VA tungsten wire micron 8 - 500 microns

International Equivalent

Mark	Analogue	Aisi Uns	En	Order
VA	EHF	WP	EWP	Delivery from the stock, in stock
VRN				Delivery from the stock, in stock
BT-7			WThO0.7	Delivery from the stock, in stock
BT-10			WThO1	Delivery from the stock, in stock
VT-15				Delivery from the stock, in stock

It would seem that what could be simpler than wire - one of the most popular rolled metal products? Especially since, as Oscar Wilde said: In life, the simpler, the truer. However, the production of tungsten wire is associated with a number of difficulties.

Advantages .

It is made of the most refractory of metals with a melting t° of +3422°C. Tungsten has high strength, heat resistance and resistance to aggressive industrial environments. Such wire retains hardness under severe heat, wear resistance and has a minimal coefficient of thermal expansion, which allows it to be used for the most demanding products. The wire has the highest compressive and tensile modulus, high electrical resistance and remarkable thermal conductivity. Wear resistance, high temperature creep resistance have made it indispensable in modern industry.

Production

Group A, B, C (black) wire of VA, BPH, HPH grades is manufactured by means of powder metallurgy technology. Powder rods, which are heated and forged by a rotary forging machine to a diameter of 1-10 mm, serve as a billet. The thinner wire is called yarn. Chromium, cobalt and carbon may be added to its composition. In this case its strength is increased by 30%. 1 gram of tungsten is rolled into a filament 3.5 meters long, enough to make 700 60-watt lamps. This satisfies the needs of the world's electrical industry with 2 rail cars of tungsten per year.

Applications

Tungsten wire of ВМ grade is used for production of cathodes and heaters of electronic devices for radioelectronic and X-ray equipment. It is shock and vibration resistant at the temperature up to 2100°C. BPH grade is used for springs, hooks, cathodes of electronic and gas-discharge devices, bushings, traverses and other parts that do not require tungsten with special additives. Because of its high electrical resistance and unique light output, tungsten filament is indispensable in lighting devices. Tungsten filament for light sources is produced according to GOST 19 671-91 of VA, BC, BPH grades with diameter of 19,5 microns - 1,5 mm. It is used for production of spiral cathodes of electronic devices, springs of electronic and semiconductor devices, loop-shaped non-spiral cathodes, heaters, etc . Tungsten grids and filters are used in the chemical industry. Tungsten wire is used not only for production of surgical instruments. In mechanical engineering, textile industry, aircraft and rocket construction the most important units are made of it. Non-melting tungsten electrodes are extremely heat-resistant and operationally reliable. They allow to join sheets of steel, copper, aluminum, brass with a thin and even seam.

TUNGSTEN WIRE GOST 18 903-73

Tungsten grade	Group	Surface condition	Ø, micron	Designation
VA	А	Black	10 - 1500	Lamp spirals. Spiral-shaped cathodes and heaters of electronic devices, springs of semiconductor devices.
VA	AD	Black with enhanced processability	50 - 1500	Cathode preheaters and straight wound cathodes of spiral design with core factor 1 - 2,2
VA	AE	Black with enhanced heat resistance	500 - 1200	Spiral wound straight cathodes and cathode preheaters with operation t° or heat treatment t° above 2000°C
VA	AP	Black	10 - 200	Loop preheaters, grids and springs of electronic devices, non-spiral cathodes.
VA	Б	Cleaned	11 - 500	Supports, hooks, springs, incandescent lamp spirals, loop heaters, and cathodes of electronic and gas discharge devices.
VA	Г	Cleaned and annealed	11 - 500	Loop heaters, grids, nonspiral cathodes. Spirals of some special incandescent lamps
VA	Т	Etched	5 - 12	. Grids of electronic devices Cathode warmers and direct-fed spiral and non-spiral cathodes.
VA	TO	Etched and annealed	5 - 12	. Grids of electronic devices Cathode warmers and direct-fed spiral and non-spiral cathodes.
VM	А	Black	11 - 1500	Spirals of special incandescent lamps and parts of devices operating at t° up to 2100 °C under increased mechanical loads (shock, vibration).
VRN	А	Black	800 - 1500	Inlets, beams and other parts that do not require tungsten alloy.
VT-7	А	Black	20 - 1500	Springs, hooks, cathodes of some electronic and gas-discharge devices.
VT-10	А	Black	25 - 1500	Cathodes of some electronic and discharge devices
VT-15	А	Black	150 - 1500	Cathodes of electronic and gas-discharge devices

Buy at the best price

Evek GmbH stocks a wide range of high quality tungsten cathodes at a price to suit every customer. Preferential discounts are available for bulk orders.