JPH06341774A - Temperature measuring method for induction heating element - Google Patents

Abstract

PURPOSE:To prevent invasion of the atmospheric pressure and steam to a periphery of an element to be heated and to accurately automatically control the element to be heated by maintaining the periphery of the element to be heated in an inert gas atmosphere in an apparatus for inserting the element to be heated into an induction coil to heat it. CONSTITUTION:An element 1 to be heated inserted into an induction coil 2 in which power is supplied and heated while rotating or moving. In this case, a power regulator 5 of the coil 2 connected to a temperature regulator 15 of the element 1 to be heated is operated to automatically control the temperature of the element 1 to be heated. Incidentally, a periphery of the element 1 to be heated is maintained in an inert gas atmosphere. That is, the periphery of the element 1 to be heated is covered with a chamber 8, and inert gas is injected from a nozzle into its interior. An atmospheric pressure of the gas is measured by a pressure measuring instrument 11, and a flow regulating valve 9 is so controlled by an inert gas flow regulator 12 that the pressure becomes a positive pressure as compared with the atmosphere. Thus, a temperature measurement and an automatic temperature control of the element 1 to be heated are accurately conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the surface temperature of an object to be heated in the induction heating of metal.

[0002]

2. Description of the Related Art In induction heating of metal, when the object to be heated is fixed, the temperature of the object to be heated can be accurately measured by a contact method using a thermocouple or the like. When heating or rotating an object to be heated as in the case of heating, non-contact temperature measurement is performed, and accurate temperature measurement is difficult. The reason is that when the object to be heated is heated to a high temperature, the metal surface is oxidized and the thermal emissivity changes, and in the case of quenching, the thermal radiation is absorbed by steam such as quenching water and the temperature measurement error increases. This is because there are drawbacks.

[0003]

The above-mentioned prior art does not consider the fact that the object to be heated is oxidized by oxygen in the atmosphere at a high temperature, and there is a problem in dealing with the change in the thermal emissivity due to the oxidation of the metal surface. there were. The change of the thermal emissivity depends on the chemical composition of the object to be heated, the heating temperature, the rotation and the moving speed,
It is difficult to accurately grasp certain conditions.

On the other hand, in an induction heating apparatus that also serves as quenching, water vapor or the like generated during quenching absorbs thermal radiation and causes an error in temperature measurement.

It is an object of the present invention to shut off the atmospheric atmosphere which changes the thermal emissivity of the object to be heated to prevent the invasion of the atmosphere and the ingress of water vapor and the like.

[0006]

In order to achieve the above object, one of the objects to be heated is injected with an inert gas while swirling, and an atmosphere of the object to be heated is made an inert gas atmosphere. Also,
In order to prevent the invasion of the atmosphere and the invasion of water vapor, it is possible to increase the flow rate of the inert gas to be injected, but if it becomes excessive, it will adversely affect the overheating temperature of the heated object, The inert gas atmosphere pressure is controlled to a constant positive pressure.

[0007]

[Function] In order to maintain an inert gas atmosphere around the object to be heated, the openings at both ends of the induction coil should be made small to reduce the outflow of the inert gas to be injected, and the pressure of the inert gas atmosphere should be detected. The atmospheric pressure and water vapor are prevented from entering by controlling the positive pressure from the atmosphere.

[0008]

1 is a block diagram of a temperature measuring method of an induction hardening apparatus according to an embodiment of the present invention. In FIG. 1, the object to be heated 1 is inserted into the induction coil 2, and the induction power adjusting device 5 supplies electric power to the induction coil 2 to heat the object to be heated 1. The object to be heated 1 is a device that is heated while rotating, descends, and discharges cooling water from the quenching cooling water discharge ring 6 to quench it.

The heated area of the object to be heated 1 is discharged from the inert gas discharge chamber 8 while swirling from the nozzle 16 shown in FIG.
Create an inert gas atmosphere. The atmosphere pressure of the inert gas is measured by the inert gas pressure measuring device 11, and the inert gas flow rate adjusting valve 12 is adjusted by the inert gas flow rate adjusting device 12 so that the inert gas atmosphere pressure becomes more positive than the atmospheric pressure. .

The temperature of the object 1 to be heated is detected by the emission temperature detection sensor 13 and converted into the temperature by the radiation temperature measuring device 14. The heated object temperature adjusting device 15 compares the preset quenching heating temperature with the temperature measured by the radiation temperature measuring device 14, and operates the induction power adjusting device 5 so as to reduce the deviation, thereby heating the heated object. The automatic temperature control of No. 1 is performed.

[0011]

According to the present invention, since the object to be heated is heated in an inert gas atmosphere, it is not oxidized even at a high temperature, and water vapor such as cooling water is prevented from entering during quenching. Since this can be prevented, highly accurate temperature measurement can be performed, which is effective for automatic temperature control of the object to be heated by the induction coil.

[Brief description of drawings]

FIG. 1 is a block diagram of a temperature measuring method of an induction hardening apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a nozzle of an inert gas discharge chamber of an induction hardening apparatus.

[Explanation of symbols]

1 ... Object to be heated, 2 ... Induction coil, 3 ... Insulating heat insulating material, 4
... Bus bar, 5 ... Induction power adjusting device, 6 ... Quenching water discharge ring, 7 ... Quenching water opening / closing valve, 8 ... Inert gas discharge chamber, 9 ... Inert gas flow control valve, 10 ... No Active gas pressure reducing valve, 11 ... Inert gas pressure measuring device, 12 ... Inert gas flow rate controller, 13 ... Radiation temperature measuring sensor, 14 ...
Radiation temperature measuring device, 15 ... Heated object temperature control device, 16 ...
Inert gas discharge nozzle.

Claims (2)

[Claims] 1. An induction heating object is inserted into an induction coil, and the induction heating object is rotated or moved to supply electric power to the induction coil to heat the induction heating object. A method for measuring the temperature of an object to be heated, characterized in that the surroundings of the are heated to an inert gas atmosphere. 2. The method for measuring the temperature of an induction heating object according to claim 1, wherein the flow rate of the inert gas is controlled when the periphery of the object to be heated is an inert gas atmosphere.