X80电阻焊管线管
X80 grade electric resistance welding linepipe
地下管线管理
underground pipeline management
Management of Underground Pipelines
地下管线管理系统
underground pipeline management system
钩形集极晶体管管线
hook collector transistor
管线管理系统
tubeline management system
管子-管板
Tube to Tubesheet
tube to tubesheet auto-GTAW
管子—管板焊缝
the Welds between Tube and Tubesheet