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.
Equivalent materials to grade 446 stainless steel are:
MIL SPEC MIL-S-862
SAE J405 (51446)
Fabrication and Heat Treatment
Machinability of the grade 446 stainless steel is possible at slow speeds with positive feeds, rigid mounts and sharp tooling surfaces.
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 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.
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
The grade 446 stainless steel is more difficult to cold work than other stainless steels due to the high level of chromium content.
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.
The grade 446 stainless steel can be used in the following products:
X-ray tube bases
Oil burner components