The dish head is a part of the container, which is connected to the cylinder by welding. (As shown in the figure below) According to different geometric shapes, it can be divided into spherical, elliptical, dish-shaped, spherical cap, cone and flat cover, etc., of which spherical, elliptical, dish-shaped, spherical cap-shaped heads are also collectively referred to as Convex head. In welding, it is divided into butt welding head and socket welding head. Used in various container equipment, such as storage tanks, heat exchangers, towers, reactors, boilers and separation equipment, etc. The materials are carbon steel (A3, 20#, Q235, Q345B, 16Mn, etc.), stainless steel (304, 321, 304L, 316, 316L, etc.), alloy steel (15Mo3 15CrMoV 35CrMoV 45CrMo), aluminum, titanium, copper, nickel and nickel Alloy etc.