In current one-side way of ultrasonic wave method,considering the not cross seam plane test wave velocity as diffraction wave velocity was not strict in theory,and taking all the cracks as vertical cracks was not fit with all conditions.The inclined cracks were also usual.These problems may lead to less accuracy in one-side way of ultrasonic wave method,reducing the quality of test.This article brought up two new test methods such as projection point method and opposite phase method,which could avoid these ...