ICS 25.160.10 J 33 GB 中华人民共和国国家标准 GB/T39312—2020 铜及铜合金的焊接工艺评定试验 Welding procedure qualification test for copper and its alloys (ISO 15614-6:2006,Specification and qualification of welding procedure for metallic materials—Welding procedure test-Part 6:Arc and gas welding of copper and its alloys,MOD) 2020-11-19发布 2021-06-01实施 国家市场监督管理总局 发布 国家标准化管理委员会