Carbon steel tees is also a kind of pipe fittings, there are generally two kinds. The equal diameter three pass has the same diameter at both ends, and the branch pipe is different from the other two diameters. The utility model is called a diameter three pass. The method of expression is as follows: for equal diameter three pass, such as "T3" three, the general rule indicates that the outer diameter is 3 inches and the diameter is three. For a differential three pass, such as "T4 * 4 * 3.5", the same diameter is four inches, the diameter is 3.5 inches, and the diameter is three. 20# A3 Q235A made of 10# 20g 20G 16Mn ASTM A234 ASTM A105 ASTM A403, three, the diameter is in the range of 2.5 - 60 "", "" from 26 - 60 for welding three. Wall thickness 28 - 60mm. The pressure levels are Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS, Sch80, Sch100, Sch120, Sch140, Sch160,, and XXS.