JPS63241154A - Laser heat treatment for thermally sprayed film - Google Patents

Abstract

PURPOSE:To carry out efficient heat treatment causing no deterioration in characteristics without preheating, by moving a metallic base material on which a thermally sprayed film is formed and irradiating the thermally sprayed film with laser beam to apply laser fusing. CONSTITUTION:A metallic base material 15 on which a thermally sprayed film 17 is formed is moved in the direction of an arrow 18. When the thermally sprayed film 17 is reached the position of an irradiation unit 3, a laser beam 19 is applied to the thermally sprayed film 17 to carry out laser fusing, or further, a build up powder 23 is sprayed on the laser-fused thermally-sprayed film 17 to carry out build up. By the above heat treatment, a thermally sprayed film improved in workability, free from defects, excellent in adhesive strength, and having fine composition can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for laser heat treatment of thermally sprayed coatings formed on various mechanical parts, steel structures, various containers, and the like.

(Conventional technology) Conventionally, printing! For various mechanical parts with l'jJ parts or members used in high temperature or corrosive atmospheres,
To impart wear or corrosion resistance.

Plating, nitriding, or the formation of a thermally sprayed coating of wear-resistant or corrosion-resistant metal materials is performed, but in particular, in the case of forming a thermally sprayed coating, thermal spraying (plasma spraying, etc.) alone cannot melt the material in a very short period of time. Since the sprayed powder material flies onto the base material and solidifies, defects such as poor adhesion between the sprayed coating and the base material and pores and cracks in the sprayed coating are likely to occur. Defect-free processing was performed by etc.

However, in the case of laser fusing treatment of this thermally sprayed coating, the degree of cooling of the molten coating is very fast (approximately 1000℃/
5ec), cracks and the like occur during the volumetric expansion and melting/solidification process associated with the martensitic transformation of the base material. Therefore, in order to reduce this thermal effect, preheating is usually performed at a temperature of about 350° C. or higher before laser beam irradiation.

(Problems to be Solved by the Invention) However, when a base material on which a thermally sprayed coating is formed is placed in a constant temperature bath and preheated, the thermally sprayed coating may It brings about a change in its own characteristics.

Moreover, when the size and volume of the base material are large, handling is not easy, and a large volume of a constant temperature bath and an increase in preheating time are required, resulting in poor workability.

Therefore, the purpose of the present invention is to
It is an object of the present invention to provide a laser heat treatment method for a sprayed coating that can be efficiently heat treated without preheating and without deterioration of characteristics.

[Structure of the invention]

(Means and effects for solving the problems) The present invention has the following features:
A metal base material with a thermally sprayed coating formed on its surface is moved, and a laser beam is irradiated onto the moving thermally sprayed coating.
By fusing, heat treatment can be performed without preheating, and workability and properties can be improved.

Further, by providing a supply port for the powder material for build-up in the vicinity of the laser fusing irradiation unit and ejecting the powder material for build-up from this supply port, it is possible to arbitrarily select combinations of coating materials. In other words, ■ When mixing is difficult due to differences in physical properties (melting point, density, coefficient of thermal expansion, etc.) between various materials, ■ When the difference in melting point with the base material is large (porosity is likely to occur at the interface), ■ When the base material In the case of a combination of materials that have difficulty in bonding strength with other materials, the above processing procedure can solve the problem.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. First, the device will be explained. At the first Pj4, a plasma spray gun 2 is attached to one side of a box-shaped frame 1 (with an opening at the bottom), and a laser beam irradiation unit 3 is attached to the other side.

The plasma spray gun 2 has a cathode 4. It has a known configuration including an anode 5, a thermal spray powder supply port 6, an arc gas supply lower, a cooling water supply port 8, a cooling water discharge port 9, and the like. Moreover, the laser beam irradiation unit 3 is.

It is equipped with an optical system as shown in Fig. 2 or 3. Fig. 2 is a beam oscillation system equipped with a condensing lens 10, a reflecting mirror 11, and a vibrating mirror 12, and Fig. 3 is a beam oscillation system. This is a beam convergence system in which a multi-segment concave mirror 13 is provided.

Next, a heat treatment method will be explained. The surface of the base material 15 to be thermally sprayed is opposed to the opening of the frame 1, and an arc gas (Ar) supplied from the arc gas supply ml 7 is placed.

tie or inert gas such as Ne) is cathode 4, anode 4@5
Ultra-high temperature plasma jet 1 generated by voltage applied between
6, the thermal spray powder is supplied from the Ps spray powder supply port 6 and melted, and this is sprayed onto the base material 15 to form a thermal spray wave on the surface.
117 is formed. On the other hand, in response to the formation of this thermal spray wave [17], the base body 15 is sent in the direction of the arrow 18 in FIG.

When the sprayed coating 17 reaches the position of the irradiation unit 3, the laser beam 19 is supplied to the irradiation unit 3, and if the optical system shown in FIG. 2 is provided, the vibrating mirror 12 is vibrated at high speed. The thermal spray coating 17 is irradiated with a laser beam 20 with a linear energy distribution, and laser fusing is performed with the linear width. At step 13, laser fusing is performed by irradiating with a trapezoidal beam 21 having a uniform energy distribution to form a thermally sprayed coating with a fine composition that is free from defects and has good adhesion.

Note that the feeding speed of the base material 15 described above is adjusted by adjusting the time (or speed) required for forming the sprayed coating 17 by the plasma spray gun 2 and the time (or speed) required for laser fusing by the irradiation unit 3. If determined, the formation of the sprayed coating including heat treatment can be performed continuously.

Therefore, by configuring as above.

Laser fusing can be performed on the base material on which the sprayed coating has been formed without placing it in a constant temperature bath and preheating it, and the thermal sprayed coating can be heat-treated with improved workability.

In addition, as shown in FIG. 4, a build-up powder supply [122] is provided on the frame body 1 in close proximity to the laser beam irradiation head 3, and optional Inject the selected overlay powder (
By doing so (indicated by reference numerals 2 and 3), a defect-free and high-quality overlay (indicated by reference numeral 24) can be achieved.

The present inventor used 5US430 as a base material, and added oxide CAQ to this base material with 0. When overlaying with Ag or TiO□, first plasma spraying is performed on the base material to a thickness of approximately 1100 μ using N1-AQ powder as a base layer, and immediately Ag, 0
．． By performing the build-up by irradiating the laser beam while supplying the powder, a build-up with high bonding strength between base materials was obtained.

In this case, a segmented mirror was used in the laser beam irradiation optical system, and when the laser beam was irradiated at a speed of 2 m+/see and laser fusing was performed, a high-quality overlay with no defects was obtained.

〔Effect of the invention〕

Although the present invention is configured as described above, laser fusing can be performed without preheating after spraying the thermal spray powder material, improving workability and preventing deterioration of characteristics, and
! ! ! , it is possible to obtain a thermally sprayed coating with good adhesion and a fine composition with no defects.

In addition, by providing the supply port for the overlay powder close to the laser beam irradiation head, it is possible to select and combine any thermal spraying/overlay materials, resulting in defect-free and high-quality overlay.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an apparatus used in one embodiment of the present invention;
The figure is a schematic diagram of an optical system incorporated in an apparatus according to an embodiment of the present invention, FIG. FIG. 7 is a schematic diagram of the main parts of an apparatus according to another embodiment of the invention. 2... Plasma spray gun 3... Irradiation unit 15
... Base material 16 ... Plasma jet 17 ... Thermal spray coating 19 ... Laser beam 24 ... Overlay (8733) Agent Patent attorney Yoshiaki Inomata (1 person) Figure 1 Figure 2 Figure 8 Figure 4

Claims (2)

[Claims] (1) Moving the metal base material with the sprayed coating formed on the surface,
A method for laser heat treatment of a sprayed coating, characterized by irradiating the moving sprayed coating with a laser beam to perform laser fusing. (2) A laser heat treatment method for a thermal sprayed coating according to claim 1, wherein the moving thermal sprayed coating is injected with a powder material for overlay and irradiated with a laser beam to perform laser fusing and overlay.