JP2007327105A - Laser beam heat-treatment method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam heat-treatment method and an apparatus therefor by which in the laser beam heat-treatment method for performing the heat-treatment processing by irradiating a rotated work with the laser beam and cooling, the sufficient hardened depth and the hardness can be obtained and the heat-treatment processing can continuously be applied. <P>SOLUTION: This laser beam heat-treatment method is performed as the followings: the rotated work is irradiated with the laser beam and a continued prescribed portion in the axial direction of the work is heated into the first prescribed temperature, then, during heating the continued other portion, at least axial direction of the work, the prescribed portion is forcedly cooled into a second prescribed temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for performing heat treatment such as quenching on a workpiece surface such as an automobile part or a machine part, and more particularly to a laser heat treatment method and apparatus for performing a heat treatment such as quenching using a laser beam.

  As a method for performing laser heat treatment such as quenching on a workpiece attached to a machine tool, there is a laser heat treatment method in which a workpiece is cooled after being irradiated with a laser beam. For example, a laser that is equipped with a laser oscillator in the vicinity of a multi-tasking machine, which is irradiated with a condenser lens through a mirror attached to the machine tool and then subjected to quenching by natural cooling. There is a heat treatment method (for example, Patent Document 1).

As another laser heat treatment method, for example, the member to be quenched is rotated a plurality of times, and simultaneously with this rotation, the quenching portion is irradiated with a laser beam to heat the entire quenching portion to a predetermined temperature, and then the laser beam irradiation is stopped. There is a laser heat treatment method for cooling the quenching part (for example, Patent Document 2).
JP 59-50983 A JP-A-57-171618

  However, according to the laser heat treatment method disclosed in Patent Document 1, since the rotating workpiece is heated by irradiating the laser beam and then cooled by natural cooling, from the A3 transformation point. No rapid cooling was performed, and high quality quenching could not be obtained.

  In addition, according to the laser heat treatment method disclosed in Patent Document 2, the heat treatment target portion of the rotating workpiece is heated by laser light, and then the laser light irradiation is stopped and cooled to perform quenching. There is a problem that the heat treatment cannot be performed continuously.

  Accordingly, an object of the present invention is a laser heat treatment method in which a heat treatment is performed by irradiating a rotating workpiece with laser light and then cooling the workpiece, and a sufficient quenching depth and hardness can be obtained. It is an object of the present invention to provide a laser heat treatment method and apparatus capable of performing a heat treatment process.

  According to the embodiment of the present invention, the predetermined workpiece continuous in the axial direction of the workpiece is continuously heated to the first predetermined temperature by irradiating the rotating workpiece with laser light, and the predetermined portion Is heated to the first predetermined temperature, and then the predetermined portion is forcibly cooled to the second predetermined temperature continuously at least during the heating of the other portion continuous in the axial direction of the workpiece. A laser heat treatment method is provided.

  According to another embodiment of the present invention, a rotating workpiece is irradiated with laser light, and a predetermined portion continuous in the axial direction of the workpiece is continuously heated to a predetermined temperature exceeding the A3 transformation point. Then, after heating the predetermined part to the predetermined temperature, forcibly cooling the predetermined part to room temperature continuously during heating of at least another part continuous in the axial direction of the workpiece. A laser heat treatment method is provided.

  Further, in the above invention, the first predetermined temperature or the predetermined temperature exceeding the A3 transformation point is obtained by irradiating the predetermined portion with the laser beam a plurality of times and heating. Also good.

  The cooling may be forcibly cooled from the first predetermined temperature to the second predetermined temperature within a predetermined time.

  Further, the cooling may be forcibly cooled from a predetermined temperature exceeding the A3 transformation point to room temperature within a predetermined time.

  According to another embodiment of the present invention, a rotating workpiece is irradiated with laser light, and a predetermined portion continuous in the axial direction of the workpiece is continuously heated to a first predetermined temperature, After the predetermined portion is heated to the first predetermined temperature, the predetermined portion is continuously forced to the second predetermined temperature at least during heating of another portion that is continuous in the axial direction of the workpiece. And then forcibly cooling to the second predetermined temperature after reheating to a third predetermined temperature lower than the first predetermined temperature. Provide a method.

  According to another embodiment of the present invention, a rotating workpiece is irradiated with laser light, and a predetermined portion continuous in the axial direction of the workpiece is continuously heated to a predetermined temperature exceeding the A3 transformation point. And, after heating the predetermined part to the predetermined temperature, forcibly cooling the predetermined part to room temperature continuously during heating of at least another part continuous in the axial direction of the workpiece, There is provided a laser heat treatment method characterized by reheating to a predetermined temperature below the A1 transformation point lower than a predetermined temperature exceeding the A3 transformation point and then forcibly cooling to a normal temperature.

  In the above invention, the first predetermined temperature, the A3 transformation point, the third predetermined temperature, or a predetermined temperature below the A1 transformation point may be obtained by applying the laser beam to the predetermined portion a plurality of times. It may be obtained by irradiation and heating.

  In the above invention, the cooling is forcibly cooled from the first predetermined temperature to the second predetermined temperature within a predetermined time, and from the third predetermined temperature. 2 may be forcibly cooled to a predetermined temperature of 2.

  Moreover, in the said invention, the said cooling may be forcedly cooled to normal temperature from predetermined temperature below the said A1 transformation point within predetermined time.

  According to another embodiment of the present invention, a laser processing tool that irradiates a rotating workpiece with laser light and continuously heats a predetermined portion continuous in the axial direction of the workpiece, and the laser processing A laser heat treatment apparatus, comprising: a cooling nozzle that is juxtaposed in a subsequent stage of the tool and for cooling the predetermined portion forcibly while heating at least another portion that is continuous in the axial direction of the workpiece. I will provide a.

  According to another embodiment of the present invention, a laser processing tool that irradiates a rotating workpiece with laser light and continuously heats a predetermined portion continuous in the axial direction of the workpiece, and the laser processing An infrared radiation thermometer for measuring the temperature of the workpiece heated by the tool and calibrating the heating parameters of the laser processing tool, and is arranged at the subsequent stage of the laser processing tool, and is continuous at least in the axial direction of the workpiece And a cooling nozzle for forcibly cooling the predetermined part heated by the laser beam during the heating of the other part to be performed.

  ADVANTAGE OF THE INVENTION According to this invention, sufficient quenching depth and hardness are obtained, and the laser heat processing method and its apparatus which can perform heat processing continuously can be provided.

  FIG. 1 is a plan view of a processing machine for performing a laser heat treatment method according to an embodiment of the present invention, in which a condensing head 600 that is a heat treatment tool is mounted on a mounting unit 200. In FIG. 1, an X direction is defined vertically and a Z direction is defined horizontally.

  The processing machine 1 is entirely controlled by a computer numerical control device (CNC) (not shown), and includes a processing machine body and an accessory device (not shown). Main accessory devices include an oil supply device, a cooling device, an air supply device, a coolant supply device, a chip collecting device, and a duct device for connecting these devices to the processing machine body.

  The processing machine 1 is placed on a bed 10 and supports a shaft or a long workpiece W so as to be rotationally driven, and mounted on the bed 10 to move in the X and Z directions. An X stage 301 and a Z stage 302 that perform positioning, and a mounting unit 200 that places the laser processing tool 500 and the coolant supply nozzle 700 on the Z stage 302 are included. In addition, for example, a turning tool or a grinding tool other than the laser processing tool 500 can be mounted on the mounting unit 200 and used as a combined processing machine.

  The work support drive unit 100 includes a headstock base 101 placed on a bed 10 and left and right headstocks 103 that are slidably movable via left and right headstock slide guides 102. Is equipped with a main shaft drive motor 104 for driving the main shaft 105 to rotate at a predetermined rotational speed. Each of the left and right headstocks 103 is configured to be able to slide in the Z direction independently on the left and right sides, hold the workpiece W between predetermined centers, and fix the position thereof.

  FIG. 2 shows a specific configuration of the laser processing tool 500, and is a diagram showing that the laser processing tool 500 includes a condensing head 600, a laser oscillator 601, and an optical fiber 602.

  The laser processing tool 500 includes a condensing head 600, a laser oscillator 601, and an optical fiber 602. The high-power laser oscillator 601 is placed on, for example, the bed 10 and is optically connected to one end of the optical fiber 602 via the optical fiber coupler 603, and the other end of the optical fiber 602 is connected via the optical fiber coupler 603. It is optically connected to the condensing head 600. The condensing head 600 has a condensing lens 620 for controlling the position in the X direction with respect to the workpiece W and irradiating the laser beam guided from the laser oscillator 601 with a predetermined laser beam size.

  The laser oscillator 601 includes a laser stack module 610a, 610b, 610c, and 610d, a polarization coupling plate 611, and a wavelength coupling plate 612. The laser stack module 610 is obtained by stacking a large number of laser light emitting elements to increase the output. Each laser stack module 610 performs beam shaping, collimated light in a predetermined linear polarization state, and then performs beam synthesis using a polarization coupling plate 611.

  The polarization directions of the laser stack modules 610a and 610b to be combined are orthogonal to each other. For example, in the polarization coupling plate 611 made of a polaroid film, a laser beam emitted from the laser stack module 610a is transmitted and emitted from 610b. The laser beam is reflected to be combined into one laser beam. The laser beams 610c and 610d are synthesized similarly.

  The oscillation wavelength of the laser stack modules 610a and 610b and the oscillation wavelength of the laser stack modules 610c and 610d are set to different oscillation wavelengths, and the wavelength coupling plate 612 transmits one of the different oscillation wavelengths and transmits the other one. By constituting the wavelength filter to reflect, it is combined into one laser beam on the emission side of the wavelength coupling plate 612.

  The laser oscillator 601 configured in this manner, for example, is stacked in 25 stages with an emission point interval of 2 mm, so that the optical output of the combined laser beam is 1 kW. Further, the oscillation wavelength is near-infrared light of 800 nm to 1000 nm, and this configuration has two wavelengths of 800 nm and 830 nm.

  The optical fiber 602 is, for example, a quartz optical fiber cable having a fiber core diameter of 600 μm. As shown in FIG. 1, the fiber cable length of the optical fiber 602 is set to a necessary and sufficient length so that the condensing head 600 can move within a predetermined processing range.

  The condensing head 600 includes a condensing lens 620 that condenses the laser beam guided from the optical fiber 602 via the optical fiber coupler 603 onto the processing surface of the workpiece W with a predetermined beam diameter, and is mounted. It is placed on the Z stage 302 via the unit 200.

  The condensing lens 620 is configured by one or a combination of two or more lenses, and condenses with a predetermined laser beam diameter on the processing surface of the workpiece W with, for example, NA 0.2.

  The diameter of the focused laser beam can be controlled by the position of the condensing head 600 with respect to the processing surface of the workpiece W, and can be set to vary from 1 mm to 10 mm, for example. Alternatively, by adopting a configuration having a mechanism for moving the condensing lens 620 on the condensing head 600 in the optical axis direction, the distance to the processing surface of the workpiece W is changed, so that the laser beam to be condensed is changed. The diameter can also be changed.

  Further, the laser beam focused on the processing surface of the workpiece W may have a substantially rectangular beam profile. By making the far field pattern into a substantially rectangular shape in the beam shaping in each laser stack module 610, the laser beam condensed on the processing surface of the workpiece W is, for example, a substantially rectangular shape of 1 mm × 1 mm to 10 mm × 10 mm. It can also be.

  In heat treatment, cooling is usually performed using a heat treatment coolant. Instead of the heat treatment coolant, it is also possible to use cooling air, water, liquid nitrogen, or the like. In the present embodiment, when a turning tool or a grinding tool is mounted on the mounting unit 200 and the present invention is carried out with a multi-task machine, the coolant supply nozzle 700 is provided for turning and grinding. It is possible to supply the coolant from the processing coolant supply nozzle 700 to the heat treatment target portion of the processing surface of the workpiece W. The heat treatment target portion is a predetermined portion irradiated with the laser beam, and a predetermined portion continuous in the axial direction of the workpiece W is a heat treatment range such as quenching. The coolant supply nozzle 700 is juxtaposed at the rear stage in the feed operation direction of the light condensing head 600. In FIG. 1, a coolant is supplied from a coolant supply device (not shown) to a heat treatment target portion via a coolant supply nozzle 700. Even if the supply nozzle 700 is not mounted on the mounting unit 200, it is sufficient if the coolant can be supplied to the heat treatment target portion of the workpiece W in accordance with the movement of the condensing head 600. Further, the means for forcibly cooling the heat treatment target portion of the workpiece W may be other than the coolant supply, for example, by cooling air or the like. In addition, the heat treatment can be performed by a self-cooling method in which the heat treatment target portion of the workpiece W is heated and then naturally cooled, regardless of the forced cooling.

  In order to measure the temperature of the heat treatment target portion of the workpiece W in a non-contact manner, an infrared radiation thermometer 800 is provided. The infrared radiation thermometer 800 may be mounted on the bed 10, but may be mounted on the mounting unit 200 so as to follow the laser beam feeding operation.

(Example of quenching by the laser heat treatment method according to this embodiment)
FIG. 3 is a diagram for explaining an example of quenching by the laser heat treatment method according to the present embodiment.

  In FIG. 3A, the laser beam width b of the laser beam LB applied to the processing surface of the workpiece W is adjusted by adjusting the distance L between the focusing head 600 and the processing surface of the workpiece W by moving the X stage 301. Is set by Note that, instead of or in addition to adjusting the position of the condensing head 600 in the X-axis direction, by changing the focal length of the condensing lens 620, the focusing angle of the laser beam LB is changed to change the position of the workpiece W. The laser beam width b on the processing surface may be changed.

  FIG. 3B shows that the laser beam LB is fed at a constant speed d in the Z-axis direction along with the movement of the condensing head 600, and the workpiece W is heated at the rotation speed N to heat the heat treatment target portion. Shows the locus of the region heated by the laser beam LB when is the next rotation period. Therefore, the pitch p can be expressed as p = d / N.

  Further, the heating region has a laser beam width b on the circumference of the workpiece W, and the laser beam LB spirals on the circumference of the workpiece W at a pitch p at which the laser beam LB is fed in the Z-axis direction per rotation of the workpiece W. Heat it up. Here, when the workpiece W is rotated while the workpiece W is heated while the laser beam LB is heated n times, the pitch p can be expressed as p = b / n.

  Therefore, from d / N = b / n, d = b · N / n. Therefore, required heat treatment conditions are set by appropriately combining the number of times of irradiation with the laser beam LB n times, the number of rotations N of the workpiece W, the laser beam width b, and the laser beam feed speed d from the heat treatment conditions. Set parameters to satisfy.

  FIG. 3C shows a case where the heat treatment is performed while rotating the workpiece W at a predetermined rotation speed N, operating the laser beam LB at a predetermined feed rate, and heating at a pitch p = b / 3. The locus of the region heated by the laser beam LB is shown. That is, with the rotation of the workpiece W, the heat treatment is performed while the portion of the workpiece W to be heat-treated is heated three times by the laser beam LB.

  FIG. 4 is a diagram for explaining an example of quenching by the laser heat treatment method according to the present embodiment with a process flow. Hereinafter, an example of quenching will be described with reference to a flowchart.

  The required quenching hardness, quenching depth, quenching range (quenching region in the Z-axis direction), and other heat treatment conditions such as the material of the workpiece W are input (S101). In this embodiment, the required quenching hardness is 250HB, the quenching depth is 3 mm, and the material of the workpiece W is S45C.

  Based on the heat treatment conditions in step S101, heat treatment parameters are determined. The heat treatment parameters are the rotational speed N of the workpiece W, the light output P of the laser beam, the laser beam width b, the laser beam feed speed d, the number n of times of heating by the laser beam at the heat treatment target, the quenching temperature, etc. ). In this embodiment, the rotational speed N = 300 rpm, the laser beam optical output P = 1 kW, the laser beam width b = 3 mm, the laser beam feed speed d = 5 mm / s, the heating frequency n = 3, and the quenching temperature is 850 ° C. is there.

  The workpiece W is supported by the main shaft 105 and rotated at a rotation speed N = 300 rpm (S103).

  The output of the laser oscillator 601 is adjusted, and the light is irradiated from the condensing head 600 through the optical fiber 602 so that the light output of the laser beam at the heat treatment target position on the surface of the workpiece W becomes P = 1 kW (S104). .

  The laser beam width b applied to the processing surface of the workpiece W is set to b = 3 mm by adjusting the distance L between the condensing head 600 and the processing surface of the workpiece W by moving the X stage 301. In this embodiment, the laser beam shape is a substantially rectangular shape of 3 mm × 3 mm (S105).

  In step S104, the condensing head 600 is adjusted in the X-axis direction, and the feed operation in the Z-axis direction is controlled. The feed control is performed by setting the feed rate d of the laser beam by d = b · N / n. Alternatively, the feed control may be performed by setting the feed control amount by the feed pitch p = b / n in the Z-axis direction (S106). That is, feed control is performed with d = 5 mm / s or p = 1 mm.

  After the condensing head 600 is moved by the X stage 301 and the Z stage 302 to the required processing start position in the quenching range of the workpiece W, the laser beam is applied to the heat treatment target portion of the workpiece W while performing the control of steps S103 to S106. Is heated to 850 ° C. or higher which is the A3 transformation point. As the workpiece W rotates, each heat treatment target portion is heated three times, which is a predetermined number of heating times (S107).

  The temperature of the heat treatment target portion, which is a laser irradiation unit, is measured by the infrared radiation thermometer 800 in a non-contact manner. The measured value of the temperature is fed back to the heat treatment parameter determination step S102, and if it is not heated to 850 ° C. or more which is the A3 transformation point, the heat treatment parameters such as the light output P of the laser beam are corrected (S108). .

  A coolant liquid in an amount of 0.2 L / min is supplied from the coolant supply nozzle 700 to a heat treatment target portion heated to a temperature of 850 ° C. or more which is the A3 transformation point which is the first predetermined temperature, and 500 ° C. per second. At this cooling rate, it is rapidly cooled to the second predetermined temperature, which is about 200 degrees in this embodiment (S109). The second predetermined temperature may be room temperature.

  As described above, the heat treatment is performed by continuously performing a series of steps in a predetermined quenching range in the Z-axis direction. In this example, a quenching hardness of 250 HB and a quenching depth of 3 mm were obtained.

  In addition to the quenching process described above, various heat treatment methods are possible. After being rapidly cooled to the second predetermined temperature of the above-described embodiment, that is, about 200 degrees, or room temperature, and then reheated to a temperature equal to or lower than the A1 transformation point (400 to 680 ° C.), which is the third predetermined temperature. A heat treatment method for forcibly cooling to the second predetermined temperature is possible. This heat treatment is a tempering process, which is hardened only by the quenching process but has a very brittle metal structure. Therefore, the tempering is performed as soon as possible after quenching.

(Effect of the present invention)
According to the heat treatment method of the present invention, the number of revolutions N of the workpiece W, the light output P of the laser beam, the laser beam width b, the laser beam feed speed d, etc. are adjusted so that the temperature becomes equal to or higher than the A3 transformation point. After sufficiently heating the target portion, the coolant is supplied to the heat treatment target portion and rapidly cooled. Therefore, in the place to be heat-treated, it is rapidly cooled after being heated sufficiently deep from the surface, so that the quenching depth can be increased, and sufficient hardness can be obtained by the rapid cooling, which enables high-quality heat treatment processing. Has an effect.

  Moreover, since the location to be heat-treated is heated a plurality of times, the quenching depth can be controlled by controlling the number of heating.

  Further, the heat treatment method according to the present invention is not limited to the quenching and tempering described above, and various heat treatment methods are possible. For example, it has an effect that various heat treatments such as normalizing by heating to the A3 transformation point or higher and then allowing to cool in the air become possible.

  In addition, the infrared radiation thermometer measures the temperature of the heat treatment target part of the workpiece W in a non-contact manner and feeds it back to the heat treatment parameter determination step. This improves the accuracy of the heat treatment temperature and makes it easy to control the quenching depth. It has the effect of becoming.

  In addition, the heat treatment method according to the present invention can continuously perform heat treatment while the workpiece W is chucked on the main shaft, so that it can be processed as one chuck with other processes such as turning and grinding, and the machining process can be consolidated. Therefore, by implementing the heat treatment method according to the present invention in a multi-tasking machine capable of turning, grinding, etc., there is an effect that a processing machine capable of roughing, heat treatment and finishing can be configured.

  Further, since the heat treatment method according to the present invention is heated by laser irradiation, the output of the laser can be controlled with high accuracy, and since the temperature measurement is fed back, the heating controllability is high. Therefore, the heating from room temperature can lower the temperature before the metal structure becomes coarse by raising the surface to a temperature higher than the target temperature and improving the heat conduction to the inside.

1 is a plan view of a processing machine for performing a laser heat treatment method according to an embodiment of the present invention, and is a view in which a condensing head 600 that is a heat treatment tool is attached to a workpiece processing unit 200. FIG. FIG. 3 is a diagram illustrating a specific configuration of the heat treatment tool 504, and is a diagram illustrating a configuration including a condensing head 600, a laser oscillator 601, and an optical fiber 602. It is a figure explaining the example of the hardening process by the laser heat processing method which concerns on this Embodiment. It is a figure explaining the example of the hardening process by the laser heat processing method which concerns on this Embodiment with process flow.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combined processing machine 10 Bed 100 Work support drive unit 101 Spindle base 102 Spindle base slide guide 103 Spindle base 104 Spindle drive motor 105 Spindle 200 Mounting unit 301 X stage 302 Z stage 500 Laser processing tool 600 Condensing head 601 Laser oscillator 602 Optical fiber 603 Optical fiber couplers 610a, 610b, 610c, 610d Laser stack module 611 Polarizing coupling plate 612 Wavelength coupling plate 700 Coolant supply nozzle 800 Infrared radiation thermometer

Claims (12)

Irradiating a rotating workpiece with laser light, and continuously heating a predetermined portion continuous in the axial direction of the workpiece to a first predetermined temperature;
After the predetermined portion is heated to the first predetermined temperature, the predetermined portion is continuously forced to the second predetermined temperature at least during heating of another portion that is continuous in the axial direction of the workpiece. Cool down,
And a laser heat treatment method. Irradiating a rotating workpiece with laser light, and continuously heating a predetermined portion continuous in the axial direction of the workpiece to a predetermined temperature exceeding the A3 transformation point;
After the predetermined part is heated to the predetermined temperature, the predetermined part is forcibly cooled to room temperature continuously during heating of at least another part continuous in the axial direction of the workpiece.
And a laser heat treatment method.   The first predetermined temperature or the predetermined temperature exceeding the A3 transformation point is obtained by irradiating the predetermined portion with the laser beam a plurality of times and heating it. 3. The laser heat treatment method according to 1 or 2.   2. The laser heat treatment method according to claim 1, wherein the cooling is forcibly cooled from the first predetermined temperature to the second predetermined temperature within a predetermined time.   3. The laser heat treatment method according to claim 2, wherein the cooling is forcibly cooled to a room temperature from a predetermined temperature exceeding the A3 transformation point within a predetermined time. Irradiating a rotating workpiece with laser light, and continuously heating a predetermined portion continuous in the axial direction of the workpiece to a first predetermined temperature;
After the predetermined portion is heated to the first predetermined temperature, the predetermined portion is continuously forced to the second predetermined temperature at least during heating of another portion that is continuous in the axial direction of the workpiece. Cooling
Furthermore, after reheating to a third predetermined temperature lower than the first predetermined temperature, forcibly cooling to the second predetermined temperature,
And a laser heat treatment method. Irradiating a rotating workpiece with laser light, and continuously heating a predetermined portion continuous in the axial direction of the workpiece to a predetermined temperature exceeding the A3 transformation point;
After heating the predetermined portion to the predetermined temperature, during the heating of at least another portion continuous in the axial direction of the workpiece, the predetermined portion is continuously forcibly cooled to room temperature,
Furthermore, after reheating to a predetermined temperature below the A1 transformation point lower than the predetermined temperature exceeding the A3 transformation point, forcibly cooling to room temperature,
And a laser heat treatment method.   The first predetermined temperature, the A3 transformation point, the third predetermined temperature, or a predetermined temperature below the A1 transformation point is heated by irradiating the predetermined portion a plurality of times with the laser beam. The laser heat treatment method according to claim 6, wherein the laser heat treatment method is obtained by:   The cooling is forcibly cooled from the first predetermined temperature to the second predetermined temperature within a predetermined time, and from the third predetermined temperature to the second predetermined temperature. The laser heat treatment method according to claim 6, wherein the laser heat treatment method is forcibly cooled.   8. The laser heat treatment method according to claim 7, wherein the cooling is forcibly cooled to a room temperature from a predetermined temperature below the A1 transformation point within a predetermined time. A laser processing tool that irradiates a rotating workpiece with laser light and continuously heats a predetermined portion continuous in the axial direction of the workpiece; and
A cooling nozzle that is juxtaposed in a subsequent stage of the laser processing tool, and forcibly cooling the predetermined part during heating of another part that continues at least in the axial direction of the workpiece;
A laser heat treatment apparatus comprising: A laser processing tool that irradiates a rotating workpiece with laser light and continuously heats a predetermined portion continuous in the axial direction of the workpiece; and
An infrared radiation thermometer for measuring the temperature of the workpiece heated by the laser processing tool and calibrating the heating parameters of the laser processing tool;
A cooling nozzle that is juxtaposed to the subsequent stage of the laser processing tool and forcibly cooling the predetermined part heated by the laser beam during the heating of at least another part continuous in the axial direction of the workpiece;
A laser heat treatment apparatus comprising: