Study on Properties of CC Billet-made P91 Steel Pipe and Analysis of its Engineering Application

Addressing the remaining doubts about the engineering application of the P91 steel pipe as made of the CC billet that are held by users of the domestic boiler industry,the current quality status of the home-made Gr.91 CC billet is analyzed. And the P91 steel pipes as manufactured with the CC billet and by a couple of domestic steel works are studied by means of physical and chemical inspections,and high temperature aging and high temperature creep rupture tests. As a result it is revealed as follows. The domestic melting technology for the Gr.91 CC billet is mature,and the steel proper possesses advantages as high steel cleanness, homogeneous macrostructure, fine columnar crystal morphology and regular central crack distribution. The chemical composition, the mechanical properties and the metallographic characteristics of the CC billet-made P91 steel pipe are all in compliance with applicable standard requirements. Moreover the post-high temperature aging properties of the pipe are stable,and the 600 益 100 000 h extrapolated creep rupture strength is equivalent to that of the steel tube made of the conventional forged billet. Accordingly it is suggested that all the stakeholders dispel their doubts,and promote the engineering application of the CC billet-made P91 steel pipe.