Spiral steel pipes should be subjected to mechanical performance test, flattening test and flaring test before leaving the factory, and must meet the requirements of the standard. The quality inspection methods of straight seam steel pipes are as follows:1. Judging from the surface, that is, in appe

　　1) Small and medium-sized steel bars, wire rods, steel bars, medium-diameter steel pipes, steel wires and wire ropes, etc., can be stored in a well-ventilated material shed, but must be placed on top and under the pad.　　2) Some small steels, thin steel plates, steel strips, silicon steel sheets,

1. Small and medium-sized steel bars, wire rods, steel bars, medium-diameter steel pipes, steel wires and wire ropes, etc., can be stored in a well-ventilated material shed, but must be topped and bottomed.2. Some small steels, thin steel plates, steel strips, silicon steel sheets, small-diameter or

Spiral steel pipe is made by rolling low-carbon carbon structural steel or low-alloy structural steel strip into a tube blank at a certain spiral angle (called forming angle), and then welding the tube seam together. It can be made with a narrower strip Steel produces large diameter steel pipes. Its

Generally speaking, the diameter of spiral steel pipe can be divided into outer diameter, inner diameter, and nominal diameter. The outer diameter of a spiral steel pipe is indicated by the letter D, followed by the size and wall thickness of the outer diameter. For example, a seamless steel pipe wi