CN101269383A - Hot working method for smelting molybdenum rhenium alloy casting ingot by suspending - Google Patents

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

A kind of hot-working method of smelting molybdenum rhenium alloy casting ingot by suspending

Technical field

The invention belongs to the stress metal processing technique field, relate to a kind of hot-working method of alloy cast ingot, be specifically related to a kind of hot-working method of smelting molybdenum rhenium alloy casting ingot by suspending.

Background technology

The molybdenum rhenium alloys material of being on active service in electron tube is to impurity content, and particularly gaseous impurity content has very high requirement, and purpose is to reduce the venting of material under the condition of high temperature, improves the stability and the service life of components and parts.And the minimizing impurity content, improving the effective method of material purity is that raw material is carried out electron beam smelting in suspension, this melting mode utilizes the interior beam bombardment material loading of vacuum chamber to make its fusing, the bottom base stretches out outside the crucible, accept the fusion material loading, abutment surface tension force is kept the molten bath and is stablized and not overflow, along with the loading and unloading of carrying out of bombardment effect descend steadily, keep the molten bath and finally obtain the melting ingot casting in a FX, whole fusion process material does not contact crucible, has avoided the pollution of crucible, and smelting time is longer, impurity element is fully volatilized, taken away by vavuum pump.Therefore, the purity of melting ingot casting is very high, generally can reach more than 99.99%.

Yet anything always has dual character, and electron beam smelting in suspension has also brought adverse factors when improving purity, and the crystal grain of Here it is ingot casting is very thick.For the molybdenum rhenium alloys, crystal grain is grown up especially easily during melting, and occurring sometimes from first to last is a branch of dendritic crystal, and single-crystal grain size can reach

More than, so big crystal grain has brought very big difficulty to pressure processing.Adopt the hot cogging of method of forging, be prone to along brilliant splitting, very difficult processing is become a useful person.The extrusion blooming material bears compression, and processing effect can be quite a lot of, but the ingot casting size is had certain requirement, when small-sized or very big, can't carry out extrusion blooming when ingot casting.

Summary of the invention

The objective of the invention is to deficiency, provide a kind of technology simple, can avoid the hot-working method of ingot casting in the cogging process, to obtain tiny, the uniform molybdenum rhenium alloys of the size sheet material of crystal grain along the smelting molybdenum rhenium alloy casting ingot by suspending of brilliant splitting at existing process technology.

To achieve these goals, the technical solution used in the present invention is: a kind of hot-working method of smelting molybdenum rhenium alloy casting ingot by suspending is characterized in that its hot procedure is:

With powder metallurgy molybdenum rhenium alloys bar is raw material, and wherein the percentage by weight of molybdenum, rhenium is Mo50-80%, Re20-50%, molybdenum rhenium alloys bar is put into vacuum drying oven carry out electron beam smelting in suspension, obtains the round bar shape ingot casting, and hot rolling is carried out in the back that strips off the skin on plate mill; The first fire time rolling temperature is 1200 ℃～1800 ℃, is incubated 1 hour, the axial feeding of parallel ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus is controlled at 45-55%; The second fire time rolling heating-up temperature is 1200 ℃～1800 ℃, is incubated 1 hour, the vertical axial feeding of ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus 55-65%; 1100 ℃～1700 ℃ of the 3rd fire time heating-up temperatures are incubated 30 minutes, the vertical axial feeding of ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus 65-75%, the annealing back changes cold rolling.

The present invention adopts the method for direct rolling-cogging, has reduced single slide surface dislocation motion amount, has reduced dislocation motion speed, has controlled the dislocation motion direction, and the crackle of having avoided the pile-up of dislocation of crystal boundary place to produce can prevent intergranular crack effectively.The main points that the operation of rolling need be grasped are as follows:

At first, control feed direction, that is: the axial feeding of first fire time necessary parallel ingot casting.Under the effect of roll-force, shearing slip with the plane at the axial angle at 45 of dendritic crystal on take place, the slippage area is less, can not form splitting on a large scale.

The second, suitably reduce roll rotational speed, rate of deformation is reduced, percussion reduces, and shearing slip can be distributed on one group of parallel slide surface, and the slippage of each aspect is reduced, dislocation motion speed reduces, and the possibility that dislocation pile up forms crackle reduces.

The 3rd, suitably reduce reduction in pass, action principle also is that slippage is reduced, and the dislocation pile up degree reduces, and the possibility that cracks reduces.

The 4th, suitably improve rolling temperature, material plasticity is improved, action principle is the ability enhancing that material adapts to detrusion, the possibility that cracks reduces.

The 5th, heat time heating time of proper extension second fire time, Deformation structure's recovery and recrystallization that the first fire time hot-working is formed becomes tiny equiax crystal, and fine-grained material bears the ability of external force and strengthens, the possibility of cracking reduces.The second fire time axial feeding of rolling vertical former ingot casting, at this moment because of material recovery and recrystallization is tiny equiax crystal but not dendritic crystal, it is rolling not easy to crack to commutate.The commutation feeding can make board dimension control flexibly, obtains the sheet material of required specification.

The present invention compares with existing hammer cogging technology and has the following advantages: adopt higher heating-up temperature, and long-time insulation, lower mill speed, the axial feeding of parallel ingot casting, light reduction, multi-pass is rolling; The second fire time high temperature long-time heating, it is rolling to commutate, percussion when having avoided forging, reduced single slide surface dislocation motion amount, the crackle of having avoided the pile-up of dislocation of crystal boundary place to produce, can guarantee that cogging do not split, guarantee that hot procedure carries out smoothly, can obtain that crystal grain is tiny, the uniform qualified sheet material of size.

Describe the present invention in detail below by embodiment, but protection scope of the present invention is not limited only to following examples.

The specific embodiment

Embodiment 1

By weight percentage, Mo59%, Re41% in the molybdenum rhenium alloys put into vacuum drying oven with molybdenum rhenium alloys sintered bar and carry out electron beam smelting in suspension, obtain Φ 30 * 300mm ingot casting; Hot rolling on plate mill, the hydrogen furnace heating, 1200 ℃～1800 ℃ of temperature are incubated 1 hour.The first fire time axial feeding of rolling parallel ingot casting, the roll linear velocity is 400mm/min, rolls thickness 15mm through three passages.Second fire is heated to 1200 ℃～1800 ℃, is incubated 1 hour, roll linear velocity 400mm/min, and the vertical axial feeding of ingot casting is rolled down to thickness 7mm.1100 ℃～1700 ℃ of the 3rd fire time heating-up temperatures are incubated 30 minutes, are rolled down to thickness 3mm, and the annealing back changes cold rolling.Make that crystal grain is tiny, the uniform qualified molybdenum rhenium alloys sheet material of size, purity reaches more than 99.99%.

Embodiment 2

By weight percentage, Mo75%, Re25% in the molybdenum rhenium alloys put into vacuum drying oven with molybdenum rhenium alloys sintered bar and carry out electron beam smelting in suspension, obtain Φ 30 * 300mm ingot casting, hot rolling on plate mill, hydrogen furnace heating, 1200 ℃～1800 ℃ of temperature are incubated 1 hour.The first fire time axial feeding of rolling parallel ingot casting, roll linear velocity 400mm/min rolls thickness 15mm through three passages.1200 ℃～1800 ℃ of the second fire time heating-up temperatures are incubated 1 hour, roll linear velocity 400mm/min, and the vertical axial feeding of ingot casting is rolled down to thickness 7mm.1100 ℃～1700 ℃ of the 3rd fire time heating-up temperatures be incubateds 30 minutes, and it is thick to be rolled down to 3mm, and the commentaries on classics of annealing back is cold rolling, make that crystal grain is tiny, the uniform qualified molybdenum rhenium alloys sheet material of size, and purity reaches more than 99.99%.

Embodiment 3

By weight percentage, Mo59%, Re41% in the molybdenum rhenium alloys put into vacuum drying oven with molybdenum rhenium alloys sintered bar and carry out electron beam smelting in suspension, obtain ingot casting size Φ 45 * 300mm; Hot rolling on plate mill, the hydrogen furnace heating, 1200 ℃～1800 ℃ of temperature are incubated 1 hour, roll linear velocity 300mm/min, the first fire time axial feeding of rolling parallel ingot casting, it is thick to roll 25mm through three passages.Inferior 1200 ℃～1800 ℃ of second fire is incubated 1 hour, roll linear velocity 300mm/min, and it is thick that the vertical axial feeding of ingot casting is rolled down to 10mm.The 3rd fire times 1100 ℃～1700 ℃ be incubated 30 minutes, mill speed 400mm/min, and it is thick that three passages are rolled 3mm, and the commentaries on classics of annealing back is cold rolling, makes that crystal grain is tiny, the uniform qualified molybdenum rhenium alloys sheet material of size, and purity reaches more than 99.99%.

Claims (1)

1, a kind of hot-working method of smelting molybdenum rhenium alloy casting ingot by suspending is characterized in that its hot procedure is:

With powder metallurgy molybdenum rhenium alloys bar is raw material, and wherein the percentage by weight of molybdenum, rhenium is Mo50-80%, Re20-50%, molybdenum rhenium alloys bar is put into vacuum drying oven carry out electron beam smelting in suspension, obtains the round bar shape ingot casting, and hot rolling is carried out in the back that strips off the skin on plate mill; The first fire time rolling temperature is 1200 ℃～1800 ℃, is incubated 1 hour, the axial feeding of parallel ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus is controlled at 45-55%; The second fire time rolling heating-up temperature is 1200 ℃～1800 ℃, is incubated 1 hour, the vertical axial feeding of ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus 55-65%; 1100 ℃～1700 ℃ of the 3rd fire time heating-up temperatures are incubated 30 minutes, the vertical axial feeding of ingot casting, and roll linear velocity 300～400mm/min, rolling through three passages, total working modulus 65-75%, the annealing back changes cold rolling.