JPS5938046B2 - heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for handling a long pipe material such as a copper pipe while passing the pipe material between a heat source divided into a plurality of parts and a pinch roller installed between the heat sources. The present invention relates to a heat treatment apparatus that performs continuous heat treatment.

Hereinafter, a case where a long object such as a steel pipe is heat treated with an induction heating device will be explained as an example. When transporting the above-mentioned long objects with a gap between them in the longitudinal direction, or when transporting the long objects continuously with the ends of the objects in close contact with each other, a plurality of induction heating coils (hereinafter referred to as heating coils) are generally arranged. However, a pinch roller is usually placed between the heating coils in order to minimize deformation of the steel pipe during heat treatment and to ensure a stable transfer speed. For the purpose mentioned above, this pinch roller has multiple rollers arranged in the circumferential direction of the steel pipe in order to press the outer circumference of the steel pipe as uniformly as possible, and various improvements have been made to the shape of the rollers that contact the outer circumferential surface of the steel pipe. In addition, a drive source such as air or hydraulics is used in the direction perpendicular to the surface of the tube to move the pinch rollers at the end of the tube in and out, allowing them to move up and down. It is normal to have one. Figure 1 is a conceptual diagram of an example in which pinch rollers are arranged alternately with heating coils 2 in the transport direction of steel pipe 1, except for the air, hydraulic, etc. circuits described above. Roller 3 is upper and lower 2
The figure shows the case where the pinch roller 3 is divided into individual parts, and the bearing, support column, drive motor, etc. of the pinch roller 3 are omitted.

Such a pinch roller 3 generally moves backward until the end of the steel pipe 1 enters directly below the pinch roller 3 (
In FIG. 1, the lower pinch roller 3 is fixed and the upper pinch roller 3 is movable in the vertical direction. ), after the end of the steel pipe 1 enters, it moves forward (or descends) and comes into contact with the surface of the steel pipe 1 with a low pressing force. Here, the pressing force is made relatively low (in one example, when a 139.7φ x 7.72 steel pipe is heated to approximately 950°C, it is approximately 90 kg) due to the radial deformation of the heated steel pipe 1. This is to minimize the However, with such a low pressing force, during heating, the steel pipe 1 may lose residual stress that it had as a material from the previous process (for example, if the bend was straightened with a straightener before heat treatment, the residual stress may ), the thickness of the steel pipe 1 differs in the circumferential direction, so-called uneven thickness (this is especially common in seamless steel pipes).
In many cases, the steel pipe 1 itself is pushed by the bent and deformed steel pipe 1, and cannot resist it, retreating or rising. Coil 2 is a steel pipe 1 from the point of view of heating efficiency.
Since the distance between the heating coil 2 and the inner surface of the heating coil 2, that is, the gap, is relatively small (for example, 20 to 30 pilgrims), the tip of the steel pipe 1 may collide with the side of the opening, resulting in damage to the heating coil 2. . Furthermore, if the steel pipe 1 is in the center, the bent portion will come into contact with the inner surface of the heating coil 2, which may also cause damage. Therefore, as a method to have a bending suppressing effect, the pressing force must be increased to the extent that it has a suppressing effect (for example, in the case of quenching the above-mentioned pipe material, approximately 500 to 1,500 kg)
) and setting the position of the pinch roller 3 close to the pipe diameter. However, in this case, the unbent steel pipe passes through without being deformed in the radial direction, and the bending that occurs during heating can be suppressed, but it is transferred into the heat treatment equipment with a certain degree of bending already. The pinch roller acts like a stopper on the steel pipe that is about to pass through the pinch roller section, causing the transfer speed to stop or fluctuate. FIG. 2 shows a state in which the tip of the steel pipe 1 is bent and collides with the pinch rollers, causing the steel pipe 1 to stop. This invention was made in view of these points, and it is possible to reduce the bending of the heat-treated member during heating, and to heat-treat the heat-treated member without damaging the heating source even if the heat-treated member is bent before heat treatment. The present invention provides a heat treatment apparatus that can perform the following steps.

FIG. 1 is a diagram showing the principle of one embodiment.

1 is a steel pipe that is being transferred, 2 is a heating coil, and the figure shows a case where there are four.

Note that the induction heating power source and the like connected to the heating coil 2 are not directly related to this description, so they are all omitted. 3 is a pinch roller, which also has two upper and lower parts as mentioned above.
Only one roller is shown and the others are omitted.

In addition, here, the lower roller 3 is fixed, and the upper roller 3
The only movement is up and down. The operation is represented by the second pinch roller from the left in the figure. It is assumed that the other pinch rollers operate in a similar manner. If a normal steel pipe 1 with no bends is currently being transferred, the upper pinch roller 3 is pressing the surface of the steel pipe 1 with a pressing force PA.

This PA is the weight of the movable parts related to the air cylinder including the upper pinch roller 3. The force with which this movable part is lifted upward by the air cylinder 4 is P. It is expressed as the case.

Of course, this PA is a relatively low pressing force of 7 degrees, which does not impair the roundness of the heated steel pipe, as described above. Suppose now that a steel pipe is being transported, passes through a heating coil, becomes hot, and bends due to the reasons mentioned above. This bending pushes up the upper roller 3, but in this case as well, a constant low pressing force PA continues to push the upper roller 3 down until the gap marked G in the figure becomes zero. Therefore, while the upper roller 3 is rising by a distance G from the position where the steel pipe 1 is not bent, it is always pushing the steel pipe 1 downward with the pressure of PA. In the figure, the air cylinder 4 including the solenoid valve for the cylinder is shown operating in the above state. G
When the pressure reaches zero, the lower stopper 5 provided at the upper end of the rod penetrating the air cylinder 4 closes the upper stopper 7 provided at the lower end of the rod of the hydraulic cylinder 6 installed above the air cylinder 4. It comes into contact with the upper end of the inner surface. When the bending of the steel pipe 1 becomes even larger, the rod of the air cylinder 4 pushes up the rod of the hydraulic cylinder 6 via these upper and lower stoppers. In this state, the pressing force PB applied to the upper roller 3 is equal to the force P2 exerted by the hydraulic cylinder 6 pushing down the lower stopper 5 (this P2 is equal to the pressure P1 due to the oil pressure in the hydraulic cylinder 6). It is the sum of the rod-related weight W of the hydraulic cylinder 6.), and the pressing force is higher than PA. In the figure, the hydraulic solenoid valve 8 and the air solenoid valve 9 are both operating in a bending suppressed state. In this state, each solenoid valve is operating in a circuit with a pressure regulating valve, so the pushing pressure P is low.
Both A and high pressing force PB can be adjusted within a certain range. Oil is supplied from tank 12. 10 is a hydraulic pressure adjustment valve;
11 is an air pressure regulating valve.

The gap G can be adjusted to any value using an adjustment bolt 13 as shown in FIG. Furthermore, when the bent portion of the steel pipe 1 rotates or passes through the pinch roller 3 and the upper roller 3 becomes able to descend, the rod of the air cylinder 4 descends, pulling down the lower stopper 5, and Furthermore, the lower stopper 15 pulls down the upper stopper 7. In this case, oil to the upper part of the hydraulic cylinder 6 enters through the check valve 15. A lower limit position adjustment mechanism 14 for the upper roller 3 is provided to prevent the upper stopper 16 from lowering too much and at the same time to set the upper roller 3 by placing an appropriate minute gap on the surface of the steel pipe 1. .
Figure 4 shows the operating stroke of the upper roller 3 and the upper roller 3.
This shows the relationship between the pressure applied to the Table 1 shows the results obtained using the heat treatment apparatus according to the present invention and the conventional apparatus.

As described above, according to the present invention, since the pressing force of the pinch roller is controlled according to the amount of bending of the heat-treated member, the bending that occurs during heating is reduced compared to the conventional method, and the Even if it is bent, it passes through the pinch roller portion with little resistance, and has the advantage of preventing damage to the heating source.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a state in which a heat-treated member collides with a pinch roller, and FIG.
The figure is a partially enlarged detailed view of FIG. 1, and FIG. 4 is a diagram showing the relationship between the pressing force and the stroke of the pinch roller. In the figure, 2 is a heating coil, 3 is a pinch roller, 4 is an air cylinder, 5 is a lower stopper, 6 is a hydraulic cylinder,
7 is an upper stopper, 8 is a hydraulic solenoid valve, 9 is an air solenoid valve, 10 is a hydraulic pressure adjustment valve, 11 is an air adjustment valve, and 14 is an upper pinch roller lower limit position adjustment mechanism.

Claims (1)

[Claims] 1. While conveying the heat-treated member in its longitudinal direction, a heat source divided into a plurality of parts and a pinch roller consisting of two upper and lower rollers installed between the heat sources are In an apparatus for heat-treating by pressing the pinch roller through a cylinder, a lower stopper is provided at the upper end of the rod passing through the cylinder, and the lower stopper is attached to the lower end of the rod of a hydraulic cylinder installed above the cylinder. The rod of the hydraulic cylinder is moved up and down by a hydraulic control mechanism through the upper and lower stoppers, so that the cylinder rod is moved up and down. A roller lower limit position adjustment mechanism is provided,
A heat treatment apparatus characterized in that the pressing force of a pinch roller is controlled in accordance with the amount of bending of a heat treatment member passing therethrough. 2. The heat treatment apparatus according to claim 1, wherein the pressing force is controlled in two stages, low pressure and high pressure, depending on the upper and lower sides of a fixed amount of bending of the heat treated member.