Study on Laws of Radial Strength Distribution of Heavy-wall Weld Pipe

The laws of radial distributions of strength and Bauschinger effect of the heavy-wall weld pipe are analyzed by means of conducting various mechanical tests with round bar specimens processed with samples cut from inner and outer surfaces and middle-wall section of the pipe.Results from the longitudinal testing with round bar specimens shows that the outer surface specimen has the maximum yield strength，the inner surface specimen has the minimum，and the middle-wall section specimen has the yield strength a little bit higher than that of the inner surface one.As for the transversal testing with round bar specimens，the results indicate that specimens cut from different locations of the pipe have almost the same Bauschinger effects.To ensure the consistency and scientificalness of the test data，it is suggested that it be expressively specified in the applicable specification that the round bar test specimens of the heavy-wall weld pipe shall be cut from the middle-wall location.