JPH032333A - Method and apparatus for rotary melting treatment with laser beam - Google Patents

Abstract

PURPOSE:To execute melting treatment for uniformizing quality of a metal, alloy and compound material and improving the characteristics by irradiating a cylindrical material to be worked with laser beam, melting almost to center shaft, rotating and shifting the material to be worked in order. CONSTITUTION:In the vacuum chamber, the cylindrical material 3 to be worked is irradiated with the laser beam 1 through a condensing lens and rotated with a rotary device 4, and output of the laser beam and rotating velocity of the material 3 to be worked are regulated so that the melting depth comes to almost equal to the radius of the material 3 to be worked. By this method, the melting part 6 and the solidified part 7 are developed, and the melting treatment is executed to a part of the material 3 to be worked as round disk state by turning one round. After turning one round, the material 3 to be worked is successively shifted together with the rotary device 4 in the axial direction with a shifting device 5 and shifted at the velocity corresponding to the rotating velocity while rotating the material 3 to be worked to execute the melting treatment. By this method, the melting treatment can be executed to the whole of material 3 to be worked to the inner part, and the quality is uniformized and the characteristics is improved, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to melting treatment for homogenizing metals, alloys, and compound materials, improving their properties, and the like.

[Prior Art] Conventionally, there is a zone melting method as a method for such a purpose. This method is often used for purifying semiconductor materials such as Si and Ge, and for making impurity concentrations uniform, and its outline is shown in FIG. When the rod 3 to be processed is slowly passed through the coil 19 of the induction heater, only a portion near the coil melts and becomes homogenized. The melted part is held in place by surface tension, so it will solidify again without breaking down. However, if you want to increase the processing speed by increasing the length of the melted zone, or if you want to apply it to a thicker bar of material, it becomes difficult to support the melted zone only by surface tension, and there is a limit to the applicable size.

[Problems to be Solved by the Invention] On the other hand, a zone melting method in which a workpiece is moved vertically and melted by a laser beam or an electron beam is disclosed in Japanese Patent Application Laid-Open No. 56
It is shown in the publication No.-37292. A method of moving the workpiece vertically in this way is also often used, in which case the upper part 3a and lower part 3b of the workpiece 3 are moved independently and It is necessary to drive with delicate adjustment so that no tension is applied to the melting part.

In the figure, 21a and 21b are laser or electron beam sources, 22a
, 22b indicates a transmission window.

Moreover, the collapse of the molten part due to its own weight must be supported by surface tension, which is basically the same as in the case shown in FIG. 4.

[Means for Solving the Problems] The present invention enables deep welding, which is a feature of laser welding, and processing in the atmosphere, and also enables processing using a transparent window even in a vacuum or when aerobic control is required. Focusing on the simplicity of being possible with a sealed container with a simple structure, the present invention provides a new laser melting method and device that eliminates dependence on surface tension, which was a feature and limitation of conventional technology. (1) A processing method in which a cylindrical workpiece is irradiated with a laser to generate a molten zone and driven in the axial direction of the workpiece. The workpiece is melted with a laser beam, the workpiece is rotated around the axis, and after one rotation, the workpiece is sequentially fed in the axial direction, or while rotating, it travels in the axial direction at a speed commensurate with the rotation speed. A rotary melting processing method using a laser characterized by:

(2) The laser-based rotary melting method according to item (1) above, wherein the melting process is performed in a vacuum chamber.

(3) Fill the chamber with an inert gas such as argon, or a gas that causes a reaction with the workpiece such as oxygen or nitrogen, and spray the laser irradiation area intensively with a nozzle or the like, or fill the chamber with the gas. The method for rotary melting treatment using a laser according to item (1) above, characterized in that either of the following methods is performed:

(4) The method described above, characterized in that melting treatment and material composition adjustment are performed at the same time by feeding powder of metal, alloy, compound, etc. together with gas blown with a nozzle or the like.
3) The rotary melting treatment method using a laser as described in item 3).

(5) The laser according to any one of (1) to (4) above, characterized in that the end face of the workpiece is brought into contact with a refrigerant to perform forced cooling and accelerate cooling of the molten part. Rotary melt processing method.

(6) A rotating device for rotating the workpiece around the vertical axis of the cylindrical workpiece, a traveling device for driving the rotating device in the axial direction of the workpiece, and A rotary laser melting processing apparatus characterized by comprising a laser oscillator for emitting a laser beam to be irradiated and melted, and a condensing lens or a condensing mirror for condensing the laser beam onto the side surface of a workpiece. .

(7) a vacuum chamber for accommodating the rotating device and the traveling device and maintaining the interior in a vacuum or a predetermined atmosphere, and a laser transmission window provided on the chamber wall between the side surface of the workpiece and the condensing lens; A gas supply port for introducing gas into the chamber, a nozzle for blowing gas provided near the laser irradiation, and a hopper for storing powder to be supplied from the nozzle to the melting section are in contact at the end face of the workpiece. The laser-based rotary melting processing apparatus according to item (6) above, further comprising a rotating cooling disk through which a cooling medium is passed.

It is.

[Operation and Examples] The operation of the present invention will be explained in detail based on the example apparatus shown in the drawings. FIG. 1 is an explanatory diagram showing an embodiment apparatus for carrying out the method of the present invention, in which 1 is a laser beam emitted from a laser oscillator (not shown), 2 is a condenser lens, 3 is a workpiece, and 4 is a laser beam emitted from a laser oscillator (not shown). 5 is a rotating device for the workpiece, and 5 is a traveling device that moves the workpiece together with the rotating device in the axial direction. By adjusting the laser output and the rotation speed of the workpiece 3 so that the penetration depth is approximately equal to the radius of the workpiece, melted and solidified areas are formed as shown in 6 and 7 in the figure. breath,
- By rotating, a part of the workpiece is melted into a disk shape. At this time, the molten part 6 is almost the same as the part irradiated with the laser beam, and the surrounding area, including the immediately preceding solidified part 7, is in a solid state, so the molten part is reliably held by the surrounding area. In addition, since the proportion of the volume occupied by the molten part is smaller than in the conventional method, more rapid cooling is possible, and the uniform structure at the time of fusion is cooled and fixed almost as is. Naturally, by sending the molten part one by one in the axial direction and performing rotational irradiation, or by adjusting the traveling speed in the axial direction depending on the molten part and rotational speed, and performing spiral irradiation so that no unirradiated part remains, It is possible to melt-process the entire workpiece to the inside. As a result of the experiment, the depth of penetration into steel by laser was obtained as shown in Figure 2.
26φm at laser output 10kW and rotation speed 12rpa+
m (peripheral speed approximately 1m/m1n), 14kW.

It can be seen that a round steel bar of 30φmm (peripheral speed approximately tm/m1n) can be melted at 10 rpm. Note that when the laser output exceeds 10 kW, a metal mirror with higher light resistance than a lens is used for condensing the light.

It is generally known that the depth of laser penetration is deeper in a vacuum than in the air, and if the above process is performed in a vacuum chamber, even thicker materials can be processed. Furthermore, in a vacuum, contamination with impurities during material melting and reaction with the atmosphere can be eliminated, so a significant effect is expected in terms of the quality of processed materials.

Furthermore, after the chamber is evacuated to remove impurities, a high-purity reaction gas is sealed, and an example of a device that can actively utilize the reaction between the material and the gas that occurs during melting is shown in Figure 3. The chamber 8 is provided with a laser beam transmission window 9. In some cases, a condenser lens 2 is placed at the position of the transmission window.
You can also put it there and make it double as well. In the figure, 10 is a vacuum pump, and 11 is a pressure gauge. The reactant gas is filled into the chamber from the cylinder 12 through a gas supply port 13 provided in the chamber. If it is desired to promote the reaction between the molten part and the gas, a nozzle 14 may be provided near the laser irradiation point to spray the reaction gas directly onto the molten part 6.

Moreover, it is also possible not only to aim for simple homogenization of the material, but also to actively adjust the material composition. The powder 15 of the material to be added is added from the hopper 16 along with the gas through the nozzle 14, and is injected into the melting zone, where it is uniformly dispersed and solidified.

Further, depending on the material of the workpiece, there are cases where it is necessary to increase the cooling rate after melting. In that case, the workpiece may be forced to cool. An example of forced cooling is shown in FIG. That is, 1
Reference numeral 7 denotes a metal cooling disk through which a cooling medium such as water is passed, and a water supply/drainage port 18 is provided on the central axis so that the disk can rotate while being in contact with the end surface of the workpiece 3.

[Effects of the Invention] According to the present invention, it is possible to homogenize and improve the properties of metals, alloys, and compound materials without depending on the surface tension of the processed material as in the conventional zone melting method. Size limits can be significantly expanded. In addition, since functions such as the use of reaction gas and the addition of powder can be easily added, the functions of the zone melting method itself have been expanded, which has a remarkable effect with an extremely large ripple effect.

[Brief explanation of drawings]

Figures 1 and 3 are schematic diagrams showing an overview of a rotary melting processing apparatus according to an embodiment of the present invention, and Figure 2 is a diagram showing the depth of melt penetration of steel materials by laser as a function of processing speed and laser output. , 4th
FIG. 5 is a conceptual diagram of a conventional zone melting method. 1... Laser beam 2... Condensing lens 3...
Workpiece 4... Rotating device 5... Traveling device
6... Melting section 7... Solidifying section 8...
・Vacuum chamber 9...Laser transmission window lO...
Vacuum pump 11...pressure gauge 12...
Gas cylinder 13... Gas supply port 14... Nozzle 15... Additive material powder 16... Hopper 17... Cooling disk 18.
... Water supply and drainage port 19 ... Heater coil 20.
...Workpiece melting parts 21a, 21b...Laser or electron beam source 22a,
22b ・"Transmission window and 4 other people I Real [-/■in] Figure Vacuum exhaust pump Pressure gauge Gas cylinder Gas supply port Nozzle Additive material Powder (- Cooling disk water supply and drainage port

Claims (1)

[Claims] 1. A processing method in which a cylindrical workpiece is irradiated with a laser to generate a melted region and moved in the axial direction of the workpiece, in which the laser beam extends almost up to the center axis of the workpiece. melt,
Using a laser that rotates the workpiece around an axis and, after one revolution, sequentially feeds the workpiece in the axial direction or travels in the axial direction at a speed commensurate with the rotational speed while rotating the workpiece. Rotary melt processing method. 2. The laser-based rotary melting processing method according to claim 1, wherein the melting processing is performed in a vacuum chamber. 3 Fill the vacuum chamber with an inert gas such as argon, or a gas that causes a reaction with the workpiece such as oxygen or nitrogen, and spray it intensively onto the laser irradiation area with a nozzle, etc.
2. The rotary melting processing method using a laser according to claim 1, further comprising filling or blowing gas. 4. The rotary melting processing method using a laser according to claim 3, wherein the melting process and material composition adjustment are performed simultaneously by feeding powder of metal, alloy, compound, etc. together with the gas blown through a nozzle or the like. 5. The rotary melting processing method using a laser according to any one of claims 1 to 4, characterized in that forced cooling is performed by bringing a refrigerant into contact with the end face of the workpiece to accelerate cooling of the melted part. 6. A rotating device for rotating a cylindrical workpiece around the vertical axis of the workpiece, a traveling device for moving the rotating device in the axial direction of the workpiece, and an irradiation device for irradiating the workpiece. a laser oscillator for emitting a laser beam for melting;
A rotary melting processing apparatus using a laser, comprising a condensing lens or a condensing mirror for condensing a laser beam onto a side surface of a workpiece. 7 A vacuum chamber that houses the rotating device and the traveling device and maintains the interior in a vacuum or a predetermined atmosphere, a laser transmission window provided on the chamber wall between the side surface of the workpiece and the condensing lens, and the inside of the chamber. A gas supply port for introducing gas into the workpiece, a nozzle for blowing gas provided near the laser irradiation, a hopper for storing powder to be supplied from the nozzle to the melting part, and a rotary machine that rotates in contact with the end face of the workpiece. 7. The laser-based rotary melting processing apparatus according to claim 6, further comprising a cooling disk through which a cooling medium is passed.