Carbon steel flanges are tight and reliable. The utility model has two sealing surfaces, and the sealing surface material of the ball valve is widely used in various kinds of plastics, and the sealing property is good, and the sealing can be realized completely. Because carbon steel flanges are wiped during opening and closing, they can be used in medium with suspended solid particles. Model Q41F--16C Q41F--25C A105 American Standard about 0.9% (the standard is 1.05Max with carbon content can decrease to 1.65%Max) to GB 16Mn content in about 1.3% (1.2%~1.6%) on the standard S25C words is relatively low under 0.6%