This furnace represents an advanced solution for the heat treatment processes as it is suited to various materials to be treated and to many different types of charge and piece geometry.
The heating up of the charge may be applied either in high vacuum or with partial pressure of inert gas. This is made possible by an automatic system that regulates the vacuum within the range of 0,1 to 1 mbar at a preset level, introducing argon or nitrogen.
Quenching of the charge can be achieved either in middle vacuum or by gas flow.
The pressure can be preset between 0.8 to 1.0 bar and circulated by a centrifugal fan.
During the quenching phase it is possible to circulate the gas (nitrogen, argon, etc.) at a maximum pressure of 1.0 bar cooling the charge from above, from below, from top and bottom, alternately, or top and bottom together producing the fastest decrease of charge temperature with the best uniformity.
Size (WxHxL): 5x3x7 m
Hot zone (WxHxL): 800x800x1200 mm
Max temperature: 1400 °C
Charge: 500 kg
Final vacuum: 1E-5/1E-6 mbar
Operating vacuum: 1E-4/1E-5 mbar
Max cooling pressure: 1 bar
The construction materials, welding, vessel design together with all electrical wiring, connection and general pipework, etc. are in line with relevant Italian and European standards.
The work cycle is completely automatic and does not require the surveillance of manual operators.
The temperatures and pressures (partial gas and quenching gas) are programmed with high precision.
The geometrical configuration of the resistor and of the thermic chamber lead to uniformity of temperature.
The large flow capacity of the quenching gas circulation fan makes it possible to widen the range of the materials to be treated and the density of the charge. Therefore, cycles become shorter and the furnace can be used more intensively.
The vacuum pump down time is rapid due to the large dimension of the pumping group.
The furnace with its water cooled double wall does not irradiate heat and can be installed in air conditioned and thermostatically controlled room without any valuable change in room temperature.
The furnace absorbs electric power only when needed.
There is no environment pollution of the atmosphere or in the discharged water.
The vessel is composed of a carbon steel vessel, on a horizontal axis, cambered at both ends, cooled by a double wall jacket for circulation of cooling water and sealed with toric joints of a special elastomer suited to vacuum and high temperature. The tank has been designed to bear a pressure of 1. 0 bar, to support the charge and has been verified to stand up to high vacuum.
The front hatch turns on solid hinges and opens to allow loading and unloading of the charge and the inspection of the various components.
The geometry of the furnace is such that it is easy to have access to the thermic chamber and to inspect or operate with the various components inside the vacuum chamber.
The hot zone is built of a strong refractory steel structure that can support the heavy weight of the charge and the basket, the heating elements and the insulation, constructed in such a way that no permanent heat deformations are possible.
Inside the thermic chamber, panels of rigid graphite board offer a low mass thermic insulation to the hot zone and drastically reduce the loss of heat towards the outside.
The panels are fixed to the structure by molybdenum pins.
The rigid graphite of the insulating system is protected from the violent flow of the gas by a flexible 2 mm graphite foil, it has high wear resistance to the flow whilst allowing good desorption and permeability of the gas.
The thermic chamber rests on moveable supports that allow easy extraction of the unit for inspection and maintenance.
The quenching gas is channeled towards the charge over the heat exchanger and through the space between the walls of the thermic chamber and the vacuum vessel.
The heating system of this furnace is made up of heating elements at the top, bottom, sides and front and back providing 6 independent zones of the hot zone.
The resistor is composed of a series of graphite bars, connected to each other by connections of the same material and electrically fed by feedthroughs, vacuum sealed and water cooled.
The dimensions of the bars and their geometry allow an effective thermic exchange between the graphite bars and the charge, produced by radiation with a minimal difference of temperature between the resistor and the pieces.