1970AS 1815.3:2007 Metallic materials - Rockwell hardness test - Calibration of reference blocks (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-3:2005, MOD)
2002AS 1815.3:2002 Metallic materials-Rockwell hardness test Method 3:Calibration of reference blocks (scales A,B,C,D,E,F,G,H,K,N,T)