GB/T 39246-2020高密度聚乙烯无缝外护管预制直埋保温管件标准
英文:Prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe GB/T 39246-2020...
英文:Prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe GB/T 39246-2020...