Home / Standards / YB 4052-1991 YB 4052-1991 Active 高镍铬无限冷硬离心铸铁轧辊金相检验 Standard Type YB40 ICS N/A CCS N/A Status Active Issue Date 1991-05-03 Implementation 1992-01-01 Centralized Committee 冶金工业部 Issuing Authority 冶金工业部