JPS59187407A - Solid drill with extremely-hard tip - Google Patents

Abstract

PURPOSE:To prevent the breakage of a chisel edge and enable the high-speed cutting by consolidating extremely-hard alloys matching the characteristics of a drill compositely and metallurgically to constitute the drill. CONSTITUTION:A stiff, extremely-hard alloy 5 is used for a non-cutting section at the center with a slow cutting speed, and on the other hand an extremely- hard alloy superior in abrasion resistance to the said extremely-hard alloy and a steel shank 6 are used for the tip periphery with a high cutting speed to form this drill. Thereby, specific features of each raw material can be satisfactorily exerted. Accordingly, it can thoroughly withstand an excessive thrust force, the breakage of the central edge and the abrasion or deterioration of the peripheral cutting section is reduced, and it can withstand high-speed rotations under a strong thrust force.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Application of Kinki Va- The present invention relates to a drill used for drilling holes in 13 iron or steel materials.

(B) Conventional technology and its problems Since the end of 1JF, high-speed steel drills have been widely used for drilling r1 materials such as general steel materials and cast iron, but there has been a strong demand for improving the efficiency of drilling work. 11'1 Nowadays, there are an increasing number of cases in which the rotational speed of the drill is increased to meet the demand, and in such cases, a problem arises in the durability of drills made of high-speed corrugated steel. In other words, when the rotational speed of the drill is increased, the cutting speed at the circumference of the trilta V is naturally higher than that at the center, which causes the I? 44L, the deterioration becomes severe. As a countermeasure to this, cemented carbide with a loaf-resistant mouth/1 light is sometimes used as a drill material, but in the case of drill cutting, no matter how fast it rotates, the center part (near the chisel blade) Because the cutting speed cannot be increased, conductor cutting cannot be performed, and therefore, extremely strong strength is required in that part.

For example, in order to improve work efficiency, the first problem with carbide drills that use cemented carbide at the tip of the drill is that cemented carbide has inferior transverse rupture strength compared to, for example, high-speed steel. When drilling into the metal body at the tip of a drill, the center cutting edge often breaks.

The second problem is that when the patient is deaf (i111 degrees -1-
This is the point at which cracks occur on the cemented carbide side at the joint between the cemented carbide part and the steel part due to the difference in thermal expansion coefficients due to heating. Also,
The I-rill is required to withstand excessive thrust force, and on the other hand, it is necessary to provide a continuous groove on the outer periphery to remove chips J-11, which reduces the effective cross-sectional area of the main body. Parts that are not involved in the process must also have high strength, and each part of a typical twist drill housing requires different characteristics.

(c) Means for solving the problem The present invention has been developed to meet the requirements of lR2.
The drill is constructed by combining cemented carbide metals that meet Fj properties and metallurgically integrating them. The main objectives of the present invention are, firstly, to prevent chipping of the chisel blade, and secondly, to provide a carbide optical drill capable of high-speed cutting. The tip of the trill is made of a different type of cemented carbide in a concentric solid state, and the center part is made of a material with higher toughness than the surrounding part, and the material is metallurgically joined to the steel shank. It is a carbide-tipped Mutatoril with a characteristic of 1. This will be explained in detail below with reference to the drawings.

Figure 1 shows the conventional tip Muktoril, 1 is carbide tip 2
indicates the joint between the steel shank and the carbide tip 1. As mentioned above, drills with such a structure are made of cemented carbide, which has poor toughness, which causes chipping at the cutting edge and causes cracks to occur at joints with steel due to thermal fatigue and thermal stress. Figure 2 is a cross-sectional view of the composite type carbide optical star drill obtained by the present invention. The tip 5 is a high-toughness carbide tip with high toughness, and the high-toughness tip is attached to the flange of the holder, and the flange is joined to the steel shank. If the diameter of the high-toughness carbide tip 5 is 02 to 0.4 (7', preferably 02 or more) of the drill diameter, the effect of the high-toughness carbide tip cannot be exhibited.
If it exceeds 04, the area around the chisel will wear out quickly. Here 1
・The resistance of this type of high-toughness carbide tip is 27 D'
/rrs' or "2" is preferable; if it is less than that, it becomes fragile and the purpose of the present application cannot be achieved. The transverse rupture strength of the carbide tip with high wear resistance is preferably 270'', /flJ' (1:+,j), and materials with excellent wear resistance are preferred.

B) Embodiment FIGS. 2, 6 and 4 show an embodiment of the present invention. Figure 6 shows the shape of a high-toughness cemented carbide chip.The cylindrical part 8 protruding from the center has an outer diameter of 02 to 06 times the drill diameter, and part 7 has the same outer diameter as the drill diameter. Jl'+ also has a protruding cylindrical part 8, the side of 8 forms part of a conical shape, and the other end is a joint part 9 with a steel shaft, and its shape may be a circle of 3 m. Alternatively, the side view may be triangular.

Figure 4 shows a highly wear-resistant carbide tip with a cylindrical shape.
The center hole is designed to fit with the hole in Fig. 6, and the hole in the 4th
The joint surface with FIG. 10 has a shape of a circle z1 that fits with 7. Examples of the high toughness carbide tip in the present invention include J I SV5. The grade V6 is used, and fine-grained alloys are used as high wear-resistant carbide tips.

5KH-9 was used as the steel shank. The cemented carbide tips shown in FIGS. 6 and 4 may be joined by, for example, fitting the parts shown in FIG. 5 and the parts shown in FIG. 4 and then sintering them simultaneously. ``Add'': Post-sintered chips)
1(j) can also be obtained by drawing the parts shown in Figure 6.The tip of this main body has a length suitable for drilling IIX. 11. It has a small diameter of 1' degree, almost the same as J-mi, and has a chisel sword (-J) at its tip.

Furthermore, if necessary, measure the tip web thickness by
The grinding part to be removed is also subjected to IJ.

(E) Effect As explained below, the drill of the present invention is made of tough cemented carbide in the non-cutting part at the center where the cutting speed is slow, while the 1- mark is written on the outer periphery of the tip where the cutting speed is slow. Since it is made of cemented carbide, which has better wear resistance than cemented carbide, and the Le J shank, the characteristics of each material are fully exhibited, and it can withstand excessive thrust I and force. There is little chipping of I';' J, C1 deterioration on the outer circumferential cutting part, and the joining of the steel shank and Super 7 alloy by high speed rotation with strong thrust force, and no cracking due to the heat LL and force of '+Fli. This enables highly efficient machining with 1:11 speed rotation.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional carbide optical star drill, and FIG. 2 is a cross-sectional view of a carbide optical star drill obtained by the present invention. FIG. 6 shows a high-toughness carbide tip, and FIG. 4 shows a highly wear-resistant carbide tip. Figure 61 Valve Figure 2 Figure 45- Seri Figure 3

Claims (1)

[Scope of Claims] (1) High toughness carbide tip, high wear resistance of 19% (super hard tip and carbide tip made of steel). A carbide optical solid drill characterized by having a hard tip arranged therein and joining the high toughness carbide tip with a steel shank.Q) The diameter of the cylindrical protrusion of the high toughness carbide tip is 0 of the drill diameter.
The carbide optical star drill according to claim (1), characterized in that the hardness is in the range of 2 to 0.4 times. (6) The transverse rupture strength of the high-toughness carbide tip is 270 kg or more, and the transverse rupture strength of the highly wear-resistant tip is 270 ''.
/mx'rice (+:I:i),
;l'j The carbide optical star drill described in item (1).