... these aspects such as smelting technology and facilities, machining process and facilities and heat treatment process and facilities. We can produce the ... perfectly they are general rods series and quick gods series with different length such as T38-3.66m general ... T51,ST58 thread, the diameter of drilling pipe 46mm, 56mm, 65mm, 76mm, 87mm, length 1220mm, 1525mm, 1830mm, 2280mm, 3050mm, 3660mm.