In order to develop heavy gauge WPHY-80 pipe fitting steel with high strength and low temperature toughness, the experimental research and manufacturing technology have been studied in this paper. The continuous cooling phase transformation behavior of the material under deforming condition was investigated. The microstructure of the steel at different cooling rates was observed by microscope. The temperature gradient rolling process in rough rolling stage was developed, which prompt the deformation penetrated from the surface to the center. It could refine the grain size in the center of the thick plate to enhance uniformity of the microstructure along the thickness direction. By utilizing this process route, the heavy gauge (54mm) WPHY-80 pipe fitting steel with excellent mechanical properties was developed in Shougang steel (SG). The WPHY-80 plates obtained high strength and stable low temperature impact toughness.
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