Notch-induced cracking method of peeled layer in spinning and deep-drawing of thin-walled tube

Abstract

The invention belongs to the technical field of a spinning drawing technique for a thin-walled tube. In order to solve the problems of a surface quality defect of the pipe fitting caused by the processing obstruction from a stripping layer and even scrapping caused by incapability of drawing under a serious condition when a tube blank spinning drawing mould is used for spinning and drawing the thin-walled tube, the invention provides a gap inducing cracking method for the stripping layer during the spinning drawing process of the thin-walled tube. The method comprises the following steps: (1) prefabricating a gap for the tube blank before drawing, utilizing a sharp-blade cutter to carve a pit with a proper strength at a fillet at the bottom of the outer surface of the tube blank before drawing, wherein the depth is 0.1-0.3mm and the included angle between the blade and the tube wall is at 30-45 degrees, and (2) spinning and drawing the tube blank with the prefabricated gap. The gap inducing cracking method provided by the invention is simple, convenient and low in cost; the method for prefabricating the gap at the bottom of the outer surface of the tube blank before drawing is adopted, so that a function of inducing the stripping layer to crack during a drawing process is achieved; the drawing process originally under whole stripping state is adjusted to be under a crack stripping state.

Description

Technical field [0001] The invention belongs to the technical field of thin-walled tube spinning deep drawing technology, and specifically relates to a method for notch-induced cracking of a peeling layer in thin-walled tube spinning deep drawing. Background technique [0002] During the spinning and deep drawing of the thin-walled tube, excess metal accumulation is formed at the front end of the ball in the spinning deformation zone, which is called the peeling layer. The peeling phenomenon in the spinning process can make the post-spinning tube have good surface roughness and brightness. Peeling is classified into whole peeling, dust peeling, and cracking peeling. From the perspective of the impact on the surface quality of the supination pipe, cracking and peeling is the best state, chip peeling is the worst state, and the overall peeling is in the middle. [0003] The tube blank is generally used such as figure 1 The tube blank spinning drawing die shown is for drawing. The t...

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Problems solved by technology

[0004] The invention aims to solve the technical problem that when using the tube billet spinning and drawing die to carry out the spinning and drawing of thin-walled tubes, the surface quality defects of the pipe fittings caused by the peeling layer hindering the processing are often encountered, and in serious cases, they cannot even be drawn and scrapped , providing a notch-induced cracking method for peeled layers in spinning and deep-drawing of thin-walled tubes

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