Calculation of crack extension rate of high-strength pipeline steel

Crack extension rate is one of the important parameters to predict arrest toughness. Based on the calculation models of crack extension rate worked out through full-size explosion tests in the world, that is, BTCM model, HLP model and Sumitomo Model, the crack extension rate of X80 pipeline steel has been calculated, and the influences of diameter, wall thickness and strength on crack extension rate have been studied. The results show that the crack extension rates calculated by HLP model and Sumitomo model are consistent with the measured data through full-size explosion of high-strength steel, while the predicted data of BTCM model deviated greatly from such measured data. The calculation results with BTCM model, HLP model and Sumitomo model indicate that along with the increase of wall thickness and strength, the maximum crack extension rate decreases, thereby helping to stop the cracking of pipeline; when pipeline diameter increases, the maximum crack extension rate increases, which accordingly demands higher arrest toughness.