JPS641526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat treating a long metal material, and more particularly, the present invention relates to a method for heat treatment of a long metal material, and more particularly, the present invention relates to a method for heat treating a long metal material. The present invention relates to a method of heat-treating the entire length of the metal material by sequentially passing the metal material through the metal material. Here, if necessary, blast cooling or water cooling may be applied in front of the heating zone in the direction of material progress.
The present invention can also be applied to a case where a cooling zone composed of a mist cooling means is provided and a material heated in the heating zone is subjected to heat treatment in which the material is cooled in the cooling zone.

Therefore, in the above-mentioned heat treatment method, the heating zone is heated by induction because it can raise the temperature to the required temperature in a short time, the working environment is clean, and temperature adjustment is easy. It usually consists of a heating coil. In this case, a reasonable operation would be to energize the coil when the leading end of the metal material approaches the coil, and when the rear end of the metal material passes through the coil,
Preferably, power supply to the coil is stopped. In addition, in cases where a cooling zone is provided in front of the heating zone, when the tip of the metal material approaches the cooling zone, blast air, cooling water, mist, etc. are started to be sprayed toward the metal material. These injections must be stopped once the trailing end of the metal material has passed through the cooling zone. In addition, the above-mentioned induction heating coil has a plurality of coils in order to easily adjust the heating rate, or to divide the heating zone into one heating zone due to the difficulty of soaking the temperature in induction heating. It may consist of
In such a case, it is necessary to energize the coils and stop the power supply to each coil in a timely manner. It becomes impossible to accurately supply or stop power to such a coil, no matter how skilled the operator is.

The following methods can be used to control the supply or stop of power to the coil. That is, (a) Operator operates by visual inspection. (b) Detect the leading and trailing ends of the metal material with a limit switch or phototube, and automatically control the feed length by detecting the rotation speed of the roller that is in contact with the material. (c) Instead of detecting the rotation speed of the roller, a timer may be used. However, in the case of (a) above, there will be variations in the work, and additional labor will be required. In case (b), a detection error occurs due to slippage between the metal material and the roller. In the case of (c), each had its own drawbacks, such as the inability to change the feed rate of the metal material.

The present invention eliminates the above-mentioned drawbacks and provides a heat treatment method that can automatically supply or stop the power supply to each of the coils and start or stop the cooling operation in the cooling zone in a timely manner. and further provides a heat treatment method that makes it possible to supply different electric power along the length of a metal material according to a predetermined program and to adjust the cooling conditions by adjusting the material conveyance speed. It is something to do.

In the following, the invention will be explained in detail with reference to the figures.

Fig. 1 is a block diagram showing a heat treatment apparatus to which the method of the present invention is applied, and Figs. 2 a to d are process diagrams for hardening metal materials. During the insertion, c shows the process just before the rear end of the material reaches the heat treatment equipment, and d shows the process immediately after the material has been quenched.
d is a process diagram for tempering the material, a is just before the material reaches the heat treatment equipment, b is in the middle of tempering, c is just before the tip of the material reaches the heat treatment equipment, and d is the tempering of the material. This shows the process immediately after completion. In the figure 1a, 1b, 1c, 1
d and 1e are induction heating coils, and a heating zone 2 is formed by these coils. 3 is a cooling device, and a cooling zone 4 is formed by this device. 5 is a metal material to be heat treated. These are well known, and the material 5 is sent in the direction of arrow A during hardening, and is sent in the opposite direction to arrow A during tempering. 6 and 7 are carts, which are configured to move on tracks. These carts 6 and 7 are each equipped with dummy tubes 8 and 9 having a length L2 slightly larger than the length L1 of the heat treatment device, and move on the track with the material 5 sandwiched between these dummy tubes 8 and 9. As a result, the material 5 is fed. For example, when moving the material in the direction of arrow A, by driving the cart 6 and braking the cart 7, the material 5 is transferred to the dummy tube 8,
9 and is moved in the direction of arrow A. As mentioned above, it is known from Japanese Patent Application No. 52-12064 that the material 5 is moved using the carts 6 and 7 and the material is subjected to heat treatment over its entire length. ), therefore, the pulse generators 10 and 11 provided on the wheels of the carts 6 and 7 take out one pulse per rotation and count this pulse to generate the material 5. The moving distance can be calculated accurately. Even if the ground line on the trajectory is inclined, the slip does not occur, so the moving distance of the material 5 can still be calculated accurately. Reference numerals 12, 13, 14, and 15 indicate truck position detection devices such as limit switches or phototubes, which detect when the carts 6 and 7 pass in front of the detection devices 12-15. One of the detection devices
2 and 14 detect when the trolleys 6 and 7 move in the direction of arrow A and pass, respectively, and 13 and 1
5 detects when the carts 6 and 7 move in the direction opposite to the arrow A and pass. Sign P _Q
is determined as a reference point before the leading edge (right end) 5a of the material enters the heating and cooling zones 2 and 4 when the material 5 is fed in the direction of arrow A, and the material is When the tip 5a of the detector 5 reaches PQ, the trolley 7 passes in front of the detector 14 and turns it on. In addition, PQ is defined as a reference point before the rear end (left end) 5b of the material enters the heating and cooling zones 2 and 4 when the material 5 is fed in the direction of arrow A. (Fig. 2b), and the rear end 5b of the material 5
When PQ is reached (FIG. 2c), the trolley 6 passes in front of the detection device 12 and turns it on.

When PT sends material 5 in the opposite direction of arrow A,
Tip (left end) 5b or rear end (right end) 5 of material 5
a is defined as the reference point before entering the heating and cooling zones 2 and 4, and the tip (left end) 5 of the material 5
When b reaches PT (Fig. 3 a), trolley 6
The detection device 13 also detects the rear end 5a of the material 5.
When reaching PT (FIG. 3c), it is determined by the trolley 7 that the detection devices 15 are respectively turned on. P ₁ is the leftmost point of coil 1a, P ₂ is the midpoint between coils 1a and 1b, P ₃ is the midpoint between coils 1b and 1c, P ₄ is the midpoint between coils 1c and 1d, and P ₅ is the midpoint between coils 1c and 1d. The midpoint between coils 1d and 1e, P ₆ is the right end of coil 1e, P ₇ is the left end of cooling zone 4, and P ₈ is the right end of cooling zone.

Next, the operation of the above device will be explained. First, in the case of hardening treatment, the material 5 is sent in the direction of arrow A with the cart 6 in a driving state and the cart 7 in a braking state.
In this case, feeding of the material 5 is started from a state where the right end 5a of the material 5 is on the left side of _PQ . As a result of this feeding, the carriage 7 moves to the detection device 1 as shown in FIG. 2a.
When it reaches the front of the material 4, it is turned on and it is detected that the tip 5a of the material 5 has come to _PQ . Above P _Q and
Since the distance to P ₁ , P ₂ , P ₃ , ... P ₈ is preset, the pulses from the pulse generator 11 of the trolley 7 are counted based on the above detection, and the distance is determined according to the above distance. The number of pulses is counted. When this count number reaches a number corresponding to the distance from P _Q to _{P 1} , that is, when the right end 5a of the material 5 reaches P1, the power to the coil 1a is turned on and the count number reaches the distance from P _Q to P ₂ . When the number corresponds to , the power to the coil 1b is turned on. Similarly, turn on coils 1c, 1d, and 1e.
Activate the cooling device 3 by counting the distance P _Q to P ₇ . In this state, the material 5 is sent in the direction of arrow A to continue hardening. Near the end of the quenching process, the cart 6 reaches the front of the detection device 12 and turns it on, and when it is detected that the rear end 5b of the material 5 has reached PQ, the pulse generator 10 of the cart 6 pulses are counted based on the above detection. When this count counts the distance from P _Q to _{P 2} , that is, when the rear end 5b of the material 5 reaches P ₂ , the power to the coil 1a is turned off, and when the distance from P _Q to _{P 3} is counted, the power to the coil 1b is turned off. is turned off. Similarly, when the coils 1c, 1d, and 1e are powered off and the distance from _PQ to _P8 is counted, the cooling device 3 is also stopped.

In the case of tempering treatment, drive the trolley 7, drive the trolley 6
is braked to feed the material 5 in the direction opposite to the arrow A, but in this case, feeding of the material 5 is started from a state where the left end 5b of the material 5 is on the right side of P _T. By this feeding, the position of the tip 5b of the material 5 is detected by the cart 6, and when the tip comes to the right side of each coil 1a to 1e, the power of that coil is turned on, and the cart 6 detects the position of the tip 5b of the material 5.
Detect the position of the rear end 5a of the material 5, and when the rear end 5a comes to the left side of each coil 1a to 1e,
Turn off the power to that coil. The turning on and off of the power to the coils 1a to 1e during tempering is substantially the same as that during hardening, so a detailed explanation will be omitted.

In the above embodiment, the reference point at the leading end of the material 5 before entering the heating and cooling zones 2 and 4 and that at the rear end are the same points P _Q and P _T , but the reference point at the leading end and that at the rear end are the same. may be determined separately.

As described above, according to the present invention, it is not only possible to automatically turn on and off the coil power and operate the cooling device in a timely manner, but also to perform any heat treatment on any part of the metal material in the length direction. For example, material 5
When heat-treating the coil by passing it through the coil at a constant speed, the temperature at the leading and trailing ends tends to rise insufficiently and result in insufficient heating. The conveying speed of the coil can be slowed down, or the power supplied to the coil only to that part can be increased. The present invention goes one step further by providing a program control function to the coil power supply, cooling device, and truck drive device, and controlling the coil power output, frequency, refrigerant discharge amount of the cooling device, discharge pressure, and quenching, depending on the position of the material. It is also possible to automatically change the tempering feed rate according to a predetermined program. If heat treatment is performed using such a device, (a) the heating device, cooling device, and material feeding device, which are divided into several parts, can be automatically turned on, turned off, and controlled according to a predetermined program according to the position of the material; Therefore, the timing and setting of on/off and control can be performed with high precision in the length direction of the material and unattended. (b) Furthermore, uneven heating and cooling in the longitudinal direction of the material, particularly at the leading and trailing ends, can be greatly reduced, making it possible to heat treat with uniform quality over the entire length. (c) Since control is performed by detecting the leading and trailing ends of the material, the length of the material may be irregular.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a heat treatment apparatus showing an embodiment of the present invention, and Figs. 2 a to d are process diagrams for hardening metal materials, where a is just before the material reaches the heat treatment apparatus, and b is During quenching, c indicates the process immediately before the rear end of the material reaches the heat treatment equipment, and d indicates the process immediately after the material has been quenched.
is a process diagram for tempering the material, where a shows the material just before it reaches the heat treatment equipment, b shows the material in the middle of tempering,
c is just before the tip of the material reaches the heat treatment equipment, d
indicates the process immediately after the tempering of the material is completed.

Claims (1)

[Scope of Claims] 1. A long metal material is held between carts arranged at the outlet and inlet sides of the heat treatment apparatus through a dummy tube that is longer than the length of the heat treatment apparatus, and the material is
In the heat treatment method for a long metal material, the material is transferred to the heat treatment apparatus consisting of one or more induction heating coils and sequentially passed through the material to heat treat the entire length of the material, wherein one of the trolleys is configured to: The tip position of the material at any given time is detected based on the signal when passing through a cart position detection device installed along the trajectory, and the distance detection device provided on the cart detects the position of the tip of the material at any time as the material is transferred. The material transfer position is detected, and based on the signal when the other cart passes the cart position detection device installed along its track,
Detecting the rear end position of the material at any given time, and detecting the material transfer position with a distance detection device provided on the other truck as the material is transferred, and configuring the heat treatment apparatus based on these detected positions. A long metal material characterized by performing one or more of the following: controlling the power on/off of the induction heating coil, changing the power supplied to the coil, or changing the conveyance speed of the trolley. heat treatment method.