Home / Standards / GB/T 31309-2020 GB/T 31309-2020 Abolished Calculation of electron vacancy number in cast superalloys 铸造高温合金电子空位数计算方法 Standard Type GBT ICS 77.040.99 CCS H24 Status 废止 Issue Date 2020-06-02 Implementation 2021-01-01 Responsible Dept 中国钢铁工业协会 Drafting Unit N/A