The steel fully welded ball valve is a very common valve, its main feature is that because the ball and the valve body are welded into one piece, the valve is not easy to produce leakage during use. It is mainly composed of valve body, ball, stem, seat, gasket and so on. The stem is connected to the valve handwheel through the ball, and the handwheel is rotated to turn the ball to open and close the valve. Production materials vary according to the use of different environments, media, etc., mainly carbon steel, stainless steel, alloy steel, cast steel, etc.