JPH0825054A - Overlaying method of metal - Google Patents

Abstract

PURPOSE:To improve flow of molten metal by preliminarily coating the front face of a base material with a flux of borax, calcium chloride, potassium chloride, etc., and executing build up welding with plasma powder welding. CONSTITUTION:The front face of a base material 10 is coated with a flux 12. A plasma 8 is generated from a tungsten electrode 2. A metal powder 4 is jetted into the plasma 8 with a carrier gas 5. The metal powder 4 is molten and become into a deposited metal 9. A torch 1 is moved in A direction, the plasma powder welding is executed onto the front face of the base metal 10. Therefore, because a slug is generated while the base metal 10 is cleaned with the flux 12 and the flow of molten metal is made well, the build up welding layer is generated orderly. Further, the deposited metal is made smooth and uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of overlay welding by a plasma powder welding method such as improving the wear resistance of metal.

[0002]

2. Description of the Related Art Various methods such as nitriding, hard plating, and formation of carbide have been adopted as a technique for surface modification of metallic materials. Among these methods, the plasma powder welding method has been in the spotlight in recent years. The plasma powder welding method is a powder welding method using a plasma arc, in which the plasma arc generated between the base material and the electrode is a metal powder containing a component capable of achieving a predetermined purpose. Is supplied to the base metal to melt the powder metal, and the deposited metal layer is built up on the surface of the base metal. In this method, a metal with a good heat concentration in an inert atmosphere is used as a heat source, and the powdered metal is supplied and melted in the plasma, so that the material of the base metal can be modified. This is a method of selecting powder.

[0003]

As described above, this is an excellent plasma powder welding method, but if the material to be welded (base metal) is sent early in order to shorten the working time, the powder or base material will melt. Since the time was insufficient and the powder and the base material did not melt, the deposited metal was interrupted, and the deposited metal could not be continuously deposited, resulting in defective products. Also, if powder with a high melting point close to the melting temperature of the base metal is used, the melting balance with the base material is disrupted, and the base metal is melted before the weld metal is generated, resulting in defective products. was there. In order to solve these problems, it is necessary to adjust the welding current of plasma, the balance between the supply amount of metal powder and the feed amount of the workpiece (base metal), and the adjustment of the gap between the plasma torch and the workpiece. Until now, it has been necessary to take measures such as maintenance, but it takes a long time to take complete measures or a special jig is used, and sometimes sufficient measures are taken. There wasn't. Furthermore, the surface finish condition (oxidation condition, finished surface roughness, etc.)
Considering also, there were too many factors and it was difficult to take countermeasures. The present invention is to solve these problems.

[0004]

As a means for solving the above-mentioned problems, the present invention applies a flux of borax, calcium chloride, potassium chloride or the like to the surface of a base metal before plasma powder welding, and then plasma. This is a method of powder welding.

[0005]

The present invention resides in that flux is used in combination with the plasma powder welding method. Flux is a method that is often used in conventional welding methods, and the effect of flux is to dissolve obstructions intervening between the metals to be welded, especially oxides to improve the cleanliness of the metal and improve the flow of molten metal. It has been confirmed by the improvement and the improvement of the adhesion of dissimilar metals. . Since ancient times, it has also been used as a cage for joining steels of different components by forging. From the characteristics of these fluxes,
Plasma powder for melting metal powder and overlaying
If it is used for welding, it is possible to obtain a sufficient effect.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a plasma powder-welding method. Reference numeral 1 is a torch used for plasma powder welding. Reference numeral 2 is a tungsten electrode, and an electric current is passed between the tungsten electrode and a material to be welded (base metal) 10 to form a plasma state 8 in combination with the inert gas 3. At this time, it is protected by a shield gas 7 so that the atmosphere does not enter. When the metal powder 4 is jetted together with the carrier gas 5 in the plasma state, the powder metal is melted and the deposited metal 9 is formed on the base metal 10. In the meantime, a semi-solid solution state 9 exists. When the torch 1 is moved in the A direction and plasma powder welding is performed on the surface of the base metal 10, the flux 12 is applied on the surface of the base metal in advance, so that the base metal is melted. While cleaning, slag is generated in 13 parts, the flow of molten metal is improved, and the surface is successively welded by welding. Since the torch has a high temperature, water is passed through the cooling holes 6 to be used while being constantly cooled. FIG. 2 shows the progress of welding when the base metal 10 is viewed from above. Solid line with arrow 1
4 shows a state in which the torch 1 is being welded while weaving, and the flux 12 is applied to the front of the welding. FIG. 3 shows a defective state that occurs when welding is performed without using flux. The powder metal is melted and does not continue, and becomes a ball shape 15, and 16 parts of the base metal 10 are in an oxidized state. Weld metal is discontinuous and uneven, so it cannot be used

According to the present invention, when the durable metal is melted by the plasma powder welding method, the flow of the molten metal is improved, and the smoothness and uniformity of the deposited metal can be obtained. It is also possible to prevent the occurrence of defective products due to poor hot water flow.

[Brief description of drawings]

FIG. 1 shows the principle of plasma powder welding to a base metal.

FIG. 2 is a view seen from the upper surface of the base metal, showing the traveling direction of the nozzle.

FIG. 3 shows a state where the melting of the powder metal is bad and the surface is not built up.

[Explanation of symbols]

 1 Torch used for plasma powder welding 2 Tungsten electrode 3 Plasma gas 4 Metal powder 5 Carrier gas 6 Water cooling hole 7 Shield gas 8 Plasma 9 Weld metal 10 Base metal (workpiece) 11 Semi-solid solution layer 12 Flux 13 Slag 14 Nozzle trajectory 15 Solder metal solidified into a ball

Claims (1)

[Claims] 1. Improving the wear resistance of various metals,
In the method of overlaying the surface of the base metal with the plasma powder welding method, the overlay welding is performed by plasma powder welding after applying a flux of borax, calcium chloride, potassium chloride, etc. to the surface of the base metal in advance. A method characterized by: