JPH07284970A - Laser beam building-up method - Google Patents

Abstract

PURPOSE:To execute defectless build-up welding by previously providing a part to be built-up with a padding part adjacent to the part to be built-up and removing the padding part after build-up welding. CONSTITUTION:A cylinder head 1 for automobiles is made of an aluminum alloy and has a valve seat forming part 2 of the part to be built-up constituting a circulating form and is previously provided with the padding part 3 in an overhanging state over the entire circumference on the bore side thereof. Building-up is started from the padding part 3 by irradiating the part with a laser beam L while alloy powder 4 is supplied from a pipe 6 until the build-up is formed over the entire circumference of the valve seat forming part 2. The padding part 3 is removed by cutting, etc., to form the valve seat S by the build-up 5 after the building-up is executed. Simultaneously, the build-up shape, build-up welding conditions, etc., are limited to specific ranges. As a result, the build-up start part where a defect is liable to be caused by a deviation in the timing of the start of the metal powder supply for laser building-up and the irradiation start of the laser beam is removed together with the padding part 3 and the defectless build-up is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for overlaying an alloy material having excellent heat resistance and wear resistance on a base material made of, for example, an aluminum alloy by irradiating laser light.

[0002]

2. Description of the Related Art Laser overlaying of this kind is carried out in the manufacture of a cylinder head of an aluminum alloy automobile engine, for example, in order to improve the heat resistance, wear resistance and corrosion resistance of the valve seat. As shown in FIG. 3, the cylinder head 100 is previously provided with a groove 101 as a valve seat forming portion, and the laser beam L is irradiated while supplying the metal powder 102 to the groove 101, whereby the buildup portion 103 is formed. To form a valve seat. As shown in FIG. 4, an intermediate layer 104 is formed between the built-up portion 103 and the base material (cylinder head 100).

The laser padding of the valve seat as described above is described in, for example, Japanese Patent Laid-Open No. 62-150014.

[0004]

However, in the above laser overlay, it is difficult to match the timing of starting the supply of the metal powder 102 and the start of irradiating the laser light L, and there is a deviation in the timing. And the meat pad 1
The base material was diluted in the layer No. 03 and cracked C as shown in FIG.
Such defects may occur, and coping with this defect has been an issue in stabilizing the quality.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to obtain a defect-free buildup regardless of the timing of starting the supply of metal powder and the start of laser beam irradiation. It is an object to provide a laser build-up method.

[0006]

According to a first aspect of the present invention, there is provided a laser build-up method, wherein when the build-up is performed by irradiating a laser beam while supplying metal powder to the build-up part, the build-up work is carried out in advance. The meat-filled portion is provided adjacent to the portion, the meat-filled portion is started from the meat-filled portion, and the meat-laid portion is removed, and then the meat-filled portion is removed. According to a third aspect of the present invention, there is provided a laser padding method, wherein the portion to be lapped around is a valve seat forming portion of a cylinder head. A prefabricated part is provided on the inner diameter side, the buildup is started from the prefabricated part, and the buildup is performed on the entire circumference of the valve seat forming part. , Claim 4, claim 3
In the laser build-up method described above, the cylinder head is made of an aluminum alloy, and the valve seat molding part has a concave shape of R4 to 5 mm and the metal powder supply amount is 40 to 60 g / min. , The output is 4-5
kW and beam shape is (4-6) x (2-3) m
Laser light of m is processed at a processing speed of 0.5 to 1.0 m / min.
And the offset amount in the beating part is at least 5
mm, and the above configuration is used as a means for solving the problem.

[0007]

In the laser deposition method according to the first and second aspects of the present invention, by finally removing the punched portion, a defect occurs due to a timing difference between the start of metal powder supply and the start of laser light irradiation. Since the starting portion of the build-up that is apt to occur is removed, a build-up without defects can be obtained. Particularly, in the laser build-up method according to claims 3 to 5, there is no defect in the aluminum alloy cylinder head. A valve seat by padding can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the first to fifth aspects of the present invention will be described with reference to the drawings.
An example of the laser deposition method according to the present invention will be described.

A cylinder head 1 of an automobile engine, a part of which is shown in FIGS. 1 and 2, is made of an aluminum alloy (AC2).
It is made of A) and has a valve seat molding portion 2 as a portion to be laid up in the form of a lap, and a bulging portion 3 in a projecting state is provided in advance on the inner diameter side over the entire circumference. The valve seat molding portion 2 has a concave shape of R4.5 mm, and the thickness t of the beating portion 3 is 5 mm.

In the above-mentioned laser padding method for the valve sheet forming section 2, the laser beam L is irradiated while supplying the alloy powder 4 from the pipe 6 to start the padding from the punching section 3, and the valve sheet forming section 2 The padding 5 is formed all around.

At this time, Cu-10% was used as the metal powder 4.
Copper-based metal powder consisting of Al-5% Ni-3% Fe was used, and the supply rate was 50 g / min. Laser light L
Has an output of 4.5 kW and a beam shape of 5 ×
2.5 mm, the processing speed is 0.8 m / min
And Further, the amount of offset from the valve seat molding part 2 to the punched part 3 side was about 6 mm.

After the above-mentioned build-up, the beating portion 3 shown on the inside of the lines A and A in FIG. 2 is removed by cutting or the like to form the valve seat (S) by the build-up 5. In addition,
The valve seat is finished to form the seat surface.

As described above, according to the laser padding method,
By finally removing the beating portion 3, even if there is a slight deviation in the timing of starting the supply of the metal powder 4 and the start of the irradiation of the laser light L, the start of the build-up where defects are likely to occur due to the deviation of the timing. The portion was removed together with the beating portion 3, and a valve seat (S) having a defect-free overlay was obtained.

Further, the supply of the metal powder 4 and the laser light L are started.
Even if a defect such as a crack occurs at the starting portion of the build-up due to the deviation of the timing of starting the build-up of the
If so, the defective portion is completely removed together with the beating portion 3, and a good padding 5 can be obtained.

[0015]

As described above, according to the laser deposition method according to the first and second aspects of the present invention, defects are likely to occur due to a difference in timing between the start of metal powder supply and the start of laser light irradiation. Since the start portion of the build-up is removed together with the punched part, a good build-up without defects can be obtained, and the quality can be greatly improved. In particular, according to the laser build-up method according to claims 3 to 5, For example, in a cylinder head made of an aluminum alloy, it is possible to obtain a valve seat with a build-up without defects, and it is possible to maintain stable quality.

Further, since it is not necessary to strictly set the timing of starting the supply of the metal powder and the start of the irradiation of the laser light,
The control of the timing becomes easy, and the cost related to the processing machine can be reduced and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a valve seat portion of a cylinder head to which a laser overlaying method according to the present invention is applied.

FIG. 2 is a cross-sectional view illustrating a state after the valve seat shown in FIG. 1 has been built up.

FIG. 3 is a perspective view illustrating a conventional laser overlay of a valve seat.

FIG. 4 is a cross-sectional view illustrating a padding start portion.

[Explanation of symbols]

 1 Cylinder Head 2 Valve Seat Molding Part (Built-up Part) 3 Stamped Part 4 Metal Powder 5 Build-up L Laser Light S Valve Seat

Claims (5)

[Claims] 1. When supplying metal powder to the padding portion and irradiating it with laser light for padding, a padding portion adjacent to the padding portion is provided in advance and the padding is started from the padding portion. A method for laser overlaying, which comprises depositing the overlaying portion on the padded portion and then removing the punched portion. 2. The laser build-up method according to claim 1, wherein the build-up portion is formed in a circular shape. 3. The laser build-up method according to claim 2, wherein the portion to be built up that circulates is a valve seat molding section of a cylinder head, and a punching section is provided in advance on the inner diameter side of the valve seat molding section. A laser build-up method, characterized in that the build-up is started from the punching section, the build-up is performed on the entire circumference of the valve sheet forming section, and then the punching section is removed to form a valve seat by the build-up. 4. The laser build-up method according to claim 3, wherein the cylinder head is made of an aluminum alloy. 5. The valve seat molding part has a concave shape of R4 to 5 mm, the metal powder supply amount is 40 to 60 g / min, the output is 4 to 5 kW, and the beam shape is (4 to 5 kW).
6) Laser beam of (2 to 3) mm is processed at a processing speed of 0.5
The laser overlaying method according to claim 4, wherein irradiation is performed at ˜1.0 m / min and the offset amount at the punched portion is at least 5 mm.