Method and system for evaluating ultrasonic detection capability of stainless steel small-diameter tube welding seam

The invention provides a method and a system for evaluating the ultrasonic detection capability of a stainless steel small-diameter pipe welding seam. The method comprises the following steps: establishing a multi-mode ultrasonic defect response model; relevant parameters of the stainless steel material are obtained, wherein the relevant parameters specifically comprise stainless steel material parameters, a sound wave propagation path, directivity, a diffusion attenuation coefficient, material attenuation, a reflection and transmission coefficient and a defect scattering coefficient; calculating ultrasonic defect response space distribution in different modes, introducing a defect response model into an array signal, calculating a defect response amplitude superposition result of all positions, and forming a space distribution diagram of ultrasonic defect response; and calculating evaluation parameters. According to the method, accurate calculation of defect response at any position of a detection area in th