Manufacturing method of vehicle seamless steel tubes

Abstract

The invention relates to a manufacturing method of vehicle seamless steel tubes. Surface quality of finished products can be improved through twice phosphorus acid saponification processing and secondary cold drawing processing; during manufacturing, external and internal quality of the products can be guaranteed through twice test, performance index of the steel tubes with the tensile strength larger than or equal to 500Mpa and extension larger then or equal to 10% and internal and external surface roughness smaller than or equal to 0.4 micrometers can be achieved by directly using saw cutting without heat treatment and mechanical machining, requirements of the steel tubes of vehicle parts on strength, toughness and surface quality are met, and meanwhile, technical requirement of processing-free steel tube parent materials of the vehicle parts can be met.

Description

technical field [0001] The invention relates to a method for manufacturing a seamless steel pipe, in particular to a method for manufacturing a special steel pipe for auto parts. Background technique [0002] At present, the existing steel pipes in auto parts usually use 20# carbon structural steel materials, and high-strength steel pipes are obtained mainly through cold working (ie cold drawing or cold rolling) deformation, and their tensile strength is 450-550 Mpa / c㎡ , the extension index is ≥8%, but there is no requirement for surface roughness in the national standard (GB / T3639-2008). Therefore, when using manufacturers to manufacture parts, most of them use seamless steel pipes to increase outer circular cutting (grinding) , The inner hole grinding process makes the base metal meet the requirements of precision and roughness before proceeding to the next step of processing. The outer surface roughness of the produced steel pipe is greater than 0.4 μm, and the grinding p...

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Problems solved by technology

[0002] At present, the existing steel pipes in auto parts usually use 20# carbon structural steel materials, and high-strength steel pipes are obtained mainly through cold working (ie cold drawing or cold rolling) deformation, and their tensile strength is 450-550 Mpa / c㎡ , the extension index is ≥8%, but there is no requirement for surface roughness in the national standard (GB / T3639-2008). Therefore, when using manufacturers to manufacture parts, most of them use seamless steel pipes to increase outer circular cutting (grinding) , The inner hole grinding process makes the base metal meet the requirements of precision and roughness before proceeding to the next step of processing. The outer surface roughness of the produced steel pipe is greater than 0.4 μm, and the grinding process is also required to achieve high-quality base metal steel pipe. Complicated procedures, increasing production costs and reducing production efficiency

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