RU2235144C2 - Thermochemical treatment process - Google Patents

Abstract

FIELD: machine engineering, namely thermochemical treatment of parts, blanks and tools.

SUBSTANCE: process comprises steps of heating furnace; loading solid disintegrated material in furnace; blowing through said material gas-air mixture and placing treated part in furnace; at treatment process increasing by 2 - 4 times air density in gas-air mixture; at periods of blowing through solid disintegrated material gas-air mixture with increased air density ceasing process of heating furnace.

EFFECT: lowered consumption of electric energy and gases contained in gas-air mixture, improved ecological safety.

Description

The invention relates to the field of chemical-thermal processing of workpieces, parts and tools, can be used in mechanical engineering.

The known method of chemical-thermal treatment described in the article: Bobok A.N., Shavelkin A.D., Pavlova A.V., Bark V.M., Karpovskaya S.L. Economic efficiency and adaptation to market conditions and demand for manufactured products when applying universal environmentally friendly technology and equipment and technical maintenance in the fluidized bed of a special catalyst // Izvestia Tulsk. state un-that. - Ser. "Materials Science". - Issue 1. - 2000. - P.184-197, in which a solid crushed substance is placed in the furnace, the gas-air mixture is blown through it, the furnace is heated, the workpieces are placed in the furnace and the furnace with parts is heated and the gas-air mixture is blown throughout the processing of the parts.

However, this method involves a high consumption of gases used in the gas-air mixture and a high consumption of electric energy, since this method does not provide for the possibility of increasing the composition of the air-gas mixture of air and changing the heating mode of the furnace as the hardened layer saturates on the surface of the workpiece. The high consumption of gases and electric energy increases the negative environmental burden.

Closest to the proposed is the method of chemical-thermal treatment described in the patent of the Russian Federation No. 2132403 "Method of chemical-thermal treatment", 6 C 23 C 8/00, 10/00, publ. 06/27/99, bull. No. 18, in which a solid crushed substance is placed in the furnace, the gas-air mixture is blown through it, the furnace is heated, the workpieces are placed in the furnace and the furnace with the parts is heated and the gas-air mixture is blown throughout the processing of the parts.

However, this method involves a high consumption of gases used in the gas-air mixture and a high consumption of electric energy, since this method does not provide for the possibility of increasing the composition of the air-gas mixture of air and changing the heating mode of the furnace as the hardened layer saturates on the surface of the workpiece. The high consumption of gases and electric energy increases the negative environmental burden.

The proposed method of chemical-thermal treatment is characterized by the following features: placing in the furnace solid crushed substance, heating the furnace, blowing the gas-air mixture through it, placing the workpiece in the furnace, characterized in that during processing the part in the gas-air mixture is periodically increased by 2-4 times the specific gravity of air and during periods of blowing solid ground matter with a gas-air mixture with an increased specific gravity of air, the furnace ceases to be heated, while placing in the furnace a solid crushed substance, blowing through it a gas-air mixture and placing the workpiece in the furnace after heating the furnace.

EFFECT: reduced consumption of gases used in a gas-air mixture by periodically reducing by 2-4 times their specific gravity in a gas-air mixture after saturation of the surface layers of the workpiece with impurities from the gas-air mixture for a period of time necessary for their redistribution into the surface of the workpiece; reduction of energy consumption due to the termination of heating of the furnace during periods of blowing the gas-air mixture with an increased specific gravity of air and placing solid ground matter in the furnace, blowing the gas-air mixture through it and placing the workpiece in the furnace after heating the furnace; improving environmental safety by reducing the discharge of gases and heat into the atmosphere.

The method is as follows.

The workpiece is placed in a heated furnace with a solid crushed substance (a special catalyst) through which the air-gas mixture is blown. The composition of the catalyst and gas-air mixture is selected depending on the type of chemical-thermal treatment, for example, using the materials given in the article: Bobok A.N., Shavelkin A.D., Pavlova A.V., Bark V.M., Karpovskaya S .L. Economic efficiency and adaptation to market conditions and demand for manufactured products when applying universal environmentally friendly technology and equipment and technical maintenance in the fluidized bed of a special catalyst // Izvestia Tulsk. state un-that. - Ser. "Materials Science". - Issue 1. - 2000. - S.184-197. The part is kept in the furnace under constant heating and blowing conditions of the gas-air mixture until the surface layers (0.01-0.05 mm) of the workpiece are saturated with the introduction of impurities from the gas-air mixture. Then, the air content in the gas-air mixture is increased by 2-4 times, the furnace is stopped heating by disconnecting its heating elements from the mains, and redistribution of interstitial impurities from the gas-air mixture from the surface layers deep into the surface of the workpiece is expected; in layers located further 0,01-0,05 mm from the surface of the part. Moreover, it should be noted that the rate of saturation of the surface layers of the workpiece with interstitial impurities significantly exceeds the rate of their redistribution to deeper layers. After the redistribution of interstitial impurities from the surface layers of the workpiece to deeper ones, the furnace heating and the composition of the gas-air mixture are restored. The part is kept in the furnace under constant heating and blowing of the gas-air mixture until the surface layers (0.01-0.05 mm) of the workpiece are saturated with penetration impurities from the gas-air mixture, and then the above operations are repeated. Periodic repeat operations continue until the specified depth of the processed layer of the surface of the part.

Claims (1)

The method of chemical-thermal treatment, including placing solid crushed material in the furnace, heating the furnace, blowing the gas-air mixture through the solid crushed substance, placing the workpiece in the furnace, characterized in that during the processing of the part in the gas-air mixture periodically increase by 2-4 times specific gravity of air and during periods of blowing solid ground matter with a gas-air mixture with an increased specific gravity of air, the furnace ceases to be heated, while the furnace a solid particulate substance therethrough insufflation gas mixture and placement in an oven is performed after the workpiece heating furnace.