Ferritic SS 444

Specifications

444 steel is dual stabilized with titanium and niobium. It is equivalent to Type 304 in many corrosion environments and has a lower coefficient of expansion and better thermal conductivity. SUS 444 stainless steel has superior chloride stress corrosion cracking resistance to Types 304 and 316. Therefore, among AISI 444 vs 316, type SS 444 is the better option.

[#corrosion-resistance]CORROSION RESISTANCE[#corrosion-resistance]

‍SS 444 chemical composition provides it with excellent corrosion resistance in moderately severe environments of many types that include chlorides and organic acids found in foods and beverages. SS 444 material properties also provide satisfactory resistance to dilute sulfuric acid solutions and to highly concentrated sodium hydroxide.

‍[#fabrication-and-heat-treatment]HEAT TREATMENT[#fabrication-and-heat-treatment]

1. 4521 stainless steel can be normally annealed at 800°C for 90 minutes and followed by air quenching. For 444 fabrication, post-weld annealing might be required. Stress-relieving if required, can be done at about 250°C.

Physical Properties  

FORMABILITY

‍SS Grade 444 provides excellent formability and can be readily deep drawn and spin formed. Stretch forming, however, is limited in application for this material.

‍[#weldability]WELDABILITY[#weldability]

The ferritic class of stainless steel is generally considered to be weldable by common fusion and resistance techniques. Special consideration is required to avoid brittle weld fractures during fabrication by minimizing discontinuities, maintaining low weld heat input, and occasionally warming the part somewhat before forming. When weld filler is needed, AWS E/ER 316L is most often specified.