Home / Standards / GB/T 7731.4-2021 GB/T 7731.4-2021 Active Ferrotungsten—Determination of phosphorus content—Phosphorus molybdenum blue spectrophotometric method 钨铁 磷含量的测定 磷钼蓝分光光度法 Standard Type GBT ICS 77.100 CCS H11 Status 现行 Issue Date 2021-08-20 Implementation 2022-03-01 Responsible Dept 中国钢铁工业协会 Drafting Unit N/A