Abstract: From late twentith century to early twenty-first century, along with further exploitation and uitlization of natural gas and petroleum, new development of domestic piping construction is foreseen, which means a big potential market for large-sized straight weld pipes. To meet the increasing demand of production of line pipes, producers of such products which have enough capability should aim at the said potential market to develop home-made steel plates for pipeline purpose, and promote piping construction of the country.