446 Stainless Steel

Stainless steels are known as high-alloy steels. They have excellent corrosion resistance in comparison with other steels as they contain more chromium.
Based on their crystalline structure, stainless steels are divided into three groups, namely, martensitic, austenitic and ferritic steels. A combination of martensitic and ferritic steels forms a fourth group known as precipitation-hardened steels.
The grade 446 stainless steel is a ferritic, non-heat treatable stainless steel that provides good resistance to high temperature oxidation and corrosion. The following datasheet provides more details of grade 446 stainless steel.

Other Designations

Equivalent materials to grade 446 stainless steel are:
AISI 446
ASTM A176
ASTM A268
ASTM A276
ASTM A314
ASTM A473
ASTM A511
ASTM A815
DIN 1.4762
QQ S763
QQ S766
ASME SA268
ASTM A580
FED QQ-S-763
FED QQ-S-766
MIL SPEC MIL-S-862
SAE J405 (51446)

Fabrication and Heat Treatment

Machinability

Machinability of the grade 446 stainless steel is possible at slow speeds with positive feeds, rigid mounts and sharp tooling surfaces.

Welding

The grade 446 stainless steel can be easily welded using most of the traditional methods except oxyacetylene welding. Type 308 welding material can be used if required, but it will not exhibit scaling resistance equal to the base metal. Differences in coefficient of thermal expansion of base and weld metal has to be taken into consideration.

Forging

Forging can be started at 1149°C (2100°F) and completed at 871°C (1600°F). The last 10% of forging has to be performed below 871°C (1600°F) to gain grain refinement and room temperature embrittlement.

Hot Working

The hot working of grade 446 stainless steel is performed in between the ranges 1093- 1177°C (2000-2150° F). The last 10% of hot working has to be performed below 871°C (1600°F) to gain grain refinement

Cold Working

The grade 446 stainless steel is more difficult to cold work than other stainless steels due to the high level of chromium content.

Annealing

Annealing of the grade 446 stainless steel has to be soaked at 816°C (1500°F) and then water quenched. The temperature should not exceed 900°C (1650°F) at any time and slow cooling below 649°C (1200°F) can cause loss of ductility.

Applications

The grade 446 stainless steel can be used in the following products:
X-ray tube bases
Boiler baffles
Oil burner components
Annealing boxes
Industrial mufflers
Kiln linings
Glass molds
Furnace parts