Hot working method for smelting molybdenum rhenium alloy casting ingot by suspending

Abstract

The invention discloses a thermal processing method for suspension electron beam melting molybdenum-rhenium alloy ingot. The method obtains rod-shaped ingot by melting a molybdenum-rhenium alloy sintered bar through suspension electron beam. The high temperature rolling is carried out by the first fire, the parallel ingot is axially fed, with a rolling speed ranging from 300 to 400mm / min, the temperature is kept for 1 hour; the ingot is rolled to the set thickness through rolling for three times and heated at high temperature for the second time, the temperature is kept for 1 hour, with a rolling speed ranging from 300 to 400mm / min; the ingot is rolled to the set thickness after inverting the direction; the ingot is heated at high temperature for the third time, the temperature is kept for half an hour; the ingot is rolled to the set thickness through 3 rolling for three times and is carried for cold rolling after annealing. The thermal processing method provided by the invention reduces the dislocation movement for single sliding and the speed of the dislocation movement, controls the direction of the dislocation movement, avoids the cracking at crystal boundary owing to the accumulation of the dislocation; besides, the thermal processing method ensures cogging of the ingot but not cracking, and ensures heating processing to go on smoothly. By the thermal processing method, accepted plank stuff characterized by fine crystal particles and uniform sizes can be made, with purity over 99.99 percent.

Description

technical field [0001] The invention belongs to the technical field of metal pressure processing, and relates to a thermal processing method for alloy ingots, in particular to a thermal processing method for suspension melting molybdenum-rhenium alloy ingots. Background technique [0002] Molybdenum-rhenium alloy materials used in electric vacuum devices have high requirements on impurity content, especially gas impurity content. The purpose is to reduce the outgassing of materials at high temperatures and improve the performance stability and service life of components. The most effective way to reduce impurity content and improve material purity is to carry out electron beam suspension melting on raw materials. This melting method uses electron beam bombardment in a vacuum chamber to melt the material, and the lower base extends out of the crucible to accept the molten material. The surface tension keeps the molten pool stable and does not overflow. With the bombardment, t...

AI Technical Summary

Problems solved by technology

[0003] However, everything always has two sides. Electron beam suspension smelting also brings unfavorable factors while improving the purity, which is that the crystal grains of the ingot are very coarse.

For molybdenum-rhenium alloys, the crystal grains are particularly easy to grow during smelting, and sometimes a bunch of dendrites appear from the beginning to the end, and the single grain size can reach Above, such a large grain brings great difficulties to pressure processing

Thermal billet opening by forging is prone to intergranular splitting, and it is difficult to process into materials

Extruded blanking material bears compressive stress, and the processing effect will be better, but there are certain requirements for the size of the ingot. When the size of the ingot is small or large, extrusion blanking cannot be performed.