Accelerated Test Study of Residual Life Mathematical Model for the Friction Welded Joints in Boiler Snake Pipe

Based on reliability theory, the specification of accelerate life test for friction welded joints in boiler snake pipe was worked out. The correctness of the specification and the concordance of the failure mechanism on the different combined stress levels were verified by hightemperature internal pressure burst duration test for a large number new friction welded joints of 15CrMo steel. The mathematical model, which was used to calculate residual life with reliability for the friction welded joints of 12Cr1MoV steel having worked 132 000 hours, was set up. Through calculation of the test data, the following conclusions were drawn:the friction welded joints is very reliable in the design life; the quality of the friction welding procedure is stable. The test method and mathematical model related in thepaper also have practical value to forecast the residual life for high-temperature pressure-containing and to de-termine the refresh time for extended service pipe and welded joint.