Some crack extension probably developed from the unfused section of the butt weld across the thickness of the stiffener during transport and erection. 有些裂紋可能在運輸和安裝過程中就從加勁肋對接焊未熔透處開始發展。
This standard covers the procedures for the heat joining of pipe and fittings made from polyolefin materials utilizing either the socket or butt fusion methods. 這個標準涵蓋採用承插熱熔和對焊熱熔方法對聚烯烴材料管道和連接件進行熱連接的程序。
