Prediction and Experimental Verification for Residual Life of F12 Main Steam Pipe with Operation Time of 150 000 h

Experimental study were carried out on creep-rupture strength and high-temperature creep crack initiation and propagation rate (CCGR) for sampling bend of main steam pipe with an accumulated operation time of 150 000 hours. The Larson-Miller equation of original material was determined based on statistical data of high temperature creep-rupture strength of F12 steel. The residual life and an equivalent operating stress of sampling blend were estimated by Larson-Miller equation and creep-rupture strength datas of the sampling blending, and then a high-temperature creep crack initiation and propagation life evaluation method was used to compute the high-temperature creep crak initiation and propagation life of the sampling blend under equivalent stress condition, meanwhile, the residual life was evaluated. At last, the prediction results were verified by microstructure of the sampling blend. The results show that the main steam pipe might had a residual life of 73 515 hours with an equivalent operating stress of 103.97 MPa based on Larson-Miller method, while using creep crack initiation and propagation life evaluation method, the residual life was 153 354 hours. The main steam pipe could operate normally for nearly ten years in safety. The prediction results was agreement with the experimental results.