Cold drawing welded tube manufacture process for high-accuracy hydraulic oil cylinder

Abstract

The invention discloses a cold drawing welded tube manufacture process for a high-accuracy hydraulic oil cylinder, which sequentially comprises the following steps of longitudinal shearing, roll bending molding, high frequency welding, welding joint treatment, online eddy current testing, sizing cutting, normalization, pinching, surface treatment, cold drawing, annealing, straightening, defect detection and cutting for measurement. The method is quick in processing molding, high in production volume, free of damage on surfaces in cold drawing and high in manufacture accuracy. After cold drawing, bearing capacity of a welded tube is improved by about 60%, and the welded tube is high in tensile strength and good in elongation rate. Follow-up gold processing amount is reduced, utilization rate of steel materials is improved, and manufacture cost is reduced. The cold drawing welded tube can be directly applied to manufacture of high-accuracy hydraulic oil cylinders.

Description

technical field [0001] The invention relates to a manufacturing process of a cylinder body of a hydraulic oil cylinder, in particular to a process method for manufacturing the cylinder body of a hydraulic oil cylinder by using low-carbon steel and medium-carbon steel. Background technique [0002] In the prior art, the production process of the cylinder body of the hydraulic oil cylinder is generally made of hot-rolled seamless steel pipes, which are produced by the combined cutting process of boring and rolling. Since one of the biggest defects of seamless steel pipes is uneven wall thickness , the main reasons are uneven heating of the tube billet, instability of the centering roll caused by uncorrected piercing machine rolling line, wear of the plug, eccentricity of the rear hole of the plug, incorrect centering hole of the tube billet, excessive bending of the tube billet, etc. For these reasons, it is difficult to solve all the above reasons one by one. Therefore, the y...

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Problems solved by technology

[0003] In the prior art, the welded pipe production process is a relatively mature production technology. However, welded pipes generally cannot be used as cylinder blocks for hydraulic cylinders. The following problems limit their application in the manufacture of hydraulic cylinders: 1) The welded pipe itself The precision of the pipe is relatively low, and its roundness is difficult to be reliably guaranteed; 2) When the welded pipe is welded, the surface weld is easy to handle, but the weld on the inner wall is difficult to handle, especially in an uninterrupted continuous production line. The welding seam on the inner wall is processed, and when it is directly used for the processing of the oil cylinder, there is also the problem of large cutting volume; 3) The weld seam has not been heat-treated, resulting in large internal stress and easy to crack during use; 4) Even if the weld seam passes through Heat treatment, because the welded pipe has not been drawn, its bearing capacity in the axial direction is relatively low, in order to improve its bearing capacity, it is necessary to increase the size, resulting in waste of metal materials