To provide a method for determining propagation stop characteristic of high-speed ductile fracture of a steel pipe, for preventing a large-scale accident by high-speed ductile fracture by performing a characteristic evaluation by the use of a test piece suitable to material evaluation of shearing crack propagation resistance which is important in high-speed ductile fracture.
In this method for determining propagation stop characteristic of high-speed ductile fracture of a steel pipe used in a gas pipeline or the like, an obliquely pre-cracked DWTT test piece in which the crack tip envelope of a steel pipe thickness (plate thickness) directional through crack propagating in the steel pipe axial direction is inclined from the steel pipe thickness direction in a steel pipe circumferential section is used, and when the test absorption energy under the using temperature condition of the steel pipe satisfies DWTTslp(J) represented by the following equation or more, this steel pipe is determined to be capable of stopping propagation of high-speed ductile fracture. DWTTslp=2.3×10-5×D2.3×t-1×P2 ... (A), wherein D is the steel pipe outer diameter (mm), t is the thickness (mm), and P is the using pressure (MPa).
SHIMANUKI HIROSHI
KOSEKI TADASHI
Shiina Akira
Next Patent: MAGNETIC MEASURING DEVICE AND MAGNETIC MEASURING METHOD FOR STATOR CORE