SU703738A1 - Furnace for chemical and thermal treatment - Google Patents

Description

(54) FURNACE FOR CHEMICAL-THERMAL PROCESSING

 one ; The invention relates to the field of chemical heat treatment / namely, continuous furnaces with zones separated by the composition of the saturating atmosphere; it can be used in the implementation of gas cementation and carbonitrization of metals. A conventional furnace for continuous gas carburizing, containing heating zones, diffusion saturation and diffusion extracts, each of which has gas from a controlled atmosphere, and heating and diffusion extracting zones are equipped with devices for producing a controlled atmosphere 1. The disadvantages of the known furnace are increased consumption of the controlled atmosphere (as compared with the known continuous-action furnaces with the zones separated by the composition of the controlled atmosphere) and the lack of precise th and stable, regulation of controlled carbon potential of the atmosphere in the soaking zone hydrochloric diffusion due to the fact that in this area enters the atmosphere with high carbon potential of diffusion saturation zone, which degrades the quality of processing. Also known is a furnace for chemical treatment, containing a chamber with gas inlets and gas intake elements connected in series through a gas blower cooler and a device for activating the controlled atmosphere 2. In this oven at any given time, the whole temperature and the same composition of the controlled atmosphere are at any time. The disadvantages of the known furnace are the increased consumption of the controlled atmosphere and the lack of possible and stable control of the carbon potential of the controlled atmosphere. The purpose of the invention is to improve the quality of processing and reduce the flow rate of the controlled atmosphere. The goal is achieved by placing gas inlets around the perimeter of the cross section of the chamber between the heating and diffusion saturation zones, and the gas intake elements between the diffusion saturation and diffusion exposure zones.

FIG. 1 schematically shows the proposed furnace; in fig. 2 is the same; the section along A-A in FIG. one. .

The lined chamber 1 of the furnace contains a heating zone B, a diffusion zone C, a saturation zone and a diffusion exposure zone D. The heating zone B and the diffusion holding zone D are supplied with gas. Water 2 controlled atmosphere. Between the heating zone B and diffusion saturation zone C there are additional, gas inlets 3 of the controlled atmosphere, and between zone C of the diffusionHot saturation and zone D of the diffusion outlet, gas intake elements 4. Additional gas inlets, 3 controlled atmospheres and gas intake elements 4 are connected to each other through successively connected rotary gas blower 5 and device b for activation of the controlled atmosphere, made in the form of a column filled with silica gel. Between the rotary gas blower 5 and the gas intake element 4 there is a refrigerator 7, and between the refrigerator 7 and the rotary gas blower 5 there are built-in nozzles 8 and 9 for connecting them respectively to sources of the controlled atmosphere and hydrocarbon gas. Additional gas inlets 3 of the controlled atmosphere and gas intake elements 4 are made in the form perforated pipes.

In the zone of heating and zone D diffu. Zion exposure is supplied to a controlled atmosphere with a carbon potential that corresponds to the optimum carbon content on the surface of the products being processed at a temperature of cooling which is achieved in zone D of diffusion exposure. The necessary reduction in the carbon potential of the controlled atmosphere, koTCipoe, is usually performed in order to reduce the flicker formation on cold products, due to the fact that, together with the products, oxygen is adsorbed on their surface into the heating zone B. The spent controlled atmosphere with a rotary blower 5 is collected at the end of the diffusion zone C through the gas intake elements 4, cooled in the refrigerator 7 and 33 devices 6 are directed for activation, thereby increasing the carbon potential of the controlled atmosphere. The activated controlled atmosphere through the additional gazvodov 3 controlled atmosphere serves at the beginning of the zone of diffusion saturation. As a result, a closed loop of the controlled atmosphere is created in the diffusion saturation zone. If necessary, for example, in order to create a positive pressure at the inlet of the rotary gas blower 5, through pipe 8 or Pipe 9 serves

Q is respectively either a controlled atmosphere or a hydrocarbon gas. Creating a closed loop of the longitudinal circulation of the controlled atmosphere with its intake. at the end of zone C of diffusion saturation and the supply of diffusion saturation at the beginning of this zone allows:

to exclude the entry of the atmosphere of zone B into the atmosphere into the atmosphere of zone C of diffusion saturation of the atmosphere and the atmosphere of the zone with diffusion saturation of at. the diffusion exposure zone D, and the exclusion of the atmosphere of the heating zone B in the atmosphere of the diffusion saturation zone C reduces the soot formation in the furnace, and

this improves the quality of processing and increases the durability of the furnace; reduce the flow of controlled atmosphere

0 exclude or minimize hydrocarbon gas additives.

Claims (1)

1. J. Electrotherms. M., № 95, p. 3-6. 2, Patent of Great Britain No. 1293053, cl. from 7 and 1972. / 7 ////// 7 ////// 1 Aa Figg