JP2008196007A - Laser heat treatment apparatus and laser heat treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which can stably irradiate a work-piece to be worked with a laser light to rapidly heat a part to be worked of the work-piece, and can apply heat treatment such as quenching to the work-piece through rapid cooling, and to provide a heat treatment method therefor. <P>SOLUTION: The laser heat treatment apparatus comprises: a cooling nozzle unit having a main body part which is filled with a cooling fluid, a nozzle part for supplying the cooling fluid to a predetermined portion of the work-piece to be heat-treated, an inflow part through which the cooling fluid flows into the main body part, and an entrance window part which is arranged in such a position as to face the nozzle part and through which the laser light is incident on the inner side; a cooling-fluid supply unit which makes a predetermined inflow amount of the cooling fluid flow into the main body part; and a laser irradiation unit which makes the laser light transmit from the entrance window part to the inside of the main body part and makes the laser light irradiate the predetermined position of the work-piece through the nozzle part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser heat treatment apparatus and a laser heat treatment method, and more particularly to a laser heat treatment apparatus and a laser heat treatment method for performing a heat treatment by irradiating a workpiece to be processed with a laser through a coolant.

  The heat treatment of the metal workpiece is performed by heating to a specific temperature based on the material, shape, etc. of the workpiece, and cooling after the heating. As a device that heats the entire workpiece, a batch type that heats multiple workpieces at once using a large heating furnace by an electric heating method, a combustion heating method, etc., and a continuous type that processes while flowing in the heating furnace with a conveyor The heating furnace is generally used.

  On the other hand, as an apparatus for heat-treating a part of a workpiece or a surface layer, there is an apparatus that performs heat treatment by irradiating the outer peripheral surface of the workpiece with laser light.

  For example, in a state where the workpiece is placed in a cooling liquid (for example, water) that can pass through the workpiece, the workpiece is irradiated with laser light while passing through the cooling liquid, and the laser irradiated portion is rapidly cooled by the surrounding cooling liquid. There is a heat treatment method and a heat treatment apparatus for forming a hardened layer in a laser irradiation portion (for example, Patent Document 1).

  According to this, since the workpiece placed in the cooling liquid is irradiated with the laser, the laser irradiation portion can be rapidly cooled by the cooling liquid in contact with the irradiation portion immediately after the laser irradiation. In this method, heat can be forcibly taken away from the surface side of the workpiece simultaneously with the internal diffusion of heat, so even the relatively deep quenching part can be rapidly cooled, and deep quenching can be achieved. It becomes possible.

However, since the heat treatment apparatus disclosed in Patent Document 1 is configured to irradiate the workpiece with laser light while immersing the entire workpiece in the cooling liquid and transmitting the cooling liquid, the workpiece heated by the laser irradiation is rapidly cooled. Is suitable, but there is a limit to rapidly heating the workpiece, and there is a problem that it is not suitable for slow cooling of the workpiece.
JP 2004-315863 A

  Accordingly, an object of the present invention is to provide a heat treatment apparatus and a heat treatment capable of rapidly irradiating a workpiece to be processed with laser light to rapidly heat a processed portion of the workpiece, and capable of performing a heat treatment such as quenching by rapid cooling. It is to provide a method.

[1] In order to achieve the above object, according to the present invention, a main body that is filled with a cooling liquid, a nozzle that supplies the cooling liquid to a predetermined portion of a workpiece to be heat-treated, and the cooling liquid is the main body A cooling nozzle unit having an inflow portion that flows into the portion, an incident window portion that is disposed at a position opposite to the nozzle portion and through which laser light is incident, and a predetermined amount of inflow of the cooling liquid into the main body portion A cooling liquid supply unit that flows in, and a laser irradiation unit that transmits the laser beam from the nozzle portion to the predetermined portion of the workpiece through the inside of the main body portion from the incident window portion. A laser heat treatment apparatus is provided.
[2] The cooling liquid supply unit uses an inflow amount of the cooling liquid flowing into the main body portion from the inflow portion of the cooling nozzle unit, and an outflow amount of the cooling liquid supplied from the nozzle portion to the workpiece. The laser heat treatment apparatus according to the above [1] may be configured to be set larger than the above.
[3] In order to achieve the above object, the present invention supplies a cooling liquid to a predetermined portion of a workpiece to be heat-treated and irradiates the predetermined portion of the workpiece with laser light through the cooling liquid. A laser heat treatment method is provided.
[4] The workpiece is hardened by heating a predetermined portion of the workpiece to a predetermined temperature with the laser beam and holding the workpiece at the predetermined temperature for a predetermined time, and then cooling with the cooling liquid. The laser heat treatment method described in [3] above may be used.
[5] Further, the workpiece is heated to a predetermined temperature by the laser beam to a predetermined temperature and is maintained at the predetermined temperature for a predetermined time, and then cooled by the cooling liquid and the cooling gas. The laser heat treatment method according to [3] above, wherein the laser heat treatment method according to claim 3 is performed.

  According to the present invention, there is provided a heat treatment apparatus and a heat treatment method capable of rapidly irradiating a workpiece to be processed with laser light to rapidly heat a processed portion of the workpiece and capable of performing heat treatment such as quenching by rapid cooling. Can be provided.

(First embodiment of the present invention)
[Configuration of Heat Treatment Apparatus 1]
FIG. 1 is a perspective view showing a schematic configuration of a laser heat treatment apparatus according to the first embodiment of the present invention. FIG. 2 is a sectional view showing details of the cooling nozzle unit of the laser heat treatment apparatus according to the first embodiment of the present invention. The laser heat treatment apparatus 1 includes a base 10, a work support unit 20, a feed mechanism 30, a cooling nozzle unit 40, a cooling liquid supply unit 50, and a laser irradiation unit 60.

  On the base 10, the work support unit 20 and the feed mechanism 30 are placed, and a recovery groove 10 a is formed as a recess for storing the cooling liquid 200 in an area corresponding to the work support unit 20. . The cooling liquid supply unit 50 and the laser irradiation unit 60 may be placed on the base 10 or may be placed at a place other than the base 10.

  The work support unit 20 is configured to support the work W by a main shaft 21 and a tailstock shaft 22 so as to be rotatable by both centers, and to rotate the work W at a predetermined rotational speed by a main shaft motor 23 using a non-illustrated screw or the like.

  The feed mechanism 30 is configured such that a carriage 31 on which the cooling nozzle unit 40 is mounted is supported by a guide shaft 32 and a feed screw 33 and moved in parallel with the workpiece W (Z direction shown in FIG. 1). A ball screw (not shown) corresponding to the feed screw 33 is attached to the carriage 31 or a female screw is formed, and the carriage 31 is moved at a predetermined feed speed by controlling the rotation of the feed motor 34. The feed mechanism 30 may be a linear motor drive or a link mechanism, for example, instead of the feed screw 33 shown above.

  In addition, since the cooling nozzle unit 40 and the laser head 61 can be moved in the vertical direction (Y direction shown in FIG. 1) with respect to the carriage 31 by the Y stage 35, the distance between the nozzle portion 42 and the workpiece W, or The laser spot diameter of the laser beam LB on the workpiece W can be adjusted or controlled to be constant.

  The cooling nozzle unit 40 includes a main body portion 41, a nozzle portion 42, an inflow portion 43, and an incident window portion 44.

  The main body 41 has a hollow shape such as a cylinder or a rectangle in which a space is formed so that the cooling liquid 200 is filled therein. In the main body 41, a nozzle portion 42 that supplies the cooling liquid 200 to a predetermined portion of the workpiece W to be heat-treated, an inflow portion 43 through which the cooling liquid 200 flows into the main body 41, and a position facing the nozzle portion 42. An incident window 44 for receiving the laser beam LB is formed. The main body 41 is watertight and airtight except for the nozzle part 42 or the inflow part 43.

  The cooling liquid 200 is a liquid for cooling the workpiece W, and a liquid having a high transmittance is preferable. In particular, water can be preferably used, and cooling water is used as the cooling liquid 200 in the present embodiment. In the case of water, the transmittance is about 0.9 / cm in the wavelength range of about 800 nm to 1000 nm. In consideration of the transmittance, the optical path length through which the laser beam LB of the main body 41 is transmitted is preferably short.

  The nozzle portion 42 is provided with a supply hole 42 a for supplying the cooling liquid 200 to a processing location of the workpiece W. The supply hole 42a may have a hole diameter that allows the laser beam LB to pass therethrough and can supply the cooling liquid 200 in an amount necessary for cooling to the processing portion of the workpiece W. For example, the supply hole 42a is formed to 3 mm to 10 mm. Further, it is preferable that the nozzle portion 42, particularly the inner wall portion of the supply hole 42a, is smooth so that the cooling liquid 200 flowing out becomes turbulent and does not optically affect the wavefront of the laser beam LB. In addition, in order to give the main-body part 41 a fixed pressure on said conditions and to suppress generation | occurrence | production of a bubble, the one where the supply hole 42a of the nozzle part 42 is smaller is preferable.

  The inflow portion 43 is a portion into which the cooling liquid 200 having a predetermined flow rate flows into the main body portion 41, and a supply pipe 51 described later is attached in a watertight and airtight state via the packing 230.

  The incident window portion 44 is disposed and formed at a position facing the nozzle portion 42, that is, on the upper portion of the main body portion 41 in FIG. 2. The entrance window portion 44 is formed of a material having a high transmittance so that the laser beam LB can be transmitted, and a hole is formed in the main body portion 41 to bury a window glass 440 that is a material having a high transmittance in a watertight state. Is formed. When the main body 41 is made of a material having a high transmittance, the incident window 44 can be formed integrally with the main body 41. Further, since the window glass 440 is a part of the optical system of the converging laser beam LB, it is preferable to form the surface accuracy of the entrance surface 440a and the exit surface 440b with high accuracy.

  The cooling liquid supply unit 50 sends the cooling liquid 200 to the supply pipe 51 by the pump 53 in the unit main body and supplies the cooling liquid 200 from the inflow portion 43 of the cooling nozzle unit 40 to the inside of the main body portion 41. After being supplied to the workpiece W, the cooling liquid 200 accumulated in the recovery groove 10a of the base 10 is recovered to the cooling liquid supply unit 50 side via the recovery pipe 52 by the pump 53 in the unit body. The recovered cooling liquid 200 is sent again from the supply pipe 51 to the cooling nozzle unit 40 via a filter device, a temperature control tank, and the like (not shown).

  The pump 53 is configured to control the pump delivery pressure so that the delivery amount of the cooling liquid 200, that is, the inflow amount to the main body 41 of the cooling nozzle unit 40 can be set. Further, a flow meter is installed in a part of the supply pipe 51 or the inflow part 43 of the cooling nozzle unit 40 to measure the inflow amount of the cooling liquid 200 into the main body part 41, and based on this, the pump delivery pressure of the pump 53 is determined. It is good also as a structure to control.

  The laser irradiation unit 60 is configured by optically connecting a laser head 61 and a laser light source unit 62 through an optical fiber coupler 63 with an optical fiber 64, and the laser head 61 is mounted on the carriage 31. The laser head 61 is adjusted or controlled at a predetermined distance (working distance) with respect to the workpiece W, and locally heats the workpiece W with a laser beam LB having a predetermined spot diameter.

  Although a structure in which a high-power semiconductor laser is incorporated in the laser head 61 is possible as the laser, in this embodiment, in order to perform rapid heating deep from the surface of the workpiece W, the laser head 61 is separately provided. The laser light source unit 62 is provided. In addition, a carbon dioxide laser, a YAG laser, or the like can be used.

  The laser head 61 includes a condenser lens 65 for controlling the distance to the workpiece W and irradiating the laser beam LB guided from the laser light source unit 62 with a predetermined laser spot diameter. On the incident side of the laser head 61, the distance and center between the condenser lens 65 and the optical fiber 64 are adjusted by the optical fiber coupler 63, and the laser light LB from the laser light source unit 62 is efficiently guided to the condenser lens 65, On the other hand, an opening 61a is formed on the emission side, and the laser beam LB can be emitted with a predetermined laser spot diameter.

  The laser light source unit 62 includes laser stack modules 66a, 66b, 66c and 66d, a polarization coupling plate 67, and a wavelength coupling plate 68. The laser stack module 66 has a high output by laminating a large number of laser light emitting elements. Each laser stack module 66 shapes the beam to collimated light in a predetermined linear polarization state, and then performs beam synthesis using the polarization coupling plate 67.

  The polarization directions of the laser stack modules 66a and 66b to be combined are orthogonal to each other. For example, in the polarization coupling plate 67 made of a polaroid film, the laser light emitted from the laser stack module 66a is transmitted and emitted from 66b. The laser beam is reflected to be combined into one laser beam. The laser beams 66c and 66d are synthesized in the same manner.

  The oscillation wavelengths of the laser stack modules 66a and 66b and the oscillation wavelengths of the laser stack modules 66c and 66d are set to different oscillation wavelengths, and the wavelength coupling plate 68 transmits one of the different oscillation wavelengths and transmits the other. By constituting the wavelength filter to reflect, it is combined into one laser beam on the emission side of the wavelength coupling plate 68.

  For example, the laser light source unit 62 configured as described above has a stack of 25 stages with a light emitting point interval of 2 mm, so that the light output of the combined laser light 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 laser irradiation unit 60 focuses the laser beam LB guided from the optical fiber 64 via the optical fiber coupler 63 on the processing surface of the workpiece W with a predetermined laser spot diameter. The diameter of the focused laser spot can be controlled by the position (Y direction) of the laser irradiation unit 60 with respect to the processing surface of the workpiece W, and can be set to vary from 1 mm to 10 mm, for example.

(Operation of the first embodiment)
[Hardening treatment of steel using the laser heat treatment apparatus according to the first embodiment]
A workpiece W, which is a steel material to be heat-treated (for example, S45C), is rotatably supported at both centers by the workpiece support unit 20, and is rotated at a predetermined rotational speed by the spindle motor 23.

  The laser head 61 is set to a predetermined distance with respect to the workpiece W by the Y stage 35 and moved to the machining start position (Z direction) of the workpiece W.

The cooling liquid 200 (water) is caused to flow into the main body 41 from the inflow portion 43 of the cooling nozzle unit 40, and a part of the flowing cooling liquid 200 stays in the main body 41 and a part of the nozzle portion 42. To the processed portion of the workpiece W. Here, in the pump 53 of the cooling liquid supply unit 50, the cooling liquid 200 is supplied from the nozzle portion 42 to the processing portion of the workpiece W with a predetermined outflow amount, and the inside of the main body portion 41 is filled with the cooling liquid 200. As described above, the operation is performed by adjusting the delivery amount of the cooling liquid 200. That is, the pump 53 of the cooling liquid supply unit 50 uses the inflow amount of the cooling liquid 200 flowing from the inflow portion 43 of the cooling nozzle unit 40 to the main body portion 41 and the cooling liquid 200 supplied from the nozzle portion 42 to the work W. Control to be larger than outflow. After the above preparation (after time t ₁ ), the workpiece W is hardened by rapid heating and rapid cooling.

  Note that the temperature of the workpiece W is measured by, for example, an infrared radiation thermometer. The infrared radiation thermometer is a spot thermometer for measuring the temperature of the locally heated position, and can measure the temperature of the locally heated position of the workpiece W in a non-contact manner.

  FIG. 3 is a diagram showing the relationship between the time and the temperature of the machined portion when the steel material is quenched using the laser heat treatment apparatus 1 according to the first embodiment.

[Rapid heating step] t ₁ ≦ t ≦ t ₂
The laser light source unit 62 is operated so as to have a predetermined light output, and a predetermined portion of the workpiece W is heated from the laser head 61.

The laser beam LB emitted from the laser head 61 enters the main body 41 substantially perpendicularly from the incident window 44 of the cooling nozzle unit 40, passes through the cooling liquid 200 filled in the main body 41, and is emitted from the nozzle 42. The outer peripheral surface of the workpiece W is irradiated with a predetermined laser spot diameter, and a predetermined portion of the workpiece W is rapidly heated. At time t ₂ , the temperature of the heated portion rises to about 800 ° C. at which the temperature becomes higher than the austenite transformation temperature (about 730 ° C.).

[Feeding Step of Laser Head 61] t ₂ ≦ t ≦ t ₃
As described above, the laser head 61 is fed and operated in a state where a predetermined portion of the workpiece W is raised to about 800 ° C. by irradiation with the laser beam LB. Since the carriage 31 is moved in the Z direction at a predetermined speed by the feed mechanism 30, the laser head 61 moves together with the cooling nozzle unit 40 in the Z direction at a predetermined feed pitch. As for the movement amount, the laser head 61 is moved by a predetermined processing range (quenching range) of the workpiece W.

[Rapid cooling step] t ₃ ≦ t ≦ t ₄
Since the heating with the laser beam LB is not performed as the laser head 61 moves, the heated portion of the workpiece W heated by the laser head 61 is moved along with the movement of the laser head 61 by the cooling liquid 200 supplied from the nozzle portion 42. It is rapidly cooled sequentially. The time t _4, the workpiece W is cooled to about room temperature.

  By the above rapid heating and rapid cooling processes, the workpiece W is quenched to a predetermined depth within a predetermined range.

(Effects of the first embodiment)
The heat treatment apparatus according to the first embodiment of the present invention has the following effects.
(1) Since the workpiece W can be rapidly heated by the laser beam LB and rapidly cooled by supplying the cooling liquid 200, quenching from the surface of the workpiece W to a deep position, so-called deep quenching, can be performed.
(2) While the workpiece W is rapidly heated by the laser beam LB and simultaneously cooled by the cooling liquid (water), the feed mechanism can be heat-treated without overlapping heating of the laser beam LB, thereby suppressing the tempering phenomenon caused by twice heating. It is possible to quench the entire workpiece.
(3) When the workpiece W has a multi-stage shape, a constant cooling liquid can be supplied from the nozzle portion to the workpiece W, so that the thickness of the cooling liquid layer is kept constant and the distance of the laser beam is also constant. Therefore, stable heat treatment can be performed.
(4) Since the main body 41 of the cooling nozzle unit 40 is controlled on the cooling liquid supply unit 50 side so that the cooling liquid 200 is filled therein, the generation of bubbles in the optical path of the laser light can be suppressed, and the laser Light can optically pass through the cooling liquid 200 stably. As a result, the workpiece W can be subjected to highly accurate heat treatment, in particular, highly accurate quenching.

(Second embodiment of the present invention)
In the second embodiment of the present invention, the cooling gas 201 can be supplied to the inside of the cooling liquid supply unit 50 in the first embodiment of the present invention separately from the cooling liquid 200 (water). It is. In this embodiment, air (air) is used as the cooling gas 201, but other gases can also be used as the cooling gas.

  FIG. 4 is a sectional view showing details of the cooling nozzle unit of the laser heat treatment apparatus according to the second embodiment of the present invention. In FIG. 4, the cooling nozzle unit 40 includes a main body portion 41, a nozzle portion 42, an inflow portion 43, an entrance window portion 44, and an air inflow portion 45.

  The air inflow portion 45 is a portion into which the cooling gas 201 (air) having a predetermined flow rate flows into the main body portion 41, and the air supply pipe 501 is attached in an airtight and watertight state via the packing 230. From the air supply pipe 501, air of a predetermined air pressure is supplied into the main body 41 from an air supply device (air compressor) (not shown).

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(Operation of the second embodiment)
[Hardening treatment of steel using the laser heat treatment apparatus according to the second embodiment]
FIG. 5 is a diagram showing the relationship between the time and the temperature of the machined portion when a steel material is quenched using the laser heat treatment apparatus according to the second embodiment. Because until time t ₃ is the same as in the first embodiment, explanation will be given on the time t ₃ or later.

[Rapid cooling step] t ₃ ≦ t ≦ t ₄
Since the heating with the laser beam LB is not performed as the laser head 61 moves, the heated portion of the workpiece W heated by the laser head 61 is moved along with the movement of the laser head 61 by the cooling liquid 200 supplied from the nozzle portion 42. It is rapidly cooled sequentially. This rapid cooling is performed up to a dangerous area (about 250 ° C.) where the cracking is likely to occur.

[Slow cooling step with air] t ₄ ≦ t ≦ t ₅
When the temperature of the workpiece W reaches a dangerous area (about 250 ° C.), the supply of the cooling liquid 200 from the pump 53 of the cooling liquid supply unit 50 to the main body 41 is stopped. Thereafter, the work W is gradually cooled by supplying air from the air supply pipe 501 and blowing air from the nozzle portion 42 to the work W. The time t _5, near the end of its normal temperature, exit the cooling step.

  By the above rapid heating, rapid cooling, and slow cooling steps using air, the workpiece W is quenched into a predetermined range by a predetermined depth.

(Effect of the second embodiment)
The heat treatment apparatus according to the second embodiment of the present invention has the following effects in addition to the effects of the first embodiment.
(1) The cooling process after heating the workpiece W is made into two stages of rapid cooling and slow cooling process, and after cooling to the dangerous area (about 250 ° C), since it is based on the slow cooling process with air, the occurrence of burning cracks Therefore, workability and productivity can be improved.
(2) Since air can be supplied into the cooling nozzle unit 40, unnecessary cooling liquid (water) can be removed by air purge, and switching between wet and dry can be performed in a short time.
(3) By adjusting the supply amount of air, the amount of air blown from the nozzle part 42 to the workpiece W can be adjusted, and the cooling rate in the slow cooling process can be controlled.
(4) Since unnecessary cooling liquid (water) can be removed by air purge, when laser light from the laser head 61 is used, it is possible to suppress the influence on the optical system due to water droplets or water vapor.

(Third embodiment of the present invention)
The third embodiment of the present invention is an embodiment in which the workpiece W is laser-cut by the laser beam LB in the first embodiment of the present invention.

  FIG. 6 is a cross-sectional view showing details of the cooling nozzle unit portion of the laser heat treatment apparatus according to the third embodiment of the present invention.

  In FIG. 6, the laser beam LB is focused on a minute beam spot on the outer peripheral surface of the workpiece W, and gives a high energy density to the processing location. Since others are the same as those of the first embodiment, description thereof is omitted. In addition to the laser cutting described above, the laser beam LB can be applied to, for example, laser welding by narrowing the laser beam LB into a minute beam spot.

(Effect of the third embodiment)
The heat treatment apparatus according to the third embodiment of the present invention has the following effects in addition to the effects of the first embodiment.
(1) At the time of laser cutting, there is an effect that processing waste (sputtering, smoke, etc.) due to cutting can be removed by the cooling liquid 200.
(2) By supplying the cooling liquid 200 to the workpiece W, heat generated during laser cutting can be suppressed, and the thermal influence on the workpiece W can be minimized.

FIG. 1 is a perspective view showing a schematic configuration of a laser heat treatment apparatus according to the first embodiment of the present invention. FIG. 2 is a sectional view showing details of the cooling nozzle unit of the laser heat treatment apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between time and temperature when quenching a workpiece using the laser heat treatment apparatus according to the first embodiment of the present invention. FIG. 4 is a sectional view showing details of the cooling nozzle unit of the laser heat treatment apparatus according to the second embodiment of the present invention. FIG. 5 is a diagram showing the relationship between time and temperature when a workpiece is quenched using the laser heat treatment apparatus according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view showing details of the cooling nozzle unit portion of the laser heat treatment apparatus according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser heat processing apparatus 10 Base 10a Recovery groove 20 Work support unit 21 Main shaft 22 Tail shaft 23 Main shaft motor 30 Feed mechanism 31 Carriage 32 Guide shaft 33 Feed screw 34 Feed motor 35 Y stage 40 Cooling nozzle unit 41 Main body portion 42 Nozzle portion 42a Supply hole 43 Inflow part 44 Incident window part 45 Air inflow part 50 Cooling liquid supply unit 51 Supply pipe 52 Recovery pipe 53 Pump 60 Laser irradiation unit 61 Laser head 61a Opening part 62 Laser light source unit 63 Optical fiber coupler 64 Optical fiber 65 Condensing Lens 66 Laser stack module 67 Polarization coupling plate 68 Wavelength coupling plate 200 Cooling liquid 201 Cooling gas 230 Packing 440 Window glass 440a Entrance surface 440b Exit surface 501 Air supply pipe W Work LB Laser light

Claims (5)

A main body that is filled with cooling liquid, a nozzle that supplies the cooling liquid to a predetermined portion of a workpiece to be heat-treated, an inflow portion through which the cooling liquid flows into the main body, and the nozzle A cooling nozzle unit that is arranged at a position where the laser beam is incident and has an incident window for incident light;
A cooling liquid supply unit that causes the cooling liquid to flow into the main body portion at a predetermined inflow amount;
A laser irradiation unit that transmits the laser beam to the predetermined portion of the workpiece from the nozzle portion through the inside of the main body portion from the incident window portion;
A laser heat treatment apparatus comprising:   The cooling liquid supply unit has an inflow amount of the cooling liquid flowing into the main body portion from the inflow portion of the cooling nozzle unit larger than an outflow amount of the cooling liquid supplied from the nozzle portion to the workpiece. The laser heat treatment apparatus according to claim 1, wherein the laser heat treatment apparatus is configured to be set.   A laser heat treatment method characterized by supplying a cooling liquid to a predetermined portion of a workpiece to be heat-treated, and irradiating the predetermined portion of the workpiece with laser light through the cooling liquid.   The workpiece is hardened by heating a predetermined portion of the workpiece to a predetermined temperature with the laser beam and holding the workpiece at the predetermined temperature for a predetermined time and then cooling with the cooling liquid. The laser heat treatment method according to claim 3.   The workpiece is hardened by heating a predetermined portion of the workpiece to a predetermined temperature with the laser beam and holding the workpiece at the predetermined temperature for a predetermined time, and then cooling with the cooling liquid and the cooling gas. The laser heat treatment method according to claim 3.

Images