Sintering furnace

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Sintering Furnace Sintering Furnace

Transcript of Sintering furnace

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Sintering FurnaceSintering Furnace

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Introduction SinteringSintering

““The thermal treatment of a powder or The thermal treatment of a powder or compact at a temperature below the melting compact at a temperature below the melting point of the main constituent, for the purpose point of the main constituent, for the purpose of increasing its strength by bonding together of increasing its strength by bonding together of the particles.”of the particles.”

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1.1. Solid state sinteringSolid state sinteringOnly solid phases are present at the Only solid phases are present at the

sinter temperature.sinter temperature.

2.2. Liquid phase sinteringLiquid phase sinteringSmall amounts of liquid phase are Small amounts of liquid phase are

present during sintering.present during sintering.

3.3. Reactive sinteringReactive sinteringParticles react with each other to Particles react with each other to

new new product phases.product phases.

Types of SinteringTypes of Sintering

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What Happens During Sintering?What Happens During Sintering?

Diffusion occurs in any material above Diffusion occurs in any material above absolute zero, but it occurs much faster at absolute zero, but it occurs much faster at higher temperatures.higher temperatures.

The powdered material is held in a mold The powdered material is held in a mold and then heated to a temperature below and then heated to a temperature below the melting point.the melting point.

The atoms in the powder particles diffuse The atoms in the powder particles diffuse across the boundaries of the particles, across the boundaries of the particles, fusing the particles together and creating fusing the particles together and creating one solid piece. one solid piece.

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Sintering Furnace:Sintering Furnace:

“ “Sintering furnaces consist of Sintering furnaces consist of muffle to help direct, control and reduce muffle to help direct, control and reduce atmosphere flow.”atmosphere flow.”

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Features Of Sintering FurnaceFeatures Of Sintering Furnace• The sintering furnace can either be The sintering furnace can either be

heated with gas or electricity. heated with gas or electricity.

• Graphite rigid board insulation. Graphite Graphite rigid board insulation. Graphite heating elements on all four sides for heating elements on all four sides for optimum temperature uniformity.optimum temperature uniformity.

Monitoring of temperature atmosphere Monitoring of temperature atmosphere flow, dew point, oxygen content, carbon flow, dew point, oxygen content, carbon control, belt speed etc. is monitored and control, belt speed etc. is monitored and controlled automatically. controlled automatically.

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Temperature RangeTemperature Range• Maximum temperature: 2400Maximum temperature: 2400oo C . C .

Operating VoltageOperating Voltage480 volts, 3 phase, 225 kilowatts480 volts, 3 phase, 225 kilowatts

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Constituents of Sintering ChamberConstituents of Sintering Chamber& & ProcessProcess

Furnace ChambersFurnace Chambers

There are different types of chambers in the There are different types of chambers in the sintering furnace like,sintering furnace like,

1.1. Load/Unload ChamberLoad/Unload Chamber2.2. Controlled Oxidation Chamber Controlled Oxidation Chamber 3.3. Hot Zone ChamberHot Zone Chamber4.4. Rapid Cooling ChamberRapid Cooling Chamber5.5. Work Transfer Chamber. Work Transfer Chamber.

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Sintering Furnace:Sintering Furnace:

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The chambers can be opened at any time The chambers can be opened at any time for easy loading.for easy loading.

1.Load/Unload chamber1.Load/Unload chamber This chamber is used for loading and This chamber is used for loading and

unloading feed and product (sinter) unloading feed and product (sinter) respectively with the help of mesh belt. respectively with the help of mesh belt. The feed through this chamber goes to The feed through this chamber goes to oxidation chamber.oxidation chamber.

2.Controlled Oxidation Chamber:2.Controlled Oxidation Chamber: This chamber ensures the inert work This chamber ensures the inert work

transfer conditions and oxidation free transfer conditions and oxidation free environment for maximum hot zone life.environment for maximum hot zone life.

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3.Hot Zone Chamber:3.Hot Zone Chamber: The hot Zone Chamber is the The hot Zone Chamber is the

important part of the furnace which is important part of the furnace which is made up of Tungsten, Tantalum, Graphite, made up of Tungsten, Tantalum, Graphite, Molybdenum or high temperature Molybdenum or high temperature ceramics. ceramics.

Heating elements and shields can be Heating elements and shields can be designed with different sheath thicknesses designed with different sheath thicknesses and rigidized , temperature stabilized and rigidized , temperature stabilized materials to maximize life expectancy. The materials to maximize life expectancy. The heated element is then sent to the cooling heated element is then sent to the cooling chamber.chamber.

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4.Cooling chamber /Cooling System4.Cooling chamber /Cooling System

The furnace components are cooled The furnace components are cooled through the cooling system. The water through the cooling system. The water circuit is equipped with a flow switch and circuit is equipped with a flow switch and shut-off valve. shut-off valve.

Each water circuit drains into an open Each water circuit drains into an open drain bosh which consist of an optical eye drain bosh which consist of an optical eye to detect water flow. The heat exchanger to detect water flow. The heat exchanger is provided for rapid cooling. is provided for rapid cooling.

The cooling chamber through heat The cooling chamber through heat exchanger cools the materials within a exchanger cools the materials within a short span of time. short span of time.

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5.work transfer chamber5.work transfer chamber

This chamber ensures an inert work transfer. This chamber ensures an inert work transfer. The work transfer chamber contains the The work transfer chamber contains the mechanism for raising, lowering and moving mechanism for raising, lowering and moving the work stacks in transit from station to the work stacks in transit from station to station. station.

Power Supply and Control System Power Supply and Control System Power is supplied by Power is supplied by

high powered generator where is monitoringhigh powered generator where is monitoring is done effectively through field devices, is done effectively through field devices,

computers and programmable logic controller. computers and programmable logic controller.

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High Vacuum SystemHigh Vacuum System High vacuum system is High vacuum system is

designed to handle the high load of the designed to handle the high load of the gas. gas.

The system consist of diffusion pump, The system consist of diffusion pump, electro-pneumatic vacuum gate, valves electro-pneumatic vacuum gate, valves with limit switches, cold trap with with limit switches, cold trap with refrigeration condensing unit, mechanical refrigeration condensing unit, mechanical pump or dry pump with blower etc.pump or dry pump with blower etc.

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Post Sintering OperationsPost Sintering Operations If we do not get our required product after If we do not get our required product after

sintering process then we apply the post sintering process then we apply the post sintering operations. For this purpose we sintering operations. For this purpose we often apply some metallurgical processes often apply some metallurgical processes that help in binding the particles together.that help in binding the particles together.

Some post sintering techniques are,Some post sintering techniques are,1)Re-Pressing1)Re-Pressing2) Hot Re-Press2) Hot Re-Press3) Hot Isostatic Pressing3) Hot Isostatic Pressing4) Forging4) Forging5) Infiltration5) Infiltration6) Heat treatment 6) Heat treatment

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ApplicationsApplicationsThe applications of sintering furnace are The applications of sintering furnace are as follows:as follows:

Sintering of metal alloys Sintering of metal alloys Sintering of steels Sintering of steels Sintering of metallic powders Sintering of metallic powders Annealing Annealing BrazingBrazing

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