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(Over-burning or not welding), when the hose into the pipe after the force due to uneven steel wire, the pressure in the medium, the virtual, Welded steel wire pull off, can lead to the destruction of bellows drum.
Metal hose in the longitudinal seam weld Weld, porosity, dendritic loose and other defects, so that the effective area of the bellows wall thickness decreases, the strength is not enough to lead to cracking at the weld damage. Carbon steel and stainless steel parts welding, forming a typical small area of the anode parts and large parts of the cathode parts of the adverse environment, easily lead to rapid corrosion failure of materials. Therefore, it is necessary to strengthen the welding process research and welding material selection, to strengthen the welding quality inspection to improve product reliability.
Second, mechanical processing
During the process of welding and forming, the microcracks are cracked on the inner surface of the hose, and in the subsequent assembly test, the micro-cracks are generated in the inner surface of the hose. And the use of micro-cracks in the process of fatigue expansion, and finally failure. Material processing technology and welding process can be improved to avoid the occurrence of micro-cracks.
Third, heat treatment
Heat treatment main role: to improve the cutting performance of metal materials and processing accuracy; improve the fracture toughness of metal materials; reduce metal material cracking. If the heat treatment is not complete, will affect product quality. For example: austenitic stainless steel solution heat treatment temperature of about 1080 ℃, if the solution treatment is not complete, carbide failed to fully solid solution, the material itself has carbide precipitation, will reduce the corrosion resistance and toughness of the material.
To reduce the defects caused by heat treatment, should eliminate the crack to produce conditions, improve the surface compressive stress, improve the quality of metal materials and the appropriate addition of alloying elements.
