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 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 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