PHR Series Superficial Rockwell Hardness Tester The PHR portable superficial Rockwell hardness testers are a variety of the Rockwell hardness testers. They have smaller test forces and thus smaller indentation, used to test the hardness of thin and small workpiceces such as thin metal sheets, tubings, thin shafts, small balls, case hardened materials and other metal parts which require indentation as small as possible. Test range covers low-hardness materials like aluminum, lead, tin; mid-hardness materials like aluminum alloys, copper, copper alloys, stainless steel, cold rolled sheets, tinplate; and high-hardness materials like thin and hard steel strips, carburized and nitrided steel. There is a special Model PHR-1ST superficial Rockwell hardness tester for tubing. It is designed with a round anvil to test the hardness of slim and thin tubes of soft metallic materials. The test result reads in 15 scales, N, T, W, X and Y. The accuracy meets the requirements of GB/T230, ISO6508, ASTM E18. The measurement result can be converted into HRB, HRC, HB, HV or tenstile strength value.