SU1199809A1 - Method of controlling process of chemical-heat treatment - Google Patents

Abstract

1. METHOD OF CONTROLING THE CHEMICAL-THERM TREATMENT PROCESS, including a constant supply of a controlled atmosphere to the furnace, feeding a component containing an alloying element into the furnace, measuring and regulating the potential of the alloying element of the furnace atmosphere by changing the component supplying the furnace containing an alloying element that, in order to improve the quality of chemical-thermal processing. In addition, the potentials of the alloying element entering the furnace and the atmosphere leaving the furnace are measured, the difference between the measured potentials is determined, the potential of the atmosphere entering the furnace is controlled as a function of the potential difference detected, for example, linearly and simultaneously the lower and upper limits of the potential entering the furnace atmosphere. 2. The method according to claim 1, which is also distinguished by the fact that the lower limit of the potential of the atmosphere entering the furnace is set to a given set point in the centering of the alloying element in the surface layer of the workpiece. 3. The method according to claim 1, characterized in that the upper limit of the potential of the atmosphere entering the furnace is set equal to the limiting solubility concentration of the alloying element of the CO element in the metal being treated from the product. C O O

Description

The invention relates to metallurgy, in particular to the chemical-thermal treatment of metal products in furnaces with controlled atmosphere, and specifically to the management of gas processes and the use of components with alloying elements such as C, N, S, etc.

The purpose of the invention is to improve the quality of chemical heat treatment.

The drawing shows a block diagram of a device for carrying out the proposed method.

In furnace 1, parts 2 are placed on pallets 3. A process gas consisting of endogas (main carrier gas) and methane (source of carbon dopant) is supplied to the furnace. At the entrance and exit of the furnace, sensors 4 and 5 are installed to determine the C-potential, for example, sensors for determining the trace oxygen concentration, representing electrochemical cells of solid electrolyte, sensors 6 and 7 of carbon monoxide, sensors 8 and 9 of temperature. The sensor outputs are connected to the inputs of the counting devices 10 and 11 for calculating the current value of the C-potential. The first outputs of the computing devices 10 and 11 are connected to the input of the comparison device 12, the output of which is connected to the input of the correction device 13, which is connected in series with the key 14, the setpoint 15 of the current C-potential value, the comparison device 16, the regulator 17, the actuator - 18 and the regulatory authority 19 on the methane supply line to the furnace.

The second output of the device 10 is connected to the first input of the comparison device 20, to the second input of which the unit 21 of the C-potential limit values is connected.

The output of the comparison device 20 is connected to the second input of the key 14. The third output of the device 10 is connected to the second input of the comparison device 16.

The operation of the device is as follows.

If the current value of the atmospheric C-potential entering furnace 1 deviates from the value set on the setting unit 15, the controller 17 by means of an actuator 18

and regulator 19 alters the consumption of methane and eliminates the deviation of the C-potential from the task. The value of the atmospheric C-potential at the preset 15 is adjusted by means of the device 13, which generates a corrective action in accordance with the determined value of the difference of the C-potentials of the incoming and outgoing furnace atmosphere. With an increase in the C-potential difference, the magnitude of the corrective action with a key, 14 increases and, thus, the value of the C-potential in the furnace increases.

5 Corrective action may be effected, for example, by a linear law.

The key 14 connects the correction device 13 with the setting device 15 to

0 as long as the potential of the incoming atmosphere reaches the limit values specified.

When the potential of the incoming atmosphere exceeds the limit values, the comparison device 20 generates a signal that switches off the correction device 13 from the setter 15 with the help of a key 17, and the correctional influence is terminated.

Thus, on the proposed

In the method, the predetermined value of the potential of the diruki element is automatically corrected in accordance with the quantity of the moment arriving.

g alloying element in the workpiece, i.e. taking into account the current situation in the furnace, which allows to obtain a more accurate distribution of the alloying element in the surface layer of the product.

Outgoing to3

Claims (3)

'1. METHOD FOR CONTROLLING A CHEMICAL AND THERMAL PROCESSING PROCESS, comprising continuously supplying a controlled atmosphere to the furnace, feeding a component containing an alloying element to the furnace, measuring and controlling the potential of the alloying element of the furnace atmosphere by changing the supply to the furnace of a component containing an alloying element, characterized in that, c In order to improve the quality of chemical-thermal treatment, the potentials of the alloying element entering the furnace and leaving the furnace are additionally measured, the difference is measured potentials, the potential is adjusted in the furnace entering the atmosphere as a function of the potential difference is determined, for example, linearly and simultaneously restrict the lower and upper limits of the capacity included in the furnace atmosphere. 2. The method of pop. ^ characterized in that the lower limit of the potential of the atmosphere entering the furnace is set equal to a given concentration of the alloying element in the surface layer of the workpiece. 3. The method of pop. 1, characterized in that the upper limit of the potential of the atmosphere entering the furnace is set equal to the limiting concentration of solubility of the alloying element in the metal of the workpiece.