Elimination of cold drawn seamless steel pipe breakage

Foreign precision cold drawn seamless steel pipe is generally added to the metal alloy material way to improve the performance of the cold drawn seamless steel tubes, are required to stress annealing, to eliminate the residual stress material, to improve the organization of materials, improve the plasticity of the material, thus preventing seamless fracture failure occurs purposes.

At present, cold drawn seamless steel tubes are made of ordinary 45 # or 20 # steel 27SiMn steel, cold drawn deformed through the metal strength; however, it is at the expense of metal ductility, toughness for the price. Precision cold drawn seamless steel is its high dimensional accuracy and high strength properties and based on the market, it must ensure that the amount of deformation in a certain range, in order to maximize the performance of materials, to reduce the material adversely affected.

Cold drawn seamless steel pipe deformation is too small to reach the surface finish and dimensional accuracy requirements, but also unable to reach members of the strength index; deformation is too large, seamless plasticity, toughness decreases too much, but the grain is pulled excessively elongate, forming a fibrous tissue, a significant anisotropy metals. Cold drawn seamless steel tube in the axial direction, parallel to the elongate direction of the grain, the intensity increased; cold drawn seamless radially perpendicular to the elongated direction of the grain, but lower strength, and maximum stress of the hydraulic cylinder is present in the radial direction of seamless, so much distortion on the performance of fully drawn tubes unfavorable. For steel and fibrous tissue appears dislocations, vacancies and other crystal defects are generally taken annealing or normalizing heat treatment methods to eliminate them. The purpose is to refine the grain annealing to remove tissue defects, reduce hardness, improved ductility, but also facilitate cold. Annealing equipment of seamless mild steel pipe is indispensable, therefore, to develop an appropriate annealing process is to ensure that cold drawn seamless organization qualified defective product is not a necessary condition for a fracture. If the manufacturers in order to unilaterally reduce production costs, reduce the annealing process is bound to adversely affect the quality of products.