Method for preparing cold-push bending elbow

Abstract

The invention relates to a method for preparing a cold-push bending elbow, which comprises the following steps: (1) the inner surface and the outer surface of a pipe billet are covered by using a PE (Polyurethane) film, and the thickness of the PE film covered on the inner surface and the outer surface of the pipe billet is ranged from 0.1mm to 0.5mm, so that friction coefficients between the pipe billet and an inner die as well as between the pipe billet and an outer die are respectively ranged from 0.05 to 0.07; (2) the covered pipe billet is put into the inner die and the outer die to form the elbow in a cold-push bending manner; and (3) the PE film covered on the inner surface and the outer surface of the formed cold-push bending elbow is torn off manually, so that a finished product of the cold-push bending elbow is obtained. The method provided by the invention has the advantages of simplification in operation and pollution free in a preparation process.

Description

technical field [0001] The invention relates to a preparation method of an elbow, in particular to a preparation method of a cold push elbow. Background technique [0002] At present, the forming process of the cold push elbow is to use a special elbow forming machine to put the tube blank into the outer mold. The forming process is completed by moving the remaining gap. The elbow manufactured by the cold push bending process of the inner and outer molds has a beautiful appearance, uniform wall thickness, and small dimensional deviation. [0003] The surface lubrication treatment of the elbow blank in the process of cold push bending elbow preparation is an important link in the cold push bending process. Surface lubricating treatment of cold push-bent elbow blanks can achieve the following effects: reduce the external frictional resistance between the blank and the mold; avoid the bonding phenomenon caused by direct friction between the blank surface and the mold; improve ...

AI Technical Summary

Problems solved by technology

[0004] At present, the lubrication method is usually to coat mineral oil and powder graphite on the inner and outer surfaces of the elbow blank, but this method is difficult to operate and pollutes the environment, especially the subsequent decontamination (mineral oil and powder graphite coated on the inner and outer surfaces of the elbow) is relatively cumbersome