| 摘要 |
PROBLEM TO BE SOLVED: To provide a method which is suitable for estimating a pipe axial-direction tensile characteristic of a steel pipe based on a steel plate being a base stock, and accurately estimates the tensile characteristic of the steel plate after subjected to bending working, in a direction orthogonal to the bending working direction based on a tensile characteristic of the steel plate.SOLUTION: The method of estimating a tensile characteristic of a steel plate after subjected to bending working, in a direction orthogonal to a working is provided. In the method, a stress-strain relationship obtained from a tensile strength test piece which is collected from the steel plate after subjected to the bending working, in the direction orthogonal to the working direction is approximated as a Swift equation: &sgr;=C(&egr;+δ)^n. True stress when C: true strain and being a coefficient in the equation is 1, n:work-hardening coefficient, and δ: a change of a correction term before and after the bending working are represented as a function of the residual strain by machining from the plurality of Swift equations :&sgr;=C(&egr;+δ)^n which are obtained at each bending working in which a residual strain amount by machining is changed, and the tensile characteristic in the direction orthogonal to the direction of the working direction after the bending working by an arbitrary working strain amount is estimated from the tensile characteristic of the steel plate. |
