Constructive features for the warmth rotating forging of precision pipe from alloys on the basis of the molybdenum

Abstract

Myronenko A. Yu. Constructive features for the warmth rotating forging of precision pipe from alloys on the basis of the molybdenum // Herald of the DSEA. – 2019. – № 2 (46). – P. 68–70.

Precision tubes made of molybdenum alloys are mainly used in special purpose equipment related to rocket technology and nuclear power. In this case, the limiting deviations of the individual types of specified pipes by the inside diameter should not exceed 0.01 mm, with the admission field in one side – 0,01 mm. It should be noted that alloys based on molybdenum may be subjected to plastic deformation only at elevated temperatures, at the same time they are characterized by a tendency to gas saturation during heat treatment. Based on the technical characteristics of the current state of the HTTP pipes of an external diameter of less than 6 mm, and especially of alloys based on molybdenum, are manufactured by drawing method, both on the mandrel and without it. However, getting these pipes from molybdenum-based alloys is impossible due to the fact that in order to provide a deformation process, it is necessary to heat both a deformable tube and a working tool up to 450-500˚С. At such temperatures, the strength of the rod holding the mandrel becomes low, and dragging will be accompanied by permanent breakdowns. Drawing on a movable (long) mandrel also does not provide the required precision of the finished pipes due to the fact that when removing the tube from the mandrel, the first is subject to multiple turning on the cutting machine, with the cross-section of the tube is ubiquitous. The purpose of the proposed article is to choose a method for the production of precision tubes made of molybdenum alloys, including those with profile holes (not rounded), as well as the design features of the deformation equipment. The most rational way of manufacturing precision pipes with an external diameter of less than 6 mm, including pipes with a profile (not round) hole, from alloys based on molybdenum is their warm radial wringing using rotational forging machines. To do this, it is possible to use existing rotary-forging machines in view of their modernization: the establishment of the mechanism of feeding the billet, as well as gas vodka for heating the part blank and forging dies.