Abstract
The transient thermal stresses of 13 Cr cast steels (SCS5) and structural carbon steels (SM41B) are investigated by round bar specimens of which both ends are fixed and subjected to thermal prestraining cycles to simulate welding process. The multi-thermal prestraining cycles tests are conducted in the case of fixed peak temperature (600°C and 1000°C) and increasing peak temperature (200°C-1000°C) and decreasing peak temperature (1000-200°C), respectively. The experimental results indicate that the effects of transformation on residual stress of SCS5 steels are remarkable, and the effects of multi-thermal prestraining cycles on residual stress are negligible in both SCS5 and SM41B. These results are compared with several weldments. For example, three dimensional residual stress distributions of 13 Cr cast steel weldment prepared with homogeneous weld metal are measured by Ueda-Fukuda's method. It is observed that the maximum compressive residual stress is -210 MPa at the bottom of the final weld pass and the maximum tensile residual stress is 310 MPa at the region out of the HAZ. It is shown that the both-ends fixed bar test subjected to multi-thermal cycles of incremental steps is available to simply estimate the residual stress characteristics.
