Wire and filament are used in spheres where part sizes and high temperature resistance are important. They belong to rolled products of low diameter so as similar tungsten semi-finished products and work under high temperatures efficiently.
Metotechnics Company offers molybdenum wire and filament. For purchasing our products please call us, send a request via e-mail or make an order on the price-list page on our website.
Detailed description of methods of producing these products, grades and application recommendations are given on this page in corresponding sections. Also they contain references for standards that serve as important sources of technical information.
Grades
Semi-finished products are made of MCh, MChVP pure molybdenum grades and of molybdenum-based alloys - TsM2А, TSM3, TSM4 etc. Pure
molybdenum does not contain additional additives; Ts2А includes zirconium and/or
titanium; additives; TSM3, TSM4 - zirconium and
nickel additives.
Chemical composition om MCh, MK and MRN molybdenum wire
Molybdenum grade |
Molybdenum weigh percent, %, at least |
Additive weight percent, % |
Admixture weight percent, %, not more |
MCh |
99.96 |
- |
0.04 |
MK |
99.92 |
Silicon 0.019 - 0.04 |
0.04 |
MRN |
99.92 |
- |
0.08 |
The chemical composition of the above-given grades should comply with requirements of GOST 27266-87, TC 48-19-273-91, TC 48-19-219-76 and other standards.
Production
Molybdenum wire and filament are made by stretching. Rods with diameter less than 3 mm server as primary semifinished products for them. Depending on the diameter and required properties stretching can be made with or without heating the blanks. The first method is used for making hot-drawn molybdenum wire, the second one - for making cool-drawn wire. After stretching annealing can be performed, if required (thermal processing).
Diagram of the wire stretching mill
1 – driving drum, 2 – drawing die, 3 –gas furnace, 4 – grease box; 5 – run-off drum
Products (sizes, properties, supply condition and other technological parameters) should comply with the requirements of several GOSTs and TC such as GOST 27266-87, GOST 18905-73 etc.
It should be mentioned that molybdenum wire with low diameter (usually below 0.1 mm) is usually called molybdenum wire. GOST 25501-82 does not contain the definition “wire” for blanks and semi-finished products, but this term is often used in practice. Also it is often called “wire of micron size”.
Application
Molybdenum wire is applied in many industries, in particular, for making devices for measuring high temperatures such as
tungsten-molybdenum thermocouples. High-purity metals are used for producing them. The junction point at the end of the thermocouples is made with arc welding using a
tungsten electrode. Tungsten-molybdenum thermocouples usually have a protective case. It can be made of zirconium oxide that does not react with thermocouple wire material.
Such
thermocouples allow measuring temperatures over 2000 °С. E.g., tungsten-molybdenum thermocouples were used in experiments for finding the chrome melting point.
Molybdenum wire is used for making filament lamps. It is used for making hooks and loops supporting the tungsten coil and centerpunchers for winding tungsten coil. The material of the supporting hooks and loops should not include iron that can lead to quick darkening of the lamp case. Usually lustrous unannealed or semi-unannealed molybdenum filament and wire with diameter 0.02-1.1 mm and percentage of elongation 5-15%. Application of molybdenum for hooks and loops is determined by molybdenum high durability under high temperatures and retention of plasticity and durability after recrystallization.
The centerpunchers for
tungsten coil winding are made of cleaned unannealed molybdenum wire with percentage of elongation that does not exceed 3%. Also there are some requirements to the blank material durability, blank surface and size tolerances. Thus, it should have a smooth surface, tensile strength about 130 kg/mm
2, its out-of-roundness should not exceed 2% and diameter tolerances should be strictly followed. Tungsten coil is wound on the molybdenum wire centerpuncher and then annealed with the centerpuncher. Annealing conditions require using a high-purity metal as the centerpuncher material. It also should be rather durable after heating and chemically removable. Molybdenum complies with these requirements.
Molybdenum wire and filament is widely used for producing receiving tubes and is used as a construction material. These products are also used for making meshes. As a rule, they are subject to thermal load and should comply with strict requirements for winding accuracy. Molybdenum has a high melting point, is rather form-stable under high temperatures and has some other useful properties that make it widely-used for producing grids of receiving tubes. Also good weldability of molybdenum with nickel should be also mentioned; they are used for making grid supports.
Molybdenum wire and filament for grids should have a clean shiny surface. Blanks can be hard or soft, have 0-20% percentage of elongation and minimum out-of-roundness: the deviations from absolute round section should not increase 1.5%. Hardness and percentage of elongation are determined according to grid production method.
Molybdenum wire is also used for oscillator tubes. Grids, holders for glowing cathodes, resilient elements (e.g., recoil springs for fastening cathodes).
X-ray tubes have cathode bushings made of molybdenum wire and filament that are tightly soldered into the high-fusible borosilicate glass of the X-ray envelope.
Molybdenum wire is used for making
heaters of high-temperature electric furnaces.
Molybdenum heaters are used under temperatures up to 2000 °С. Heating is made in protective atmosphere as molybdenum is easily oxidized.
Prices
The available product range, price, alloy grade, size are given in
Cost section. The general price list for the described products can be found below in a corresponding table.
Material |
Products |
Grade |
Price, $/kg |
Molybdenum |
Wire |
MCh (ЯеО.021.122TC, ЯеО.021.123TC) |
As agreed |
Molybdenum |
Wire |
MChVP (TC 48-19-203-85) |
As agreed |
Molybdenum |
Wire |
MChK (ЯеО.021.122TC, ЯеО.021.123ТУ) |
As agreed |
Molybdenum |
Wire |
MRN (ЯеО.021.123TC) |
As agreed |
Molybdenum |
Wire |
MR-47VP (TC 48-19-254-77) |
As agreed |
Molybdenum |
Wire |
MV-50(IS 11.021.003-76) |
As agreed |