These semi-finished products are among the most common in the industry. They have found application in very important industries because of the combination of rhenium useful properties. High-tech electrical devices are designed using rhenium rods. These are also universal materials that, in addition to being used in equipment, are the initial workpieces for the production of small-diameter round section products.
To buy rhenium rod and round bar in Metotechniсs, just contact us in one of the convenient ways - email, phone, website. We will answer questions related to the product and help to choose the necessary items.
A detailed description of the production methods of these products, grades and recommendations for use are provided on this page in the appropriate sections.
Grades
Products are made of rhenium alloys MR-47 and VR-27 VP. The basis is
molybdenum (Mo) and
tungsten (W), accordingly, and
rhenium (Re) acts as an alloying element.
The percentage of components of the grade MR-47: Mo - at least 52% (the main element), Re - 42-47% (the alloying element); impurities - no more than 0.058%. Among the most weighty impurities are iron (Fe), zinc (Zn), and nitrogen (N). Their mass fraction is no more than 0.01% for each element.
The VR-27 VP grade contains a larger amount of the main component, which is W - at least 69%. The alloying element is also Re, its mass fraction in the alloy is 24-30%. The controlled impurities include molybdenum (Mo) - 0.5%;
niobium (Nb) - 0.01%; calcium (Ca) - 0.01%; carbon (C) - 0.01%, and also
titanium (Ti), aluminum (Al), nitrogen (N), sulfur (S), phosphorus (P) and others.
The chemical composition of MR-47 is described in the standard technical conditions 48-19-254-91; of VR-27 VP - in technical conditions 48-19-274-91.
Production
Rhenium rods and round bars are produced by pressure treatment of the workpieces. The raw material is ingots of rhenium alloys obtained by vacuum melting. This metal is difficult to deform, so the production process is quite long and laborious.
To obtain rods from rhenium, the forging method is used. As in the case of production of items made of other refractory metals (tungsten, molybdenum), this technological operation is performed without heating (cold forging). This is because when heated, rhenium can be oxidized to semioxide (Re
2O
7), which, in turn, contributes to the hot-brittleness of the metal. Hot-brittleness - is the property of metals to crack under hot pressure treatment (forging, stamping, rolling) in the temperature range of red or yellow heat (850-1150 °C).
During the processing of semi-finished products, frequent intermediate annealing is performed. They are performed after each pass, as a result of which the compression of the workpiece is 10-20%. The duration of heat treatment is 3-5 minutes, the temperature is 1700 °C.
A large-diameter rhenium rod (16-50 mm) made of MR-47 alloy is delivered after mechanical processing - its surface is ground.
Product sizes (diameter and length) vary over a wide range of values. So the Ø can be 3-50 mm, and the length - 100-500 mm.
Round bars and rods made of rhenium must meet the requirements of the standards technical conditions 48-19-254-91 and technical conditions 48-19-274-91, which presents the sizes of products and their maximum deviations, mechanical properties, delivery status, marking, packaging and other important parameters.
Very often, a rod of round section is called a rhenium round bar. This is true for products with a quite large diameter. GOST 25501-82 does not contain the definition of a round bar for workpieces and semi-finished products, but in practice this name is often used for rod of round section and large diameter.
Application
The main application of rhenium rods is electrical equipment. This product is used in cases where special reliability and resistance of device components to external influences is required. Specific elements include contacts and brushes of dynamo machines (electric current generators), current interrupters, electrical contacts, and cathodes of electric vacuum devices (for example, oscillating tubes).
Another application of rhenium rods is the production of heaters for high-temperature furnaces for metal sublimation. These heaters must operate in an atmosphere of hydrogen, inert gas, or vacuum. It is worth noting that their service life is 5-10 times longer compared to similar components made of a tungsten-molybdenum alloy.
In general, rhenium rods and round bars are a substitute for tungsten in cases where there are increased requirements for the reliability and service life of parts.
Prices
The availability of rhenium rods and round bars, their price is shown on the
Cost page. The specified products are also available for ordering via the website.