Manufacture of special pipes by the method of heading

Abstract

In spite of the success, achieved in the production of metal pipes, its further progress and improvement still remain a problematic issue due to the development of techniques and new technologies.For the manufacture of barrels and special pipes of military shooting weapons, belonging to the small serial production is considered advisable applying the technological process of heading which is staying out by relatively simple technology and a small number of used equipment.The experimental studies have shown that during hot heading, wearing and overheating processes are taking place of press mold elements. Especially in difficult conditions, a pipe mandrel works, when is heated up to 800-1200 Celsius in the middle of the specimen, after which it loses strength and sometimes under the action of tensile stress causes destruction. Based on this, the temperature factor has a great influence on the stability of the press mold; therefore, the use of a cooling system is of great importance. For this purpose, the press molds were designed and then manufactured in an aviation enterprise for heading of work piece with a diameter of 50 mm.The process was divided into two stages to simplify the heading regime. The shell is obtained in the first stage, and the pipe is made from this shell in the second stage. It's necessary that the work piece is being given the opportunity for radial expansion for the rational carrying out of the process of obtaining a shell, otherwise, the metal will begin to flow in the opposite direction of the punch and we will get reverse heading. To avoid this phenomenon, the specimen was given the shape of a polyhedral prism, for the purpose that the sectional area of the work piece would be less than the sectional area of the matrix.In this paper, based on the results of theoretical and experimental studies, press molds for industrial use have been worked out for the production of special pipes and pipe work pieces by the reverse heading method.In the work, the given design of the press form consists of a water cooling system, which protects the elements of the press mold from heating and, accordingly, significantly increases the duration of its work, which in turn gives a significant economic effect.