Parça ilavesi ve kaynak yapmadan, metal boru cidarının şekillendirilmesi sureti ile boruda cıvata yuvasının teşkili

摘要

For the process of construction of junctions of prefabricated metal roofs by connecting metal pipe with bolts by special metal elements, to create slot in a metal pipe by shaping walls of pipe ends directly or in various thickness and twisting inwards.