Because the single measurement time of the ultrasonic hardness tester is about 6 second per time, the efficiency is improved by 17 times compared with the desktop Rockwell hardness tester. And the indentation diameter after the ultrasonic hardness tester is 0.026mm, and the indentation diameter after the Rockwell hardness tester is 0.484mm (see Figure two for the indentation). The ultrasonic hardness tester does not affect the subsequent assembly and use.