| 摘要 |
An electric resistance welded steel pipe manufacturing method capable of improving hydrogen induced cracking resistance and low temperature toughness of a welding part of the electric resistance welded steel pipe by properly controlling an electric resistance welding process and a welding part heat treatment process respectively when manufacturing an electric resistance welded steel pipe by high frequency electric resistance welding is provided. A method of manufacturing an electric resistance welded steel pipe comprises: a step of maintaining a convergence angle of both ends of a steel material bolded during an electric resistance welding process to a gap of 4 to 6 degrees of an angle based on a welding point; a high frequency electric resistance welding step of calculating a relationship among high frequency output(P.I), welding speed(W.S), upset amount(U.F) and steel material thickness(t) by an expression, 23<P.I/W.S + t/U.F<27, wherein P.I represents a high frequency output of 370 to 430 kW, W.S represents a welding speed of 15 to 19 m/min, t represents a steel material thickness of 11.6 mm, and U.F represents an upset amount of 4.3 to 6.6 mm, and controlling a value calculated by the expression to a range of 23 to 27; a welding part heat treatment step of controlling the maximum heating temperature of an outer surface of the steel pipe to a temperature range of 950 to 970 deg.C when heat-treating an electric resistance welding part; and an air cooling step.
|
