Each steel pipe has unique product quality defects in seamless steel pipe production is folded inside the main quality defects are generated during the perforation and can not be eliminated. Is folded inside the folding tube inner surface, the appearance is characterized by scaly layer, similar to a closed curve, in addition there are irregular shaped folds. Folding in the rolling process is the poor quality of the metal produced when there is excessive segregation of non-metallic inclusions, the pores will be concentrated in the periphery of metallic inclusions, is formed in the perforated inner split folding process, through fixed Drive machine It scaly after extrusion or other shapes appears. In short, rolled Galvanized Steel Pipe
round billet of substandard quality are mainly non-metallic inclusions and harmful substances caused by the high degree of metal contamination. Furthermore blank segregation in the blank strip casting quality is extremely important implications. The ribbon segregation depends largely on the chemical composition of steel, insulating state and the cooling rate. Steel, increasing the content of harmful elements in the segregation band to promote their concentration increased, thus forming segregation. In addition, the increase in carbon content also exacerbate the segregation of impurities especially manganese. During piercing the following factors also affect the internal fold, 1 fold perforation of internal deformation parameters, produce hot-rolled seamless steel pipe folding a certain relationship with the piercing process, piercing process parameter settings, the tool design, have a certain influence on the generation folding, tube rupture not only with the center roll and the total reduction in the total reduction former head related transfer tube and a half weeks with a partial reduction related. 2, the perforated inner fold temperature effects: With the temperature increasing, the plastic material to improve the critical amount of reduction increases with temperature increase, but if the use of the casting tube optimum casting temperature, the temperature at a perforation within the range of Galvanized Steel Pipe Supply
variation is no significant change in off. 3, the heating time and the relationship within the fold, in baked prolonged heating temperature is constant inward folding little effect, but the number has significantly increased the outer fold, because the longer the heating grain grew more powerful, but the surface is more Obviously, the organization produced outside the fold performance deterioration. 4, the tool inward fold impact, head inward folding also have some impact, for example, the head can reduce their use of nasal cavity formation and improve the quality of the inner surface, while the shape of the head also have some impact on the quality of the tapered head will from the head to the tip of the hole part of the reduction increases, which have an adverse effect on the waste pipe; spherical head tube is able to ensure that waste reduction is reduced along the feed direction, to improve the quality of waste pipe. The best head shape should be able to ensure that the deformation zone along the length direction of the waste pipe wall thickness reduction unchanged. Finally, to improve the quality of the inner surface, to reduce internal aspects should hand off: casting tube to Galvanized Steel Pipe Manufacturers
ensure uniformity of the organization, reduce segregation to prevent the excessive concentration of non-metallic inclusions; using optimum casting temperature, to increase the critical reduction; perforation former billet heating temperature decreases guarantee top front reduction, improve the quality of heat tools.
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