Home / Standards / GB/T 131-1993 GB/T 131-1993 Abolished Mechanical drawings--Surface roughness symbols and methods of indicating 机械制图 表面粗糙度符号、代号及其注法 Standard Type GBT ICS 01.100.01 CCS J04 Status 废止 Issue Date 1993-11-09 Implementation 1994-07-01 Responsible Dept 国家标准委 Drafting Unit N/A