Effect of residual compressive stress field on fatigue crack growth of B780CF steel welded joints

In order to know the effect that residual pressure stress field with different strength to the crack growth rate and life, The standard CT samples of welded joints are prepared through mechanical processing, which coming from the automatic submerged arc welding with different welding line energy and grouping with different residual compressive stress field. Then put forward a three-parameters formula based on the Elber according to the principle of crack closure, which is used to analyze the closure test data from MTS testing machine by the method of fracture mechanics and mathematical statistics. Then get the conclusion, in a certain extent, the welding residual pressure stress field can significantly reduce the crack growth rate, improve the crack propagation life, which plays a key role in crack propagation of welded joint.