JPH09227946A - Heat treatment of long parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable correction to the bending of long parts developed by quenching and tempering so that the center deflection at both end parts of the long parts comes within a prescribed bending allowance. SOLUTION: The long parts P quenched in a vertical type quenching furnace is quickly inserted into a bending prevention case 1 and cooled, and after lowering the temp. of the long parts P to the room temp., this parts is laid on a V groove 6 of a bending correction rail 4. A V groove 6 of a first pressing member 7 is abutted on the upper edge or the upper surface of the long parts P, and also, a second pressing member 8 is abutted on the lower surface of the bending correction rail 4. By this method, the bending correction rail 4 and the long parts P are interposed and tightly fastened, and then the tempering heat treatment is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is carried out in each heat treatment step of quenching and tempering a long part having a complicated shape,
The present invention relates to a heat treatment method for a long-sized component that keeps the bending accuracy within a predetermined finish tolerance range.

[0002]

2. Description of the Related Art Conventionally, a heat treatment method for a long component having a complicated shape, which is generally practiced, is performed in a quenching furnace (vertical furnace) in order to minimize bending of the long component P. It is carried out by suspending vertically as shown in.

Then, the suspended long part P is quenched at a quenching temperature of, for example, 950 to 1000 ° C. for 6 to 10 hours, then taken out of the furnace and cooled. In this way, the long part P is hardened to a certain hardness by the respective operations of quenching and cooling (rapid cooling).

In the above-mentioned long component produced by such heat treatment, at room temperature, a bending of about 2.0 to 1.0 mm occurs due to center runout at both ends (deviation of the center line at both ends).

On the other hand, in order to correct this bending, a bending straightening device as shown in FIGS. 5 and 6 is used to remove the long part P after quenching from the V of the bending rail 11 with high linear accuracy.
After being placed on the groove 12, these are interposed between the pressing member 14 with the V groove 13 and another flat plate-shaped pressing member 15,
Further, these are tightened with bolts 16 and nuts 17, and heat treatment for tempering is performed.

In the heat treatment in the tempering furnace at this time,
The heat treatment is performed at a temperature of 450 to 500 ° C. for 4 to 6 hours, and the operation is repeated 2 to 5 times. Even if this tempering process is performed, the bending of the long part P is a center runout at both ends, and a bending of about 1.0 to 0.5 mm remains.

[0007]

However, since the conventional heat treatment method for a long component is carried out as described above, the bending due to the quenching and tempering treatments is 2.0 to 1.0 mm and 1 respectively. There is a problem that the center runout at both ends of the long component cannot be set within the bending tolerance preset as a target value, which is relatively large as 0.0 to 0.5 mm.

Therefore, in order to fit within the bending tolerance, it is necessary to repeatedly carry out the tempering treatment similar to the above, but such repeated work causes a delay in the whole heat treatment work, and therefore, as a defective bending product. There is a problem in that it may be processed, and the cost of the product may increase.

The present invention has been made in order to solve the above-mentioned conventional problems, and the bending of a long part caused by quenching and tempering is prevented by a predetermined center runout at both ends of the long part. It is an object of the present invention to provide a heat treatment method for a long component which can be corrected so that it is within a bending tolerance.

[0010]

According to the method for heat treating a long part according to the present invention, a long part made of a metal material is suspended in a vertical quenching furnace and quenched, and then taken out from the vertical quenching furnace. Quickly insert the long part into a bend prevention case that has a cylindrical hole that is approximately the same as the external dimensions of the long part, cool it, and wait until the long part reaches normal temperature, then pull it out of the bend prevention case. After that, the long component is placed on the V groove of the bend rail, the V groove of the first pressing member is brought into contact with the upper edge or the upper surface of the long component, and the bottom face of the bend rail is contacted. A second pressing member is brought into contact with the second pressing member and the first pressing member so that the bending rail and the long component are sandwiched and squeezed to perform heat treatment for tempering. Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing a bending prevention case 1 as a bending prevention jig used for quenching a long part of the present invention, which is formed of an SC material or an SCM material in a cylindrical shape.

The inner peripheral surface of the cylindrical hole 2 of the bending prevention case 1 is honed within a range of strict dimensional tolerances, and the cylindrical hole 2 extends outward at one open end 60. The inlet taper portion 2a is formed by expanding into a conical shape in an angle range of 120 ° C. The bending prevention case 1 is formed in a shape and a size into which long components after quenching can be inserted in a substantially dense manner.

FIG. 2 shows a straightening device 3 used for tempering a long part. This has basically the same configuration as that shown in FIG.

That is, the bending correction device 3 includes a bending straightening rail 4 having a V groove 5 in the longitudinal direction and having a good linearity.
The first pressing member 7 as a pressing block made of an SC material or an SCM material for abutting the V groove 6 on the upper part of the long component P installed on the V groove 5 and the bottom surface of the bending rail 4 are provided. The second pressing member 8 as a flat pressing plate made of the SC material or the SCM material to be abutted, and the pressing members 7, 8
Bending rails 4 attached to and intervening in these
And a bolt 9 and a nut 10 that can be tightened so as to clamp a long component.

Next, a method of heat-treating a long part using the bending prevention case 1 and the bending correction device 3 shown in FIG. 1 will be described.

First, a vertical quenching furnace is used as a quenching furnace,
A long component P having a complicated shape is placed in a suspended manner in the same manner as that shown in FIG. 4, and in this state, quenching is performed at 950 to 1000 ° C. for 6 to 10 hours.

Then, after the quenching is completed, the long part P is held in the quenching furnace for a certain period of time, and then the long part P is taken out of the quenching furnace to quickly and quickly bend the case 1 shown in FIG. 3 is inserted into the cylindrical hole 2 from the inlet taper portion 2a side in the longitudinal direction, as shown in FIG.

Then, with the long part P inserted in the bending prevention case 1, the long part P is gradually cooled while being left at room temperature.

Next, after waiting for the long part P to reach room temperature, the quenched long part P is taken out from the bending case 1 and, as shown in FIG. 2, on the V groove 5 of the bending rail 4. Place on. Then, the V-groove 6 of the first pressing member 7 is brought into contact with the upper part of the long component P on the V-groove 5 so as to cover it, and the lower surface of the bending rail 4 is provided with a second flat plate. It is supported by the pressing member 8.

In this way, the bending rail 4 is
When sandwiching the long component P placed in the V groove 6 of the second pressure member 7 and the first pressure member 7, the plurality of bolts 9 protruding from or inserted into the edge portion of the second pressure member 8 are inserted. Are respectively inserted into bolt holes (not shown) arranged to face the edge of the first pressing member 7.

Then, by screwing the nut 10 into the bolt 9 protruding from the bolt hole of the first pressing member 7,
The bending rail 4 and the long part P are simultaneously pressed by the pressing members 7 and 8. By strengthening this screwing, the clamping force is gradually increased, and the long part P is on the V groove 5 of the bending rail 4 and the bending is straightened by following the parallel surface thereof. .

Then, in this state, 450-
The long part P is tempered at 500 ° C. for 4 to 6 hours, and this operation is repeated twice. In this case, the bending is recorded by a shim liner such as a copper plate according to the bending degree and the state of the long part P, the gap is adjusted, and the bolt 9
Tighten the nut 10 to. By doing so, it is possible to make the center runout at both ends of the long part P fall within a predetermined bending tolerance as a target value.

The inlet taper portion 2a of the cylindrical hole 2 is
It is provided to facilitate the work of inserting the long part P into the cylindrical hole 2.

The bending rail 4 is SC
After rough machining to finish dimensions with material or SCM, and then annealing for strain relief, the parallelism of the upper and lower surfaces has been severely finished, and the V groove 5 is also finished to an accuracy within the range of finishing tolerance. What is used is used.

[0025]

As described above, according to the present invention, a long component made of a metal material is hung in a vertical quenching furnace and quenched, and the long component taken out from the vertical quenching furnace is quickly removed. After inserting into a bending prevention case having a cylindrical hole that is approximately equal to the external dimensions of the long component and cooling, waiting for the long component to reach room temperature, and pulling it out from the bending prevention case, the long component The component is placed on the V groove of the bending rail, the V groove of the first pressing member is brought into contact with the upper edge or the upper surface of the long component, and the second pressing member is attached to the lower surface of the bending rail. Abutting, and sandwiching the bending rail and the long component by the second pressing member and the first pressing member, and squeezing them.
Since the heat treatment for tempering is performed, the bending of the long part caused by quenching and tempering can be corrected so that the center runout at both ends of the long part is within the predetermined bending tolerance. As a result, there is an effect that low-cost long components that have no or only a slight amount of heat treatment and are heat-treated can be easily manufactured in large quantities without defective products.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a bending prevention case used for carrying out a heat treatment method for a long component of the present invention.

FIG. 2 is a front view showing a straightening device used for carrying out the heat treatment method for a long component of the present invention.

FIG. 3 is a cross-sectional view showing a method of using the bending prevention case of FIG.

FIG. 4 is a front view showing a suspension state of a conventional long component during quenching.

FIG. 5 is a front view showing a conventional bending correction device.

FIG. 6 is a side view showing a conventional bending correction device.

[Explanation of symbols]

 P Long part 1 Bending prevention case 2 Cylinder hole 4 Bending rails 5, 6 V groove 7 First pressing member 8 Second pressing member

Claims (1)

[Claims] 1. A cylinder for suspending and quenching a long component made of a metal material in a vertical quenching furnace, and quickly removing the long component taken out of the vertical quenching furnace into a cylinder having substantially the same outer dimension as the long component. It is inserted into a bending prevention case having a hole, cooled, waits for the long part to reach room temperature, and is pulled out from the bending prevention case. Then, the long part is placed on the V groove of the bending rail. The V-groove of the first pressing member is brought into contact with the upper edge or the upper surface of the long component, and the second pressing member is brought into contact with the lower surface of the bending rail. A heat treatment method for a long component, characterized in that the bending rail and the long component are sandwiched and squeezed by the first pressing member and a heat treatment for tempering is performed.