Grade 904L stainless steel is a non-stabilized austenitic stainless steel with low carbon content. This high alloy stainless
steel is added with copper to improve its resistance to strong reducing acids, such as sulphuric acid. The steel is also resistant to stress corrosion cracking and crevice corrosion. Grade 904L is non-magnetic, and offers excellent formability, toughness and weldability.Grade 904L contains high amounts of expensive ingredients, such as molybdenum and nickel. Today, most of the applications that employ grade 904L are replaced by low-cost duplex stainless steel 2205.
The socket welding cap is a component of a container and is connected to the cylinder body by welding. Depending on the different geometric shapes, it can be classified into several types such as spherical, elliptical, disc-shaped, spherical cap-shaped, conical shell, and flat cover. Among them, spherical, elliptical, disc-shaped, and spherical cap-shaped heads are collectively referred to as convex heads. In terms of welding, they can be divided into butt-weld heads and socket-weld heads. They are used in various container equipment such as storage tanks, heat exchangers, towers, reaction vessels, boilers, and separation equipment, etc. The materials include carbon steel, stainless steel, alloy steel, aluminum, titanium, copper, nickel, and nickel alloys, etc. The pipe cap is the end cover of a pressure vessel and is a main pressure-bearing component of the pressure vessel. Its function is to seal. One is to form the upper and lower bottoms of the cylindrical pressure vessel, and the other is when the pipeline reaches the end and is not intended to extend further, then a head is used to seal the pipe by welding. Products similar to the head in function include blind plates and pipe caps, but these two products can be disassembled. However, after the head is welded, it cannot be disassembled again. The corresponding pipe fittings include products such as pressure vessels, pipes, flanges, elbows, tris, and quadris.