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Elimination of Fracture of Cold Drawn Seamless Steel

Sources: this site    Click:    Date: 2017-4-13 1:45:33

High precision cold drawn seamless steel pipe is generally through the metal in the way to increase the alloy to improve the performance of materials, seamless steel pipe in the cold drawn after the need for stress relief annealing to eliminate the residual stress of the material to improve the organization of the material, Improve the plasticity of the material, so as to achieve the purpose of preventing the failure of seamless steel pipe fracture.

At present, China's cold drawn seamless steel pipe materials are ordinary 45 # or 20 # steel 27SiMn steel, through the cold drawn deformation of the metal strength to improve; but it is at the expense of metal plasticity, toughness at the expense of. High-precision cold drawn seamless steel pipe is based on its high dimensional accuracy and high strength performance based on the market, it must ensure that the deformation within a certain range, in order to maximize the material performance, reduce the material Negative Effects.

Cold-drawn seamless steel pipe deformation is too small, can not meet the surface finish and dimensional accuracy requirements, but also can not achieve the strength index of components; deformation is too large, seamless steel pipe plasticity, toughness reduced too much, and the grain was too much Slender, forming a fibrous tissue, the metal will have a significant anisotropy. The vertical direction of the cold drawn seamless steel pipe is perpendicular to the elongation direction of the grain, but the strength is reduced, and the maximum stress of the hydraulic cylinder Is present in the radial direction of the seamless steel pipe, so the deformation is too great for the full play of the performance of the cold drawn tube.

For the emergence of fiber in the steel and dislocation, vacancy and other crystal defects, are generally taken by annealing or normalizing heat treatment means to be eliminated. The purpose of annealing is to refine the grain, eliminate tissue defects, reduce hardness, improve the plasticity, but also easy to cold processing. Cold-drawn seamless steel pipe production, indispensable annealing equipment, therefore, to develop a suitable annealing process, is to ensure that cold-drawn seamless steel pipe organization qualified, the product does not appear the necessary conditions for fracture defects. If the manufacturer in order to reduce production costs one-sided, reduce the annealing process, will inevitably adversely affect the quality of the product.