Home / Standards / GB/T 1149.9-2008 GB/T 1149.9-2008 Active Internal combustion engines - Piston rings - Part 9: Keystone rings made of cast iron 内燃机 活塞环 第9部分：梯形铸铁环 Standard Type GBT ICS 27.020 CCS J92 Status 现行 Issue Date 2008-08-11 Implementation 2009-02-01 Responsible Dept 中国机械工业联合会 Drafting Unit N/A