GB/T 34020.3-2017双层卷焊钢管第3部分:空调和制冷设备管路系统用管国家标准
英文:Double wall copper-brazed steel tubes—Part 3: Tubing system for air conditioner and refrigeration GB/T 34020.3-2017介绍...
英文:Double wall copper-brazed steel tubes—Part 3: Tubing system for air conditioner and refrigeration GB/T 34020.3-2017介绍...