发明名称 |
WELDED STEEL PIPE WITH EXCELLENT WELDING HEAT-AFFECTED ZONE TOUGHNESS, AND PROCESS FOR PRODUCING SAME |
摘要 |
The purpose of the present invention is to supply a welded steel pipe having excellent welding heat-affected zone toughness, while attaining excellent productivity and without sacrificing the quality of the inner part of the weld. The welded steel pipe having excellent welding heat-affected zone toughness has two butt-welded portions respectively for the inner and outer surfaces, the butt-welded portions having been formed in such a manner that either the inner or the outer surface is welded earlier than the other. The welded steel pipe is characterized in that the welding heat-affected zones have a metallographic structure which has an island martensite (MA) content of 4% or lower in terms of areal proportion and has an average prior austenite grain diameter of 400 µm or smaller, and that the following and others are taken into account: the average prior austenite grain diameters in the welding heat-affected zones formed by the preceding welding and the succeeding welding; the width of each of the weld beads formed by the preceding welding and the succeeding welding, the width being measured at the position 5 mm apart from the bead toe; and the inclination angles of the melt lines of the weld beads formed by the preceding welding and the succeeding welding. |
申请公布号 |
WO2013051249(A1) |
申请公布日期 |
2013.04.11 |
申请号 |
WO2012JP06332 |
申请日期 |
2012.10.03 |
申请人 |
JFE STEEL CORPORATION |
发明人 |
TANIZAWA, AKIHIKO;OTA, YOSHIAKI;UCHITOMI, NORIAKI;OKATSU, MITSUHIRO;NISHIMURA, KIMIHIRO |
分类号 |
B23K9/025;B21C37/08;B23K9/18;B23K9/23;B23K101/06;B23K103/04;C22C38/00;C22C38/58 |
主分类号 |
B23K9/025 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|