公开(公告)号：US20240141451A1

公开(公告)日：2024-05-02

申请号：US18547624

申请日：2022-03-24

Applicant: NIPPON STEEL CORPORATION

Inventor： Kenzo TASHIMA ,  Kensuke NAGAI ,  Tatsuo YOKOI ,  Mitsuhiro HAMAISHI ,  Takashi TSUSUE

IPC: C21D9/08 ,  B21C37/08 ,  C21D8/10 ,  C21D9/50 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14

CPC classification number: C21D9/08 ,  B21C37/08 ,  C21D8/105 ,  C21D9/50 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14 ,  C21D2201/00 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/009

Abstract: A hot-stretch-reduced electric resistance welded pipe has a base metal portion and a weld portion, the base metal portion has a predetermined chemical composition, a Ti/N value obtained by dividing Ti content by N content is 3.0 or more, in a microstructure of the weld portion, the average grain diameter is 10.0 μm or less, the area ratio of ferrite is 20% or more, and the remaining structure includes at least one or more of pearlite and bainite/martensite, and in a texture of the weld portion, the accumulation intensity of a {001} plane is 6.0 or less, and a critical cooling rate Vc90 of the base metal portion is 5° C./s to 90° C./s.