UDC621.791J33中华人民共和国国家标准GB/T12469-90焊接质量保证钢熔化焊接头的要求和缺陷分级Quality assurance of welding-Requirement for fusion welding joint of steel and classification for imperfection1990-09-08发布1991-10-01实施国家技术监督局发布
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