Thermal and Residual Stresses of Circular Cylinders Suddenly Cooled from Uniformly Heated Condition

Abstract

In the previous papers, we have studied, theoretically and experimentally, the thermal and residual stresses under one and two dimensional stress distribution and followed up the causes of the residual stresses for each cases.In this report, let us deal with the shrinkage stresses of circular cylinders rapidly cooled in water from uniformly heated condition, as an example for the case of three dimensional stress distribution.To avoid the effects of the transformation stresses, we used the low carbon steel and the heating temperature was hold 600°C under the transformation temperature.Three kinds of test cylinders were made, and the diameters were 40, 50 and 60mm respectively; however the length of each ones was constant 150mm.We measured the cooling temperature at the outer surface of the test cylinders and the residual stress distribution by Sachs'method. These results are plated Fig. 2 and 8 respectively.To analyse these experimental results, we calculated the temperature distribution at each moment as shown in Fig. 3, and obtained, by plastic calculation, the maximum plastic deformation, which will occur in some part during cooling. This maximum plastic deformation, components of which are expressed by gr, gt and gz in this paper, becomes the cause of constraint to the residual stresses.The residual stress distribution can be obtained as a special case of thermal stress during the cooling of the test cylinder by using the respective stress-strain relations for the elastic and plastic zone.The theoretical stress distribution is shown in Fig. 6, and the residual stress due to heating and cooling can be calculated theoretically with sufflcient accuracy, not only for one or two dimensional stress distribution but for three dimensional one.