JPH0215637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing metal tools or machine parts;
In particular, it concerns local alloying methods.

(Conventional technology) Among the conventional techniques, so-called heat treatment of metals does not involve heating beyond the melting point, and there are limits to improving component segregation and refining the crystal structure, and adding new components is only possible from the surface. It was limited to a small amount and depth that could be spread. Furthermore, plating and thermal spraying, which attach dissimilar metals to the surface layer, have weak adhesion to the base material, which limits the ability to improve performance. Furthermore, attempts have recently been made to melt the metal surface layer with a laser beam, but this method causes blowholes and cracks and has not been put into practical use. In particular, the end face of blades and wear-resistant tools is often used as the working surface, but so-called attached blades require a complicated machining process, the shape of the end face is limited to a straight line or a gentle curve, and the material of the attached blade is was also severely limited.

(Problems to be Solved by the Invention) The present invention provides a method for manufacturing metal tools or machine parts with excellent performance, in particular, a method of manufacturing a metal tool or machine part with excellent performance, in particular, locally melting a base metal to form an alloy, solidifying the metal, and then forming the alloy. The present invention provides a manufacturing method by cutting to expose the parts.

(Means and effects for solving the problems) The gist of the present invention is to provide a deoxidizing agent on the surface of a base metal that is more easily oxidized than the base metal and has a lower melting point than the base metal; Additives made up of the alloy components to be added to the base metal are attached, melted and solidified using a laser beam or electron beam, and then cut to expose the molten solidified portion. This is a cutting surface alloying method characterized by the following. The present invention will be explained in detail below.

When many metals are melted, oxidation reactions proceed rapidly, generating gas and easily creating blowholes.

In the present invention, the oxidation reaction and rimming action of the molten metal are suppressed by coexisting with a so-called deoxidizer containing a substance that is more easily oxidized than the base metal, and the deoxidation products generated at this time are floated and removed from the molten metal. Separate. When the base metal is steel or a steel alloy, suitable deoxidizing substances include one or more of the well-known aluminum, silicon, manganese, titanium, zirconium, vanadium, or alloys thereof. The methods of adding these deoxidizing substances include powdering the additive containing the deoxidizing substance, applying it to the base metal using resin and solvent, drying it, and then melting it together with the base metal, or pre-welding it to the base metal. After heating, it melts together with the base material. To add alloying components, alloying elements are mixed with the additive along with a deoxidizing agent, and the mixture is applied and dried to melt together with the base metal. Alternatively, the deposited metal may be melted together with the base material after solidification or without waiting for solidification. When adding the above-mentioned deoxidizing agent and alloying element, scattering of the deoxidizing agent and alloying element can be prevented by adding a metal having a lower melting point than the base metal to the additive.

The heat source of the present invention can be a heat source capable of melting the base metal and additive elements, such as combustion gas, induction heating, electric arc, plasma, electron beam, or laser beam, but heat sources with high energy density, such as Electron beams or laser beams are most preferable from the viewpoint of improving material properties because local heating and melting and rapid cooling effects result in significant crystal refinement. Further, in the method of the present invention, in order to avoid air oxidation of the molten metal and air entrainment, it is preferable that the melting zone be filled with an inert gas such as argon or helium, or a gas that is difficult to react with, such as nitrogen. During cutting, in addition to blowing away the molten part with inert gas, oxygen can be blown to utilize the heat of the metal's oxidation reaction.

(Example) Next, embodiments of the present invention will be described.

Example 1 FIG. 1 shows the procedure of an example of the present invention. Plate thickness 4
Mix aluminum powder and molybdenum powder in a 1:1 ratio on the plate surface of carbon steel plate 1 of mm size, use silicone resin as a vehicle, adjust the viscosity with thinner, and apply a coating thickness using a brush.
It was applied to a thickness of 0.7 mm and dried (Step A). Next, a 10kW laser beam is focused on the application area to a diameter of 2mm,
The steel plate was moved at a speed of 40 mm/sec (Step B).
Next, focus the 10kW laser beam to a diameter of 0.8mm,
While spraying 5 liters/min of 10 kg/cm ² of oxygen onto the laser irradiated area, cutting was performed at a speed of 40 mm/sec at the same position as in step B (step C). FIG. 2 shows changes in the cross section of the steel plate of the part in which the present invention is implemented. In step A, additive 2 is bonded onto steel plate 1. In step B, a laser beam is used to obtain a molten zone, in which 10-20% molybdenum is added as an alloying component from additives.
It is added and instantly solidified to form the alloyed part 3. Aluminum in the additive functions as a deoxidizing agent and melts to prevent the additive from scattering. In step C, the alloyed portion 3 is cut so as to be exposed at the cut surface. In the example shown in FIG. 2C, the alloyed portion 3 is exposed at the cut portions on both sides, but the alloyed portion 3 can be exposed only on one side by shifting the cutting position. The cut surface is finished if necessary. In this example, the cross-sectional hardness of the alloyed part is 430 on the Bitkers hardness,
It is significantly hardened compared to the base material's Bitkers hardness of 180. In the alloyed part, blowholes and inclusion of oxides are not a problem.

Example 2 A 1:1 mixture of aluminum powder and tungsten powder was sprinkled on the surface of a carbon steel plate 1 with a thickness of 2 mm, a 5 kW laser beam was focused to a diameter of 8 mm, and the steel plate was moved at a speed of 80 mm/sec. , Tungsten and aluminum were bonded onto a steel plate by melting aluminum (Step A). Next, an 8 kW laser beam was focused on the coating area to a diameter of 2 mm, and the steel plate was moved at a speed of 80 mm/sec (Step B). Next, the 8 kW laser beam is focused to a diameter of 0.8 mm, and the laser irradiation area is filled with 5 kg/cm ² of argon gas.
Cutting was performed at the same position as in step B at a speed of 80 mm/sec while spraying at liter/min (step C). The amount of tungsten added to the molten part is 10 to 25%, and the Vickers hardness of that part is 560, which is significantly hardened compared to the base metal part, which has a Vickers hardness of 220. In this case, step A can be omitted, but if step A is omitted, the amount of tungsten added will vary to a low level, resulting in variations in quality and performance, which is not preferable. In addition, such highly hard alloy parts are extremely difficult to cut using normal mechanical cutting methods, but they can be easily processed using a laser beam or electron beam using an NC control panel, making them suitable for mass production.

Although the above results were obtained using a laser beam, similar effects can be obtained using an electron beam. However, the cut surface is cleaner with a laser beam that can spray gas than with an electron beam.

(Effects of the Invention) As described above, the present invention locally alloys the edges of metal tools or machine parts, gives them superior performance not found in conventional products, and cuts them all at once to the finished shape or just before it. It can be processed.
In the method of the present invention, alloy components can be added with high efficiency, blowholes and oxide entrainment defects can be ignored, and the industrial benefits are extremely large.

[Brief explanation of drawings]

FIGS. 1A, B, and C are explanatory diagrams of steps in an embodiment of the present invention, and FIGS. 2A, B, and C are diagrams showing changes in the cross section of a plate during the steps of an embodiment of the present invention. 1: Base steel plate, 2: Additive, 3: Alloying part,
4: Additive remainder, 5: Cut portion.

Claims (1)

[Claims] 1. A deoxidizing agent that is more easily oxidized than the base metal and has a lower melting point than the base metal on the surface of the base metal, and an alloy component to be added to the base metal. A method for alloying a cut surface, which comprises: adhering an additive, melting and solidifying with a laser beam or an electron beam, and then cutting to expose the melted and solidified portion. 2. The method for alloying a cut surface according to item 1 of the patent application, characterized in that cutting is performed with a laser beam or an electron beam.