KR960011080B1 - Making method of diamond tool and diamond tool - Google Patents

Abstract

Carbide powders or oxides powders are molded on the portion between the main body and the tip by jet molding of plasma heat source having ambient of argon, hydrogen, nitrogen and so on. Tungsten carbide powders, a mixture of tungsten carbide powders and cobalt powders, chromium oxide powders, aluminium powders or chromium carbide powders are molded on the portion when the main body is of carbon steel(SK,SCM), using argon and hydrogen as the ambient gas and controlling in 50-200psi/50-200cfm and 30-100psi/5-30cfm resp.

Description

Diamond Tools by Powder Spray and Manufacturing Method Thereof

1 is a cross-sectional view of a portion of a conventional diamond tool that does not attach a carbide tip over the contact portion between the base material and the tip portion.

Figure 2 is a cross-sectional view of the corresponding part is also attached to the conventional wear-resistant carbide tip over the contact portion in order to prevent wear, cracks and the like on the first degree.

Figure 3 is a cross-sectional state diagram of the corresponding area of the powder spray during the present invention.

Figure 4 is an explanatory diagram showing the powder angle of the thermal spray to the parent in the powder spray according to the present invention.

5 is a photomicrograph of a part of the diamond tool of the diamond tool obtained by the method of the present invention.

* Explanation of symbols for main parts of the drawings

1: Shank 2: Diamond Tip

3: slotted slot 4: conventionally attached carbide tips

5: spray coating part w: spray coating width

t: spray coating thickness

The present invention relates to a diamond tool using a powder spraying process and a manufacturing method thereof.

In diamond tools that are rotated in the diamond tool such as asphalt or concrete cutting, the cutting material powder or scrap such as asphalt and concrete, which are generated and accumulated in the area adjacent to the cutting material when cutting the cutting material, rotates. It receives the centrifugal force by force, and the force is applied to the upper adjacent part, so that the contact part between the diamond tip and the shank part is worn or cracked first, and even the fracture or tip is driven from the main body. Undercut phenomena have resulted in the failure of the diamond tip to wear out even before it is smoothly worn by the work, and the problem of inability to perform the cut operation has existed.

Therefore, in order to solve the above problems, the present invention may vary the shape of the part between the main body and the tip in various ways, and apply heat to the main body by applying a high-strength material such as cemented carbide to the main part to fix the main body with silver soldering to wear. Although this phenomenon has been prevented, this time, not only cracks and fractures occur in the grooves of the main body by the heat generated when the high strength materials are bonded to the diamond tool main body, but also the wear of the tip and the main body contact is still severe and troublesome. It was not fundamentally solved.

Therefore, in order to solve the above-mentioned problems fundamentally, the present invention has a high strength such as carbide-based powder or oxide-based powder in the state where the cemented carbide tip is attached to the site where the abrasion, crack, and peeling of the contact portion between the main body and the tip occur. It is an object of the present invention to provide a diamond tool and a method of manufacturing the same, wherein the powder having high hardness is sprayed onto the above-described part and coated so that the under cut phenomenon or the peeling phenomenon does not occur.

That is, the present invention is basically a diamond tool having a contact portion between the base material portion and the tip portion attached to the base material portion, the carbide-based spray powder or a plasma heat source at the contact portion of the base material portion and the tip portion; Spray the oxide-based spray powder, but adjust the gas such as argon, hydrogen, nitrogen as the spraying gas atmosphere to improve the bonding strength of the spray coating, and if the base material is SK-based or SCM-based carbon steel oral material, tungsten carbide (WC A) powder, a mixed powder of tungsten carbide powder and cobalt powder, or a chromium oxide (Cr ₂ O ₃ ) powder or an aluminum powder (Al ₂ O ₃ ) or chromium carbide powder (Cr ₃ C ₂ ) along a circumference of the contact portion The present invention relates to a method for producing a cutting diamond tool, and a tool manufactured by the method.

The present invention is described in detail below.

The present invention relates to a method of thermal spraying between a diamond tip and a circumferential tip of a main body that rotates a powdered powdered powder at high speed at a constant speed at high speed using oxygen and other fuel gases, and a tool thereof. Carbide-based materials such as WC), chromium carbide (Cr ₃ C ₂ ), molybdenum carbide (Mo ₂ C), titanium carbide (Tic), silicon carbide (SiC), and alumina (Al ₂ O ₃ ), chromium oxide (Cr ₂ O ₃ ), a single body of oxide-based thermal spraying materials such as silicon dioxide (SiO ₂ ) and molybdenum oxide (MoO ₂ ) alone, or a mixture of some spray materials It is composed of a spray material and sprayed in a plasma spray method by the heat source described above to be coated.

The main body (base metal) of the diamond tool according to the present invention is mainly selected from SK series (particularly SCM ₅ ) or SCM series (particularly SCM ₃ or SCM _4, etc.) material, because the strength as described above Because wear resistance is important. In this case, suitable thermal spraying materials for the main body, namely, the base material, strength, hardness, etc., are 82 to 100% of tungsten carbide (WC) and 18% or less of cobalt (Co) powder in the above-described carbide or oxide powder materials. It was found that a mixed powder mixed with chromium oxide (Cr ₂ O ₃ ), alumina (Al ₂ O ₃ ), or chromium carbide (Cr ₃ C ₂ ) powder is suitable. This is because the powders have high strength and good wear resistance, have a small difference in coefficient of thermal expansion with the base material, and have excellent adhesion with the base material. In particular, the test results show that tungsten carbide (WC) powder: cobalt (Co) powder It has been found that powders in the ratio of 100 to 82: 0 to 18 parts by weight are most suitable.

In performing the thermal spraying of the present invention described above, first, after pretreatment of the base material by blasting or the like, in the case of flame spraying, the particle speed is usually about 300 m / sec or more, flame temperature about 2,000 ° C. or more, and plasma arc spraying method. In this case, the particle speed is usually about 500m / sec or more and the flame temperature is over 3,000 ℃.

In addition, in the case of the present invention, it is preferable to preheat the base metal to about 150 ° C. or less in advance before spraying. However, in the present invention, if a high temperature plasma heat source is sprayed at a high speed to speed up the working speed, preheating is not usually possible. In this case, it is preferable to reduce the amount of powder injection in the initial stage and to increase the amount of injection powder gradually. Also, depending on the type of powder, thermal spraying may be performed at a constant powder supply per unit time without preheating.

During thermal spraying, oxidization and decarburization occur on the surface of the sprayed material due to high thermal spraying. Therefore, argon (Ar) gas and hydrogen (H ₂ ) gas are used as the atmosphere gas in order to prevent the bonding strength of the sprayed coating layer from deteriorating. In the present invention, the former is supplied at 50 to 200 psi, 50 to 200 cfm (ft ₃ / min), the latter to adjust the atmosphere gas to the supply of 30 to 100 psi, 5 to 30 cfm, the pressure and supply amount of the atmosphere gas Silver can be adjusted according to the powder material and the sprayed material. In other words, if this value is over-supplied, the target material (especially the diamond tip) melts and oxidizes and decarburizes. If this value is shorter than the above range, fusing of the sprayed powder to the workpiece is not performed. As a result, the coating adhesion weakens rapidly.

In the present invention, the contact portion between the diamond tip and the shank portion (base material) is 15 ° to 90 ° when the spraying angle of the gun (Gun) for the vertically parented material is α as shown in FIG. In particular, it has been found that 30-60 ° can obtain the most dense coating layer and that a coating layer having good abrasion resistance can be obtained.

Another important point in the present invention is as shown in FIG. 4, since the powder should be sprayed and coated to be narrower than the height (d) of the step formed between the diamond tip and the base material, thus reducing the cutting load in actual operation. In general, when d = 500㎛, it has been found that spraying with a thickness of t = 50 to 300㎛ has no peelability, excellent wear resistance, and a dense sprayed portion.

Another embodiment of the present invention will be described below. Here, the surface of the target part is not oxidized or decarburized by heating, and in particular, argon gas is used to prevent excessive processing and mixing of foreign substances in addition to this purpose. Here, an inert gas such as argon (Ar) and hydrogen (H ₂ ) gas were used as the atmosphere gas for the heat source.

Example

Tungsten carbide-cobalt (WC / Co.), Chromium carbide / nickel / chromium (Cr ₃ C ₂ / Ni / Cr), chromium oxide (Cr ₂ O ₃ ), alumina oxide (Al ₂ O ₃ ) powder was coated on a diamond tool having a diameter of 14 mm (354.2 mm) with varying thickness from 0.1 to 0.5 mm under the working conditions as shown in Table 1. Carbide materials generally react with air by heat during coating, and carbon is consumed. Therefore, there are many intermediate phases other than the original powder, but this problem does not occur in oxide materials.

The hardness of the layer coated with different kinds of powders is shown in Table 2 as tungsten carbide (WC / Co.), Chromium carbide / nickel / chromium (CrC / Ni / Cr), chromium oxide (CrO), and alumina oxide (AlO). ) Was the highest. In particular, in the early stage of coating, the adhesion strength between coating layers is very strong, but as the coating thickness increases, it is found that defects are gradually weakened by decarburization of raw material powder and oxidation caused by heat of coating layer. The hardness showed similar values, but the wear resistance was the best in WC / Co., Followed by the CrC coating layer. The alumina oxide AlO and the chromium oxide CrO also showed relatively good hardness, but the bonding strength of the oxide coating layer according to the oxide structure. It was measured that chipping phenomenon such as scratching caused by lack was generated.

As described above, the life of the undercut portion of the tool can be improved by approximately two to three times or more as compared with the conventional one, while maintaining good machinability, and the improvement in quality can be achieved by maintaining the cutting state as compared with the conventional one.

Claims (3)

In a diamond tool having a contact portion between a base portion and a tip portion attached to an end portion of the base portion, carbide is formed by a plasma heat source having an atmosphere gas such as hydrogen, nitrogen, and the like at the contact portion between the base portion and the tip portion. If the thermal spraying powder or the oxide thermal spraying powder is sprayed, and the base material is a SK-based or SCM-based carbon steel oral material, a tungsten carbide powder, a mixed powder of tungsten carbide powder and cobalt powder, or chromium oxide (Cr ₂ O ₃ ) powder or Aluminum powder (Al ₂ O ₃ ) or chromium carbide powder (Cr ₃ C ₂ ) is thermally sprayed along the circumference of the contact portion, and in this case, the atmosphere gases during the spraying are argon (Ar) and hydrogen (H ₂ ) gas. It is possible to control the supply in the range of 50 ~ 200psi / 50 ~ 200cfm and 30 ~ 100psi / 5 ~ 30cfm respectively to improve the coating adhesion of the cutting diamond tool Article methods. The cutting diamond tool according to claim 1, wherein the tungsten carbide (WC) powder and the cobalt (Co) powder are mixed uniformly in the range of 100: 82% to 0 to 18%, respectively. Manufacturing method. In a diamond tool having a contact portion between a shank and a tip portion attached to an end portion of the base portion, a tungsten carbide-based (WC) powder or a chromium oxide (WC) powder having a contact portion at the contact portion; When spraying the oxide powder of any one of Cr ₂ O ₃ ), chromium carbide (Cr ₃ C ₂ ) and aluminum powder (Al | ₂ O ₃ ), the spray thickness is the height of the jaw formed between the diamond tip and the base part. Cutting is characterized in that it has a dense abrasion-resistant coating site by spraying at a smaller thickness and by spraying the spray angle α of the thermal spray gun Gun to the vertical base material portion at 15 to 90 degrees. Method of making diamond tools.