U.D.C.: 620.178.152.42 June 1980 Conventional Rockwell hardness tests EURONORM Rockwell scales HRN and HRT 109-80 Rockwell scales HRBm and HR 30 Tm for thin products SUMMARY 1 SCOPE A 1.1 Conventional test HRBm 2 PRINCIPLE OF THE TEST A 1.2l test HR 30 Tm 3 FIELD OF APPLICATION A 2 FIELD OF APPLICATION A 2.1 Conventional test HRBm 4 SYMBOLS — DEFINITION AND EXPRESSION OF HARDNESS A 2.2l test HR 30 Tm 4.1 Symbols A 3 SYMBOLS — DEFINITION OF 4.2 Definition and expression of hardness HARDNESS 5 ROCKWELL HARDNESS TESTS HRN A 3.1 Symbols AND HRT A 3.2 Definitions of hardness 5.1 Testing machine A 4 CONVENTIONAL TEST HRBm 5.2 Test piece A 4.1 Testing machine 5.3t method A 4.2 Test piece 5.4 Expression of results A 4.3 Test method 5.5 Limitation of the thickness of the layer tested A 4.4 Expression of results 5.6 Corrections to be added to hardness readings A 5 CONVENTIONAL TEST HR 30 Tm for hardness measurements on cylindrical test pieces A 5.1 Testing machine COMMENTS A 5.2 Test piece Annex: Conventional hardness tests HRBm A 5.3 Test method and HR 30 Tm for thin products A 5.4 Expression of results A 1 PRINCIPLE OF THE TEST COMMENTS 1 SCOPE This EURONORM describes the Rockwell hardness tests N The conventional Rockwell hardness tests HRBm and (cone) and Τ (ball) and specifies the procedures for their HR 30 Tm for thin products are defined in the Annex particular application. hereto. 2 PRINCIPLE OF THE TEST 2.1 2.