PIERCER PLUG MATERIAL FOR PRODUCING SEAMLESS STEEL TUBE, AND METHOD FOR PRODUCING SAID MATERIAL

摘要

The present invention relates to a piercer plug which is used when using the Mannesmann process to manufacture seamless steel pipe, more particularly relates to a material for piercer plug for manufacturing seamless steel pipe which is excellent in season cracking resistance and machinability and a method of manufacturing the same. The material for piercer plug comprises as components, by mass%, C: 0.08 to 0.3%, Si: 0.1 to 1.0%, Mn: 0.2 to 1.5%, Ni: 0.2 to 2.0%, and, furthermore, one or both of W and Mo in a total of 1.5% to 8%, a balance of Fe and impurities, wherein the amount of diffusible hydrogen which is contained as an impurity is in 2 ppm or less. The material for piercer plug has a hardness between HRC 6 and 10.