Microstructure and Mechanical Properties of High-silicon K52 Pipeline Steel in Cold Area

In this paper, high-silicon K52 and API X52 were studied comparatively, which were with similar yield strength. The results showed that K52 with high-silicon and low-manganese asked for higher tensile strength, lower yield ratio and higher impact energy than API X52. K52 was successfully producted with more content of Nb, V, Ti and so on, which is with high tensile strength, low yield ratio and high impact energy. The oxide scale of K52 was more thichness because of the high-silic. The thickness of oxide scale could be reduced by the lower tapping temperature during hot rolling. The inclusion of silicon oxide was bad fot the toughness of welding line, which was forming during the welding process.The squeeze amount should be increased to improve the impact energy of welds.