1. Welding quality
Corrugated pipe, reinforcing ring and steel wire net in the process of welding wire to weld phenomenon (burning or not, when welding) hoses into the pipeline after the wire due to uneven stress, in the medium under pressure, weld wire pull, can lead to destruction of the corrugated pipe drum.
Corrugated metal hose of stainless steel tube in the longitudinal seam weld, porosity, dendrite porosity and other defects, the effective area of corrugated pipe wall thickness decreases, which led to the destruction of the weld seam cracking strength is not enough. Carbon steel and stainless steel parts are welded, forming typical small area anodic parts and large area of cathode parts, which are unfavorable to contact, which will lead to rapid corrosion failure of materials. So we should strengthen the link of welding process research and welding material selection, strengthen the welding quality inspection, in order to improve the reliability of products.
Two. Mechanical processing
Materials in the rolling process due to wave force is not uniform, easy to produce micro cracks in the inner surface of the crest with regularity, and in the welding process, the micro crack on the tube surface, in the subsequent assembly test and in the process of using micro crack fatigue propagation and final failure. The improvement of the material processing technology and welding process can avoid the production of micro cracks.
Three. Heat treatment
The main effect of heat treatment is to improve the cutting performance and machining precision of metal materials, improve the fracture toughness of metal materials and reduce the cracking of metal materials. If the heat treatment is not complete, it will affect the quality of the product. For example, the solid solution heat treatment temperature of austenitic stainless steel is about 1080 degrees. If the solid solution is not complete, the carbide is not fully dissolved, and the material itself has carbide precipitation, which will reduce the corrosion resistance and toughness of the material.
In order to reduce the defects caused by heat treatment, the conditions of crack generation should be eliminated, the surface pressure stress should be improved, the quality of metal materials is improved and the alloying elements should be added properly.