Seamless steel pipe fracture treatment method

Seamless steel pipe fracture treatment method

Domestic high-precision seamless steel pipes generally improve the performance of materials by adding metal alloys. The seamless steel pipes after cold drawing need to be stress annealed to eliminate the residual stress of the material, improve the tissue material, and increase the plasticity of the material, so as to prevent The purpose of fracture failure of seamless steel pipe.

At present, my country's stainless steel seamless pipes are all made of ordinary 45# or 20# steel 27SiMn steel, and the metal strength is improved through cold drawing deformation; however, this is at the expense of the plasticity and toughness of the metal. Precision cold-drawn seamless steel pipe is based on the market due to its high dimensional accuracy and high-strength performance. It must ensure that the deformation is within a certain range in order to maximize the performance of the material and reduce the negative impact on the material.

If the deformation of the seamless steel pipe is too small, it cannot meet the requirements of surface finish and dimensional accuracy, and cannot meet the strength index components; if the deformation is too large, the ductility and toughness of the seamless steel will decrease too much, and the grains will be excessively elongated to form fibers Organization, the metal will produce obvious anisotropy. The cold-drawn seamless steel pipe is axially elongated parallel to the grain direction to increase the strength; the radially stretched seamless steel pipe is perpendicular to the elongation direction of the grain, but the strength is low, and the largest water stress exists in the seamless steel pipe In the radial direction, the deformation is too large, and the performance of the negative cold drawn tube cannot be fully exerted.

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