Features of 904L alloy steel

904L is a highly alloyed austenitic stainless steel with very low carbon content. The steel is designed for harsh corrosive environments. The alloy was originally developed for corrosion resistance in dilute sulfuric acid. This feature has been proved to be very successful after years of practical application. Now 904L has been standardized in many countries and has been approved for use in manufacturing pressure vessels.

Like other commonly used CrNi austenitic steels, 904L alloy has good resistance to pitting corrosion and crevice corrosion, high resistance to stress corrosion cracking, good resistance to intergranular corrosion, good workability and workability. Weldability. During hot forging, the maximum heating temperature can reach 1180 degrees Celsius, and the minimum stop forging temperature is not less than 900 degrees Celsius. The hot forming of this steel can be carried out at 1000-1150 degrees Celsius.

The heat treatment process of the steel is 1100--1150 degrees Celsius, and it is quickly cooled after heating. Although this steel can be welded by a general welding process, the most appropriate welding method is manual arc welding and argon tungsten arc welding. When manual arc welding is used to weld plates of no more than 6 mm, the electrode diameter is no more than 2.5 mm; when the plate thickness is greater than 6 mm, the electrode diameter is less than 3.2 mm.

When heat treatment is required after welding, it can be heated at 1075-1125 degrees Celsius and then quickly cooled for treatment. When using tungsten argon arc welding, the filler metal can be the same material electrode, and the weld must be pickled and passivated after welding.