Transient and residual thermal stresses in quenched cylindrical bodies

To predict residual and thermal stresses which occur during water quenching of solid cylindrical rod and ring cross-sectioned steel tubes, a finite el ement technique has been used. The variations of residual stresses on diffe rent surfaces and cross-sections, e.g. in the radial, axial and tangential directions have been examined, and the effect of internal diameter of tubes on residual stress was investigated. The results show that the residual st resses act as a compressive force along the cooling surface and then by mov ing away from the surface begin to decrease and reverse their sign, near th e centre of the cylinder are subjected to tensile stresses. Because of the reversal of the sign of stress, the effective stress goes to a minimum at s ome distance from the frontal surface and this may be vital since lower pla stic deformation may cause cracking failure. As in solid cylinder, in cylin drical tubes also, the frontal and the upper cooling surface has significan t effect on the stress distribution. From the comparison of the residual st ress distributions of solid cylinder and cylindrical tubes and using their individual stress maps it was seen that they vary considerably along differ ent cooling surfaces, especially at the frontal surface. (C) 2000 Elsevier Science Ltd. All rights reserved.