การศึกษาพฤติกรรมความแข็งเครียดจากการเปลี่ยนรูปของเหล็กแผ่นรีดร้อน SAPH440

Abstract

The objective of this project is to study behavior of strain hardening after forming and the microstructure is changing for L-shaped, U-shaped, flange U-shaped bending of material, that metal is SAPH440 hot rolling steel sheet and the method of workpieces forming stimulation is finite-element method.  It used to compare to the actual forming.  The thicknesses of studied material are 1.6, 2.0, 2.3, 2.6 and 3.0 mm.  The punch radiuses of using mold are 3, 4, 5, 6 and 7, and the radiuses of using die are 5, 6, 7, 8 and 9.  The all test results of 3 patterns for changing, that it is occurred before and after forming, is to study factors that influence to workpieces forming, the variable value of mold radius is taken to compare to the strain hardening of partial area that form is changed of workpieces thickness and changed form of workpieces. In summary angle bending has more stain hardening of workpieces. It mean this area has hardness more than. And the area have a lot of stain hardening is tensile , the middle point has down stain hardening and boundary that compressive have down stain hardening boundary little tensile.