... alloy, electroplating layer and carburizing, nit riding. 1) The hardness tester can be used to test the surface Rockwell hardness of ... , nit riding, cyanide layer; It is an indispensable hardness measuring instrument in machinery, metallurgy and metrology department.2)Main technical specifications ... testing bench: a standard Rockwell hardness block: five Rockwell Hardness Tester HR-150A