Home / Standards / GB/T 4697-2017 GB/T 4697-2017 Active Hot rolled steel section for mine timbering 矿山巷道支护用热轧型钢 Standard Type GBT ICS 77.140.70 CCS H44 Status 现行 Issue Date 2017-07-12 Implementation 2018-04-01 Responsible Dept 中国钢铁工业协会 Drafting Unit N/A