FERRITIC SS 441
Ferritic SS 441 is one of the superior grades used in the industry. With its exceptional chemical composition, having 18% chromium content and dual addition of titanium and niobium, it gives an excellent resistance to corrosion, high ductility and exceptional welding properties.
The composition gives the alloy a very fine grain structure, the grains equiaxed in all directions imparts commendable properties to the alloy. The intergranular corrosion of the alloy is low whilst the chromium content elevates the crevice resistance.
The alpha iron in the grain structure, like other Ferritic grades, imparts its magnetic properties.
The flat rolled metal of the grade retains its magnetic properties under all conditions. Normally, Ferritic steels do not give high temperature strength but with an additional columbium stabilisation in the alloy, there is further enhancing of the high temperature strength, creep-rupture strength and corrosion resistance properties. With appropriate heat treatment like annealing and columbium (niobium) stabilisation, the metal can give exceptional performance under load at elevated temperatures. Hence, properties like deep drawing, good weldability, and good brightness can be retained.
The dual addition of titanium and niobium enhances the welding property by restricting the formation of martensite at the heat affected zone, making the alloy ferritic at all conditions. Moreover, the carbon content (0.03%) reinforces the ductility of the alloy under all conditions. The grade has low work hardening rate, similar to other ferritic alloys, and hence the grade can be suitably deep drawn, cold formed, work stretched and machined. The grade is typically used in the gas exhaust systems due to its capability of resisting oxidation up to 900- 950°C. The chloride resistance of the grade is low, and crevice corrosion is possible depending upon chloride concentrations. With an efficient metal design, appropriate heat treatment, regular maintenance, the alloy can have commendable performance under various environments.
|Thermal Conductivity @ 70°F
|25 W/ mK
|460 J/ kgK
|Young’s Modulus x 10ᵌ
|Modulus of elasticity
Catalytic converter shells, Clamps, Kitchen Catering and appliance, work surfaces, shelving, Automotive exhaust system components, Exhaust system parts, Heat exchangers, Wall panels and claddings, Elevators panels and doors, Tubes.
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