| Title |
Development of Χ70 HSLA Steel Strip for Arctic Linepipe Application |
| Authors |
김태웅(Tai Ung Kim); 김재은(Jae Eun Kim); 오세익(Se Ik Oh); 김영길(Young Gil Kim) |
| Abstract |
In order to develop an arctic line-pipe of X70 type HSLA steel strip with high toughness and good weldability, additions of several micro-alloying elements and applications of different post-rolling treatments were attempted. On a basic composition of Fe-0.05C-1.0Mn-0.3Si, several micro alloying elements such as Nb, V, Mo and Ni were added. The applied post-rolling treatments were water-spray cooling followed by either furnace cooling or air cooling to room temperature after the final controlled rolling at 800℃. It was found that the steel composition of Fe-0.05C-1.0Mn-0.35Si-0.03Nb-0.05V-0.1 Ni exhibited optimum combination of high strength (Y.S. 75 ksi) and excellent impact toughness 250 joules at -20℃) after the water-spraying to 600℃ followed by a furnace cooling to room temperature. The applied post-rolling treatment was the condition simulating hot strip production. This paper highlights the effects of the micro-alloying elements and the post-rolling treatments on structure and mechanical properties in a low Carbon-Manganese steel. |