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RAV ABJ 900

Vacuum Arc Remelting Installation type MRF ABJ 900

Description, technical characteristics, main components, performance of the installation

Vacuum Arc Remelting Installation MRF ABJ 900 provides the possibility of melting (obtaining) of metallic materials in controlled atmosphere of argon, after vacuum achievement in working enclosure up to values 10-5 mbar, through a mobile non-consumable tungsten electrode thoriated.

 

Vacuum arc furnace ABJ 900 provide a cost saving alternative to resistance or inductance heating furnaces for many applications.

 

Rather than heaters with resistence, or induction coils, an electric arc is used to heat up and/or melt parts, especially when subjected to heating process small quantities of materials.

 

Vacuum arc furnace ABJ 900 can instantly reach at temperatures over 3500ºC, and will cool to room temperature within minutes. It is simple to use, highly reliable and economical in working.

Technical characteristics of the installation MRF ABJ 900

Vacuum Arc Remelting Installation MRF ABJ 900

1. Furnace Chamber

Furnace Chamber (vacuum container) is made of stainless steel 304L and is equipped with double wall water cooled (temperature below 50ºC). Chamber bottom is made of aluminum with a thickness of 20 mm. It is placed above the electric generator to minimize the volume and surface of installation.

 

The loading of installation is done on the bottom of the stand working by opening of articulated bell, and loading of materials in customized cavities in hearth plate made of copper.

 

Loading of materials for production and refining, and unloading of samples taken, runs slightly by lifting the bell cover who is caught with a hinge on the furnace chamber.

Viewing of crucible and electrode can be done through window in diameter of 4 '' placed in the front of the installation.

Bell cover in closed position

Bell cover in open position

The illumination of the work space during operation of installation is through a window with a diameter of 1'', placed in the rear of the container working with a halogen lamp included.

 

Viewer window is fitted with a hinged glass welding to protect eyesight during smelting and refining of metallic charge.

 

Connection to the vacuum pump is through the bottom of the working chamber.

Container is fitted with locking clamps and isolating it from the atmosphere.

Vacuum Arc Remelting Installation MRF ABJ 900 - ensemble sketches

2. Hearth Plate

Hearth Plate (working) of  installation is made of laminated copper, high purity, which presents a series of cavities (alveoli) of different sizes, depending on needs, being assembled into a whole with plate bottom, between the two plates being conducted a continuous stream of water for cooling.

 

The dimensions of hearth plate are 230 mm (diameter) x 13 mm (thickness) nominal thick, with the possibility of securing various configurations. At this time Vacuum Arc Remelting Installation is configured with seven (7) hearth plates, manufactured in accordance with the requirements of processed metallic materials.

 

3. Power Supply

 

Miller electric generator provides current to melt metallic charge, current intensity of 400...500 A.

Melting power is minimum 55 kVA, and the amperage of melting is minimum 650 A @ 60% DS, three-phase voltage.

4. Electrode stinger

 

Working electrode is made of  thoriated tungsten, easily replaceable with a diameter of 6.5 mm, powered by an electric cable water cooled. The copper water-cooled stinger (cathode) is sealed and insulated electrically for operator protection.

 

Non-consumable electrode (¼'' dia. x 3.00'' long) is centrally mounted on a moving ball joint and allows stinger both linear and radial movements so that it can cover the entire surface of the hearth plate. Ball joint allows the stinger to move easily around the furnace chamber.

 

Protective bellows covering electrode to prevent electrical shock hazard during operation allows the pressure level necessary to create appropriate handling of the electrode. 

Vacuum pump, functional scheme

The copper hearth plate for RAV MRF ABJ 900 installation

5. Vacuum System

 

Advanced vacuum system is composed of a preliminary vacuum pump and a diffusion pump Edwards can provide a level of 10-4...10-5 mbar vacuum.

Exhaust (air and argon) of the work chamber is done in steps, first with preliminary vacuum pump and then pump diffusion.

6. Inert Gas System

 

This furnace has been designed to operate in vacuum, argon, nitrogen, or any non-flammable gas.

Gas System in combination with the Vacuum System, provides a quick way to remove all the oxygen from the furnace chamber.

Alimentarea cu gaz inert – argon de puritate 4,8...5,0 se face de la o butelie prevãzutã cu manometre pentru mãsurarea presiunii si a debitelor, prin intermediul unor furtunuri flexibile. Presiunea pozitivã standard de lucru este de 0,14 kg/cm², cuptorul fiind dotat cu supapã de mentinere.

7. Water Cooling System

 

Different parts of the furnace, including furnace chamber, power cords, hearth plate of the furnace, etc. They are consuming cooling water.

 

The System Cooling Water provides supply to all vital components of the installation and is done through a pump with a capacity of 8 m³ with softened water network at 3 bar pressure inlet, and outlet pressure of 0.5 bar (differential pressure of 2.5 bar for optimum cooling).

 

Water supply and water exhaust manifold are fitted with water filters. To interrupt power supply in case of interruption of water is provided a water flow switch.

 

8. Oxygen Analyzer

 

Oxygen Analyzer determines the oxygen content inside the installation in a field of measurement of 0 ... 10,000 ppm.

9. Additional load

 

Additional load mechanism during melting, located at the bottom of the work chamber, in side place, allows entering during melting and refining at the appropriate time, additional quantities of alloys, without loss of pressure in the system.

Performances of MRF ABJ 900 installation
 

  • Maximum attainable temperature of arc is 3700ºC

  • Operating pressure: 0.14 kg / cm² (2 PSI)

  • Maximum vacuum 10-6 mbar

  • Outer shell temperature: less than 50 °C

  • Vacuum Arc Remelting Installation MRF ABJ 900 enables melting metals with high melting points such as Mo, Zr, W, Co, Ni, etc., thus creating the possibility of obtaining various alloys.

  • Excepted from making, alloys containing metals with low vaporization temperature, as Mg and Zn.

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