Bending and horizontal type reshaping method of high-pressure bend

Abstract

The invention relates to a bending and horizontal type reshaping method of a high-pressure bend, mainly comprising the following steps of: 1, feeding a tube blank with the outer diameter of D(1+delta) and same wall thickness as that of the bend; 2, heating a straight tube blank into a austenite structure, and then placing on a concave mould of a bending mould preheated to 200-300 DEG C, wherein aconvex mould downwards moves with a cross beam positioned on a press till the convex mould and the concave mould are closed for pressing bending deformation, after the bending mould is closed, the section of a cavity perpendicular to an axial line is in the shape of an ellipse, a long axis of the ellipse is 1.2 times of the nominal diameter of the bend, a short axis of the ellipse is 0.8 times ofthe nominal diameter of the bend, and the bending radius of the middle of the convex mould is set to be 1.5-2.0 times of the radius of the bend to prevent the contact area of the middle of the tube blank and the convex mould from collapses so that the tube blank is integrally bent and the section of the tube blank is changed into the shape of the ellipse at the same time; 3, horizontally placing the tube blank which is initially formed after being bent in a concave mould cavity of a reshaping mould preheated to 200-300 DEG C, wherein the motion direction of the long axis of the sectional ellipse of the tube blank is the same as that of a reshaping convex mould, the reshaping mould is combined vertically so that the tube blank undergoes circumferential compression, and the elliptical section of the tube blank is reshaped into a circular section. According to the invention, the production efficiency is greatly enhanced, and the designing and processing periods of a mould are shortened; in addition, the bending and the reshaping moulds are simple and are easy to operate, so that vast manpower and material resources are saved.

Description

technical field The invention relates to a compression molding method, in particular to a compression molding method for high-pressure pipe elbows. Background technique The elbow is a prominent weak link in the piping system, and the reliability of the pipeline is mainly determined by the working capacity of the elbow. At present, there are three commonly used production methods for high pressure elbows: pushing, bending and pressing. Pushing is the most common production method, but this process method cannot realize the forming of elbows with straight ends; the bending method will reduce the wall thickness of the tube blank, and it is not suitable to produce elbows with a small radius of curvature. The existing internal support bending forming method is mainly: heating the straight pipe blank with the same diameter as the elbow to 800°C, placing it on the lower die, putting spacers in the inner cavity of the tube blank, and placing For the plug, in order to ensure the po...

AI Technical Summary

Problems solved by technology

Therefore, there are following deficiencies in this bending forming method: 1. There are many mold accessories, the preparatory work for pressing is loaded down with trivial details, and the production efficiency is low

2. Generally, more than two operators are required, and they work for a long time in a high temperature environment

3. This method is also not suitable for the production of elbows with straight ends