RU2235145C2 - Thermochemical treatment process - Google Patents

Abstract

FIELD: thermochemical treatment of parts, blanks, tools, possibly in machine engineering.

SUBSTANCE: process comprises steps of placing solid disintegrated dielectric material into furnace; heating furnace; blowing through solid disintegrated material gas-air mixture; placing treated part in furnace; at treatment process applying electric voltage to part; performing treatment together with temperature cycling and cyclically lowering concentrations of working gases; placing solid disintegrated material in furnace and blowing through it gas-air mixture after heating furnace.

EFFECT: elimination of adsorption process, lowered consumption of electric energy and gases used in gas-air mixture, enhanced ecological safety.

1 ex

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. - S. 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 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 electrical energy, since this method does not provide for the possibility of creating electrical voltage on the surface of the workpiece, due to the polarity of the reverse charge of the ionized deposited (adsorbed) gas. 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 creating electrical voltage on the surface of the workpiece, due to the polarity of the reverse charge of the ionized deposited (adsorbed) gas. 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 a solid ground dielectric substance, heating the furnace, blowing the gas-air mixture through the solid ground substance, placing the workpiece in the furnace, and during the processing of the part, voltage is applied to the part, while the processing is carried out together with thermal cycling and cyclic depletion of the concentration of working gases, and the placement in the furnace of solid ground substance, blowing through it, the gas-air mixture and placement of the workpiece in the furnace is carried out after heating the furnace.

EFFECT: reduced consumption used in a gas-air mixture of gases by periodically reducing their specific gravity in a gas-air mixture of gases by creating an electrostatic or electrodynamic field around the workpiece, which, acting on the ionized working gas, directs it to the surface of the part, thereby increasing near-surface concentration, accelerates the adsorption process, which leads to a decrease in gas and electricity consumption, increased environmental safety due to reduced emission of gases and heat into the atmosphere.

The method is as follows.

A solid crushed dielectric substance (a special catalyst) is poured into a heated furnace, through which the air-gas mixture is blown, the workpiece is placed. The composition of the catalyst and the 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. A high voltage is applied to the workpiece, the part is held for the right time under given conditions, temperature, gas-air mixture flow rate and voltage. This treatment can be carried out in conjunction with thermal cycling and cyclic depletion of working gas concentrations. The operation is carried out until the specified depth of the processed layer of the surface of the part.

An example of a specific application.

The proposed method was implemented during the cementation of a part made of steel 20X in the installation of a fluidized bed “Corundum-300”. Certificate ROSS RU. ME 71. B00083.

A catalyst of the NAM grade was poured into a crucible of a furnace as a solid ground dielectric material to create a fluidized bed. An air-gas mixture consisting of 75% air and 25% propane-butane was fed through a gas distribution grill at the bottom of the crucible. The furnace was heated to 950 ° C. The part on the suspension of the ceramic insulator was placed in the working space of the furnace and, taking into account that the main working gas, carbon monoxide CO, has a positive valence, a negative pulse discharge of 65,000 V and a current of 2.8 mA were applied to the part. The positive pole of the power source is connected to the crucible of the furnace and is grounded.

The duration of the discharge was determined by the capacity of the capacitor bank. During the chemical-thermal operation, it was possible to reduce the consumption of the propane-butane mixture by 1.2 times and to reduce the energy consumption by about 2% without compromising the quality of heat treatment of the part in comparison with the application of the known method.

Claims (1)

A method of chemical-thermal treatment, which includes placing a solid ground dielectric substance in a furnace, heating the furnace, blowing a gas-air mixture through a solid ground substance, placing the workpiece in the furnace, and during the processing of the part, an electric voltage is applied to the part, the processing being carried out together with thermal cycling and cyclic depletion of the concentration of working gases, and the placement in the furnace of solid crushed substance, blowing through it a gas-air mixture and placed in the furnace, the workpiece is carried out after heating the furnace.