Stainless Steel 304

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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.

Stainless-Steel-304
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

Physical Properties

Density: 0.285
lb/inch3

Temperature, °F 212 1600
Coefficient* of Thermal Expansion, in/in°F x 10-6 9.4 -
Thermal Conductivity Btu • ft/ft2 • hr • °F 9.4 10.9


* 70°F to indicated temperature.

Mechanical Properties

Representative Tensile Properties

�@ Minimum Typical
Ultimate Tensile Strength, ksi 75 90
0.2% Yield Strength, ksi 30 35
Elongation, % 40 60

Chemistry

Cr Ni C Mn Si P S Fe
MIN 18.0 8.0 0.04 - - - - -
MAX 20.0 10.5 0.10 2.0 0.75 0.04 0.03 Balance