Large-diameter thick-walled pipes are made from round steel by piercing to form rough pipes, which are then hot rolled, cold rolled, or cold drawn. They hold a significant position in the Chinese steel pipe industry. According to incomplete statistics, there are approximately 240 large-diameter thick-walled pipe production enterprises in China, with over 250 seamless steel pipe units, and an annual production capacity of over 4.5 million tons. In terms of diameter, pipes with φ76 or less account for 35%, and those with φ159-650 account for 25%. By type, general-purpose pipes total 1.9 million tons, accounting for 54%; oil pipes total 760,000 tons, accounting for 5.7%; hydraulic props and precision pipes total 150,000 tons, accounting for 4.3%; stainless steel pipes, bearing pipes, and automotive pipes together total 50,000 tons, accounting for 1.4%.