Manufacture and Research on Performance and Organizations of New Type Carburized Bainitic Hollow Steel

A manufacturing process of new type carburized bainitic hollow steel by "hot-penetrating and hot-rolling" method is described in this paper. A good surface quality and hot working performance can be achieved by using hot-penetrating and hot-rolling method fabricated new type bainitic hollow steel. The mechanical properties of new type carburized bainitic hollow steel can satisfy the properties of Cr-Ni type carbonized steel requirements, so the hollow steel can be used as drill steel material. The carburized test of new type bainitic hollow steel showed that the new steel is organized by the bainitic, ferrite and austenite; the layer of cementite is organized by the high carbon martensite and austenite. The drill rod with the new type carburized bainitic hollow steel is with good carburization properties. After carburizing air (wind) cold, the surface hardness of the dill rod will satisfy HRC> 5 similar to 7, with good air cooling harden ability and harden ability, so the new type carburized bainitic hollow steelis good at practical application.