Copper tube diameter expansion drawing wall thickness control method

Abstract

The invention relates to a copper tube diameter expansion drawing wall control method. The method comprises the steps that firstly, the tube blank raw material specification and the inner mold calibration bench diameter are determined, then, an experience formula is used for calculating the tube blank drawn wall thickness under the condition that no outer mold exists, and finally, according to thenon-outer-mold drawn wall thickness and the current-pass target wall thickness, the inner diameter of an adopted outer mold calibration bench is determined. The non-outer-mold drawn tube blank wall thickness calculation method and the calculation method for the outer mold calibration bench inner diameter for the target thickness during inner and outer mold diameter expansion drawing are summarized according to production experience of the inventor for many years, are adopted as the direct basis for diameter expansion drawing mold design and are used for precisely controlling the tube wall thickness obtained after each-pass drawing, the error rate is lower than 0.5%, the direct basis can be supplied to large-caliber white copper tube diameter expansion drawing pass deformation rate distribution, annealing technology design and drawing mold design, and the method has the important engineering practical value.

Description

technical field [0001] The invention relates to a diameter-expanding technology of a copper pipe, in particular to a method for controlling the wall thickness of a copper pipe for diameter-expanding drawing. Background technique [0002] Large-diameter white copper tubes are key structural products required in the field of marine engineering. At present, only a small number of domestic enterprises have the production capacity of such products. Pipes for marine engineering have high requirements in terms of corrosion resistance, air tightness, and weldability, so white copper pipe products need to have relatively high precision in terms of shape and size. Large-diameter seamless white copper tubes are generally produced by "extrusion-cold rolling-drawing" technology. Usually, the final forming of the production of small-diameter pipes generally adopts ordinary fixed short cores, long core rods or floating cores for diameter reduction drawing, while for large-diameter seamles...

AI Technical Summary

Problems solved by technology

Among them, drawing without external mold is a processing method with low precision, because when drawing without external mold, the mold only controls the expansion of the inner diameter of the tube blank, while the direction of the outer diameter of the tube blank is free to deform, how does its wall thickness change? , parameters such as deformation after drawing are affected by various factors such as tube blank size, boundary friction, alloy state, springback, etc., and are usually difficult to accurately predict and control

In the process of expanding the diameter with an outer mold, under the simultaneous action of the outer mold and the core mold (inner mold), it is theoretically possible to achieve complete control of the inner and outer diameters and wall thickness. However, in actual production, Due to the unclear relationship between the specifications of the inner / outer mold, the inner diameter of the pipe and the wall thickness, it is difficult to accurately grasp the design of the outer mold size, which easily leads to the technical problem of inaccurate control of the pipe wall thickness after drawing

If the inner diameter of the working zone of the outer mold (the inner diameter of the sizing zone) is too large, it may not be able to touch the outer wall of the tube blank and cannot limit the wall thickness; if the inner diameter of the working zone of the outer mold (the inner diameter of the sizing zone) is too small, it may Due to the large diameter reduction deformation rate, the drawing force and deformation inhomogeneity and instability are significantly increased. In severe cases, the pipe may be broken, and the outer surface of the product may be damaged, which seriously affects the surface quality of the pipe after diameter reduction drawing.

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