A horizontal high-pressure gas quenching-tempering-nitridation vacuum multipurpose furnace

Abstract

The invention discloses a horizontal high-pressure gas quenching-tempering-nitridation vacuum multipurpose furnace and relates to the field of metal vacuum thermal treatment. The furnace comprises a vacuum furnace main body, a heating chamber, a wind cooling system, a vacuum unit, a gas supplying system and an electric control system. The heating chamber comprises heating elements, a cylinder, a front cover and a back cover. The front cover and the back cover are provided with wind guiding holes. An air cylinder drives movable doors to open and close the wind guiding holes so as to guarantee circular flowing of cooling gas during tempering and gas quenching and to guarantee a closed structure of the heating chamber during nitridation. The furnace overcomes the disadvantages caused by adoption of metal nitridation tanks adopted by nitridation furnaces at present, namely slow heating and cooling speeds, low atmosphere pressure, and the like. The furnace is provided with using conditions for high-pressure high-flow-rate quenching and tempering, is simple in structure and practical, and truly achieves the using requirements on vacuum multipurpose furnaces.

Description

technical field [0001] The invention relates to the field of vacuum furnaces, in particular to a horizontal high-pressure gas quenching, tempering and nitriding vacuum furnace. Background technique [0002] At present, the external heating gas nitriding furnace used in China has the following disadvantages: (1) The heat energy consumption is large: the parts that need to be nitrided are placed in the nitriding tank made of heat-resistant steel, heated in the pit furnace, and the nitriding tank As light as one or two hundred kilograms, as heavy as five or six hundred kilograms, or even heavier, the heat energy consumption is very large. (2) Slow cooling: due to indirect heating, the temperature of nitriding parts is slow to rise, and the temperature is also slow. In order to increase the cooling speed, some put the furnace tank out for air cooling, and some add an air cooling system on the furnace body, but the cooling is still very slow. (3) Low pressure of nitriding atmos...

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Problems solved by technology

[0002] At present, the external heating gas nitriding furnace used in China has the following disadvantages: (1) The heat energy consumption is large: the parts that need to be nitrided are placed in the nitriding tank made of heat-resistant steel, heated in the pit furnace, and the nitriding tank As light as one or two hundred kilograms, as heavy as five or six hundred kilograms, or even heavier, it consumes a lot of heat energy

In order to increase the cooling speed, some put the furnace tank out for air cooling, and some add an air cooling system on the furnace body, but the cooling is still very slow.

(3) Low pressure of nitriding atmosphere: The pressure of nitriding atmosphere in the tank is low, usually only tens of millimeters of oil column, the atmosphere pressure is not high, which greatly affects the speed and quality of nitriding

(4) The air intake structure is unreasonable: most furnaces insert a vent pipe from the top of the nitriding tank to the bottom of the tank, and the ammonia gas flows from the bottom of the tank to the inside of the tank, and is discharged from the gas outlet

Therefore, this vent structure is not ideal

(5) Not conducive to diffusion: In order to eliminate the brittle phase layer (white layer) on the surface of the nitriding layer, the diffusion process under the condition of high decomposition rate is adopted. However, at the nitriding temperature, it is difficult to achieve no active nitrogen atoms in the atmosphere The presence, therefore, is detrimental to the diffusion process

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