Calculation of Thermal Stress in Cylindrical Steel during Cooling

Abstract

The paper presented a calculation of thrmal stress in a cylindrical steel induced during cooling by introduction of strain-history into Hara's calculation method.
Calculation was based on elastic-plastic theory and total strain was calculated by non-linear integral equation through a successive integration. Plastic strain was calculated by total strain theory and stress-strain diagram.
A calculation was made for a cylindrical steel bar with 1500mm in diameter quenched in mist from 850°C, and the results are as follows.
(1) Tensile stresses (δ_t, δ_z, ) at surface of bar are the largest, when temperature difference between surface and core was the largest.
(2) Stresses (δ_t, δ_z) at starting point of transformation always show the maximum tensile values.
(3) Reverse of stresses (δ_r, δ_t, δ_z) takes place after completion of transformation of core.
(4) At final stage of cooling, core has tensile stresses (δ_r, δ_t, δ_z) and surface layer has compressive stresses (δ_t, δ_z) of characteristic pattern.