HG/T 21521-2014
垂直吊盖带颈对焊法兰人孔
Welding neck flange manholes with davit to vertical cover
2014-07-09
HG/T 21520-2014
垂直吊盖带颈平焊法兰人孔
Slip on flange manholes with davit to vertical cover
2014-07-09
HG/T 21524-2014
水平吊盖带颈对焊法兰人孔
Welding neck flange manholes with davit to horizontal cover
2014-07-09
HG/T 21519-2014
垂直吊盖板式平焊法兰人孔
Plate flange manholes with davit to verticla cover
2014-07-09
HG/T 21523-2014
水平吊盖带颈平焊法兰人孔
Slip on flange manholes with davit to horizontal cover
2014-07-09
HG/T 21518-2014
回转盖带颈对焊法兰人孔
Welding neck flange manholes with hinged cover
2014-07-09