Home / Standards / GB/T 4697-2008 GB/T 4697-2008 Abolished Hot-rolled U-type steel for mine timbering 矿山巷道支护用热轧U型钢 Standard Type GBT ICS 77.140.70 CCS H44 Status 废止 Issue Date 2008-08-05 Implementation 2009-04-01 Responsible Dept 中国钢铁工业协会 Drafting Unit N/A