لوهي پائپ لاء ٽيڪنيڪل گهرجن

1. Grade and chemical composition The grade and chemical composition of the steel for galvanized steel pipes shall comply with the grade and chemical composition of the steel for black pipes specified in GB3092. 2. Manufacturing method The manufacturing method of the black tube (فرنس ويلڊنگ يا برقي ويلڊنگ) ٺاهيندڙ طرفان چونڊيو ويو آهي. Galvanizing hot-dip galvanizing استعمال ڪري ٿو. 3.Screw…