Seamless steel pipe and method for manufacturing seamless steel pipe
The seamless steel pipe with a tailored composition and microstructure addresses the issue of inadequate fatigue crack propagation resistance in high-pressure hydrogen environments, offering enhanced resistance to hydrogen embrittlement while maintaining cost-effectiveness and structural integrity.
WO2026116398A1PCT designated stage Publication Date: 2026-06-04JFE STEEL CORP
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2025-11-26
- Publication Date
- 2026-06-04
Smart Images
Figure JPOXMLDOC01-APPB-M000001 
Figure JPOXMLDOC01-APPB-M000002 
Figure JPOXMLDOC01-APPB-M000003
Abstract
The purpose of the present invention is to provide: a seamless steel pipe having excellent fatigue crack growth resistance under a hydrogen gas environment; and a method for manufacturing same. The seamless steel pipe has a specific component composition and has a steel structure in which the area fraction of bainite is 90% or more in a range from the inner surface of the seamless steel pipe to a 1 / 4 pipe thickness position, the area fraction of bainite grains having a circle equivalent diameter of less than 18 μm is 50% or more with respect to the area fraction of total bainite, the total bainite has grain boundaries having a grain misorientation of 0.5° or more and less than 2.0°, and the average number of the grain boundaries having a grain misorientation of 0.5° or more and less than 2.0° is 10 or more on an arbitrary 100 μm straight line drawn for measurement within the total bainite. The total bainite refers to the total bainite in the steel structure.
Need to check novelty before this filing date? Find Prior Art