Abstract
Thermal fatigue cracking may initiate at a T-junction pipe where high and low temperature fluids flow in from different directions and mix. Thermal stress is caused by a temperature gradient in a structure and by its variation. It is possible to obtain stress distributions if the enough temperature distributions on the pipe inner surface are obtained by experiments. The wall temperature distributions at a T-junction pipe were measured by the thermocouples installed in inner surface of a stainless steel pipe. The thermal stress distributions were calculated using the temperature in the pipe inner surface. The large stress fluctuations were caused by the swaying of the compressive stress region in the circumferential direction. The distribution of the stress fluctuation range was similar to that of the temperature fluctuation range. The large temperature fluctuation with the period of about 10s caused the large stress fluctuation.
