SS 904L Properties

Heat Resistance

Grade 904L stainless steels offer good oxidation resistance. However, the structural stability of this grade collapses at high temperatures, particularly above 400°C.

Heat Treatment

Grade 904L stainless steels can be solution heat-treated at 1090 to 1175°C, following by rapid cooling. Thermal treatment is suitable for hardening these grades.

Welding

Alloy 904L can be readily welded by most standard processes. Pre-heat and post-weld heat treatments for this grade are not required. The corrosion resistance property of 904L stainless steel is impaired in certain environments due to the redistribution of nickel, molybdenum and chromium caused by the solidification of material after welding, although this is less evident in 904L grade. SS 904L electrodes and rods are used for welding grade 904L steels according to AS 1554.6.

Fabrication of Stainless Steel 904L

Machining This grade can be machined using any standard methods, slow speeds and positive feed minimises the alloy’s tendency to work harden and glaze. The cold work hardening rate of 904L Alloy makes it less machinable than 410 and 304 stainless steels. Hot working For Hot working process of 904L a temperature range of 1562–2102°F is recommended .Hot working is followed a solution anneal and quench but 904L stainless steel may be used without subsequent heat treatment if the hot forming is discontinued above 2012°F and the material is quenched directly thereafter. In the event of partial heating or cooling below 2012°F, or if the cooling has been too slow, hot working should always be followed by a solution anneal and quenching. 904L should be solution annealed at 1940–2084°F. Cold working 904L is quite ductile and forms easily. The addition of molybdenum and nitrogen implies more powerful processing equipment may be necessary when compared with the standard 304/304L grades. Hardening This alloy does not respond to heat treatment. It may only be hardened by cold reduction.