What methods ensure that seamless steel pipes are properly bent and straightened?

23 Aug,2019

What methods ensure that seamless steel pipes are properly bent and straightened?
　　Achieving minimal curvature in finished seamless steel tubes still relies on mechanical straightening equipment. Therefore, to eliminate curvature in seamless steel tubes, all such tubes must undergo cold straightening.
　　The buckling of seamless steel tubes is caused by improper mill adjustments, residual stresses remaining from the rolling process, and uneven cooling along the tube’s cross-section and length. Consequently, it is impossible to obtain perfectly straight tubes directly from the rolling mill; only cold‑straightening can reduce the tube’s curvature to meet the specified technical requirements.
　　The fundamental principle of straightening is to subject seamless steel tubes to elastoplastic bending, reducing their curvature from a large radius to a small one; therefore, the tubes must undergo repeated bending within the straightening machine. The extent of this repeated bending is primarily determined by the machine’s adjustment settings.
　　Many factors influence straightening quality, including the initial curvature of the tube, the dimensions and material of the steel pipe, the type of straightening machine, and adjustment parameters.

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