| 摘要 |
The present invention relates to a manufacturing method for a welded steel pipe with reduced hot crack and, more specifically, relates to a manufacturing method for a welded steel pipe by applying a welding method to prevent hot cracks caused by an excessive tensile stress on a welded portion by a solidification contraction or a thermal contraction during a welding process. According to an embodiment of the present invention, the manufacturing method for the welded steel pipe comprises: a step of preparing a steel pipe to be welded; a step of preheating a welding portion and a heat-affected zone of the steel pipe during a retention time (tp) defined in a mathematical formula 1 of 0.7(D×t)/(Ts+200) <= tp <= (D×t)/(Ts+200) at a temperature range of 50-300°C; and a step of welding the steel pipe. |
