10-6
|Thermal Conductivity Btu • ft/ft2 • hr • °F
* 70°F to indicated temperature.
Representative Tensile Properties
|Ultimate Tensile Strength, ksi
|0.2% Yield Strength, ksi