JPH0726331A - Heat treatment method and heat treatment apparatus for metal body - Google Patents

Abstract

PURPOSE:To obtain a hardened material having excellent straightness by applying continuous quenching treatment while giving a fixed elongation ratio to a wire, bar or deformed material. CONSTITUTION:The quenching tretment is executed while giving tensile stress so as to develop 0.1-5% elongation to the metallic material 2 drawn out of winding device 1 by adjusting the number of revolutions of crawler type belts 3 and 6 arranged at the front and the rear parts of a heating device 4 and a cooling device 5. For the quenching, any of atomizing cooling down from the qunching temp., direct quenching by air cooling or stepwise quenching method by rapid cooling to 400-600 deg.C from the quenching temp. and then holding 2-10min and executing air cooling can be adopted according to the characteristic of the metallic material 2. Then the hardened metallic material 2 after completing the quenching is cut to a prescribed length by using a cut-off device 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method for a metal body and a heat treatment apparatus for producing a hardened wire, a rod and a profile having excellent straightness.

[0002]

2. Description of the Related Art Generally, small motors are used in audio equipment, measuring instruments, small precision machines, etc.
A large amount of% Cr martensitic stainless steel is used for micro shafts of small motors. This micro shaft often has a diameter of 1 to 3 mm and a length of about 50 mm. Conventionally, in these micro shafts, a wire wound in a coil shape is cut into a predetermined size, a large amount of the material is charged into a steel basket, and a quenching process is performed in a continuous furnace.

[0003]

Therefore, in the above-mentioned conventional example, the microshaft is deformed by its own weight because the heating time up to the quenching temperature of 1050 ° C. is long. Further, further deformation occurs in the subsequent oil quenching. On the other hand, since the wire wound in the coil shape itself is curved, this deformation adversely affects the end. As a result, in order to obtain the straightness of the microshaft, since the polishing is performed three times to manufacture, there is a problem that a polishing machine and a worker are additionally required for the polishing work. On the other hand, hardened wires of carbon steel or low alloy steel and steel bars are also widely used as abrasives having excellent straightness for rotating shafts and others. Since these hardened materials are also manufactured in the same process as the above-mentioned micro shaft, deformation of the hardened material becomes a problem, and an extra polishing process is used to solve the problem.

Further, there is a long-sized small profiled material, for example, a rail-shaped one is typical, and as the material, martensitic stainless steel and low alloy steel are used. In this case as well, bending deformation is caused. Occurs. In particular, there is a problem that it is difficult to correct after quenching, and a long product cannot be obtained. As described above, the longitudinal hardened material manufactured by the conventional method requires an additional polishing step in order to obtain straightness. Therefore, the present invention provides a heat treatment method and heat treatment apparatus for a metal body which produces a metal body having excellent straightness and reduces an extra polishing operation for obtaining the straightness and a polishing machine and workers involved in this polishing operation. The purpose is to provide.

[0005]

According to the present invention, a longitudinal metal body is heated to a quenching temperature while being applied with a tensile stress so as to cause elongation of 0.01 to 5.0%, and is then quenched and / or quenched.
Alternatively, it is a heat treatment method for a metal body, which is characterized by performing quenching by air cooling.

Further, the present invention provides a winding device for winding a long metal body, and pulling out the metal body from the winding device.
A first crawler belt for transporting, a heating device for heating the metal body carried in from the first crawler belt, and a cooling device for cooling the metal body heated by the heating device and carried out. A second crawler belt that pulls out the metal body from the cooling device, conveys the metal body, and applies a predetermined tensile stress to the metal body between the first crawler belt and the first crawler belt; / Or second
By adjusting the number of rotations of the crawler belt of
A tensile stress adjusting device for adjusting the predetermined tensile stress,
And a cutting device for cutting the metal body carried out from the second crawler belt into a predetermined length.

[0007]

According to the present invention, the longitudinal metal body, which is wound into the winding device and deformed into a circular shape, is heated to the quenching temperature while applying a tensile stress that causes elongation of 0.01 to 5.0%. Therefore, a metal body with excellent straightness can be manufactured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on its embodiments with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. The method of the present invention is applied to a long metal body in the range of 0.01-5.
This is a heat treatment method for a metal body which is heated to a quenching temperature while applying a tensile stress such that 0% elongation is generated, and is subjected to quenching quenching and / or air cooling quenching, which is carried out by the following heat treatment apparatus. A long metal body 2 is wound around the winding device 1. The longitudinal metal body 2 is a martensitic stainless wire in the present embodiment, but the constituent components and the cross-sectional shape thereof are not particularly limited as long as they are the longitudinal metal body 2. The first crawler belt 3 is a device that pulls out the metal body 2 from the winding device 1 and conveys the metal body 2. The heating device 4 is a device that heats the metal body 2 carried in from the first crawler belt 3.

The cooling device 5 is a device that cools the metal body 2 that has been heated by the heating device 4 and carried out. Cooling device 5
Consists of a water-cooled pipe 5a through which the metal body 2 passes, and a cooling chamber 5b through which the metal body 2 carried out from the water-cooled pipe 5a passes. However, if the quenching and / or air-cooling quenching is applied, The configuration and combination are not limited. Heating device 4
The metal body 2 carried out from the cooling may be directly sprayed with water, but if it is rapidly quenched into the martensite phase, the deformation becomes large. Therefore, in this embodiment, the two-stage cooling method is adopted, and the metal body 2 carried out from the heating device 4 has the water cooling pipe 5a.
It is cooled inside and subsequently introduced into the cooling chamber 5b. The cooling chamber 5b may have a system of a small amount of water spray, a fluidized bed, or a wind blast. When the metal body 2 is made of carbon steel and a low alloy, air quenching cannot be performed, so quenching is performed with oil or water in a spray state at the stage of the water cooling pipe 5a. The second crawler belt 6 is a device that pulls out the metal body 2 from the cooling device 5, conveys the metal body 2, and applies a predetermined tensile stress to the metal body 2 between the metal body 2 and the first crawler belt 3. Here, the first crawler belt 3 and the second crawler belt 6
The surface contacting the metal body 2 is made of rubber or the like, but the material is not particularly limited.

The tensile stress adjusting device (not shown) is the first
It is a device for adjusting a predetermined tensile stress by adjusting the number of rotations of the crawler belt 3 and / or the second crawler belt 6, and includes a computer or the like. In this embodiment, the length of the metal body 2 is 0.01 to
Adjust so as to apply a tensile stress such that 5.0% elongation occurs. The lower limit of 0.01% is the case where the deformation of the linear metal body 2 is small, and the upper limit of 5% is the tensile stress when the deformation amount is large and straightness cannot be obtained. The tensile stress adjusting device (not shown) may include a stress meter (not shown) that displays the tensile stress. The cutting device 7 is a device that cuts the metal body 2 carried out from the second crawler belt 6 into a predetermined length. The metal body 2 cut into the predetermined length is appropriately stored in a case or the like, and the series of heat treatment steps is completed.

The specific data of the present embodiment and the conventional example are shown below.

[Example 1] Table 1 shows a comparison of the characteristics when a 2.0 mmφ x 70 mm martensitic stainless steel shaft was heat treated in a conventional example and in this example. The tensile stress is 20 kg. The degree of curvature (μm) is the length of the outermost diameter when the shaft is rotated. In this embodiment, the bending degree, that is, the bending deformation is about 1/5 as compared with the conventional example.
And the number of polishing was also reduced to 1/3.

[Table 1]

[0012]

[Example 2] Table 2 shows an example in which a heat treatment was performed in the same manner as in Example 1 using Cr-Mo steel (0.35% C) having a diameter of 5 mm. Note that the quenching was performed by spraying with water when the quenching was carried out from the heating device 4. The tensile stress was set to 30 kg. In this example, the bending degree, that is, the bending deformation was reduced to about 1/5 and the number of polishing was also reduced to 1/3 as compared with the conventional example.

[Table 2]

[0013]

Example 3 Using a device of the present invention, a metal body 2 made of 13 mm steel wire having a diameter of 2.0 mm was subjected to a quenching temperature of 1050 ° C. while applying tensile stress such that elongation of 0.01 to 5.0% was produced. After heating, the heated metal body 2 is quenched at 400 ° C. or 600 ° C. with the water cooling pipe 5a, and thereafter,
Air-cooled quenching was performed in the cooling chamber 5b for 10 minutes or 2 minutes. As a result, the degree of curvature was reduced, and the values in Table 3 were obtained, indicating that the material was sufficiently annealed. The annealing time according to the conventional example required several hours, but according to this example, there is an advantage that the carbide is preferentially broken out and the annealing time can be significantly shortened to about 10 minutes.

[Table 3]

[0014]

INDUSTRIAL APPLICABILITY As described above, the present invention reduces the extra polishing work for producing a metal body having excellent straightness and the extra polishing work for obtaining the straightness and the polishing machine and the worker involved in this polishing work. Has the effect. Furthermore, in the present embodiment, a metal body such as a 13Cr steel wire heated to the quenching temperature is 400 to 60.
If quenching and quenching is performed at 0 ° C. and then air-cooling and quenching is performed for 2 to 10 minutes, carbides are preferentially extruded, and there is an advantage that the annealing time can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Winding Device 2 Metal Body 3 First Crawler Type Belt 4 Heating Device 5 Cooling Device 5a Water Cooling Tube 5b Cooling Chamber 6 Second Crawler Type Belt 7 Cutting Device

Claims (5)

[Claims] 1. A metal characterized by being subjected to quenching and / or air-quenching while being heated to a quenching temperature while applying a tensile stress that causes elongation of 0.01 to 5.0% to a longitudinal metal body. How to heat your body. 2. The metal body heated to the quenching temperature of 40
Quench quenching to 0-600 ° C, then 2-10 minutes,
The heat treatment method for a metal body according to claim 1, wherein air-quenching is performed. 3. A winding device around which a long metal body is wound, a first crawler belt for pulling out and transporting the metal body from the winding device, and a carry-in device for the first crawler belt. A heating device for heating the metal body, a cooling device for cooling the metal body heated by the heating device and carried out, and a first crawler belt for pulling out and transporting the metal body from the cooling device. Between the second crawler belt and the first crawler belt and / or the second crawler belt for applying a predetermined tensile stress to the metal body between A heat treatment apparatus for a metal body, comprising: a tension stress adjusting device for adjusting the tension stress; and a cutting device for cutting the metal body carried out from the second crawler belt into a predetermined length. 4. The heat treatment apparatus for a metal body according to claim 3, wherein the tensile stress adjusting device includes a stress gauge for displaying the predetermined tensile stress. 5. The heat treatment for a metal body according to claim 3, wherein the cooling device includes a water cooling pipe through which the metal body passes, and a cooling chamber through which the metal body carried out from the water cooling pipe passes. apparatus.