How to test the ceRTificates of PT, rt, MT and UT, which is more useful and valuable? How are they graded? Is it easy to find a job after being admitted?

These four items are divided into three levels, and the third level is the highest. PT is used to detect open circuit defects on the surface of non-porous materials; RT is a perspective detection, which is limited by thickness, and its sensitivity is related to thickness and other factors. MT is used to detect defects on and near the surface of ferromagnetic workpiece; UT is ultrasonic testing. They are all four of the five routine tests, and different detection methods are used in different environments.