JPS59173480A - Bit for excavation and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a drilling bit and a method for manufacturing the same.

[Prior art]

The following methods are generally used to manufacture the bit for the pedestal. That is, a cemented carbide cutting edge is planted in a carbon mold, skeleton powder for forming a hard surface portion is spread on the inner surface of the mold, and then skeleton powder for forming a matrix alloy portion is filled into the mold. Next, a molten binder alloy is infiltrated into this mold and the entire mold is sintered.

FIG. 1 is a cross-sectional view of the cutting edge of the bit manufactured in this way, and shows that the cemented carbide tip 10 is planted in the matrix alloy part 12. The surface is covered with a surface hardening portion (hard layer) 14. The hardened surface portion 14 and the matrix alloy portion 12 are constructed by bath-immersing the respective skeleton powders with a binder alloy.

However, in conventional bits manufactured in this manner, there is a tendency for the carbide tip to break when used for heavy-duty excavation, and there has been a problem in that the impact resistance is low.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, eliminate the fear of carbide tip breakage, and provide a drilling bit with excellent impact resistance and a method for manufacturing the same.

[Summary of the invention]

In order to achieve this object, the present invention has the following gist.

That is, the first invention provides a drilling bit in which a matrix alloy (two carbide tips) constituting the bit body are implanted, and the surface of the matrix alloy is coated with a hard layer. This drilling bit is characterized by a gap extending in the planting depth direction between the surface, the hard layer, and the matrix alloy.

A second invention is a drilling bit in which a carbide tip is embedded in a matrix alloy constituting a bit body, and the surface of the matrix alloy is coated with a hard layer, in which a laser beam is applied around the carbide tip. A method for manufacturing a drilling bit, characterized by HM a beam and forming a gap extending in the implantation depth direction between the side peripheral surface of the carbide tip, the hard layer, and the trix alloy. .

The present invention will be explained in more detail below.

FIG. 2 shows the vfr of the cutting edge of the bit according to the embodiment of the present invention.
It is a front view. In this embodiment, a gap 16 is formed between a surface hardening portion (hard layer) 14 on the peripheral surface of the carbide tip 10 and a matrix alloy portion 12 . Providing such a gap 16 reduces the shearing force acting on the chip and eliminates chipping. The reason for this is as follows (two guesses are made. Namely, as shown in Fig. 3, when a lateral load M is applied to the chip, the surface hardening part and the A reaction force F is applied to the tip as a reaction. By the way, when manufacturing bits, as explained in the prior art section above,
Infiltration method is used. In manufacturing based on this infiltration method, when the molten binder alloy is poured into the powder gap and solidified, the matrix alloy part 12 and the hard surface part 14 contract, and this contraction causes the cemented carbide chip to 1o
is tightly tightened and held. However, since the hardness of the surface hardening portion 14 is higher than that of the matrix alloy 12, when a load M (see FIG. 3) is applied to the carbide tip 10, the above-mentioned reaction force in the surface hardening portion 14 is generated. A large shearing force is generated at the tip of the chip 1o, and if this exceeds a predetermined limit, the chip will chip and break.

However, if the gap 16 is provided around the chip 1o as in the present invention, the lateral load M will be reduced to the chip 1o.
When , a reaction force F is exerted on the chip 10 from the surface layer.
Therefore, the shearing force generated on the chip 10 becomes small, and breakage is prevented.

Preferred values for @ and depth t of such a void 16 will now be described. First, as for the width t, as a result of intensive research by the inventors, it was found that a width of 40 to 400 μm is suitable. FIG. 4 is a graph showing an example of the results of this research, and is an example of the bending strength measured when a load M is applied to a large number of 6D chips of different types, sizes, etc. In this fourth figure, the value is 40 ~
When the difference from 400 μm is 80 to 320 μm (=,
It is clearly seen that it gives extremely excellent results.

Next, regarding the depth t, the value of t/L
It is preferable to set the distance to 80 inches. Figure 5 shows t
/ L x 100 (%) This is an example of measurement of bending strength when a load M is applied with various changes in the value. From FIG. 5, it is recognized that the preferable value is 30 to 85, or 40 to 80 (a).

The bit according to the first EA can be manufactured according to the method according to the twentieth invention. FIG. 6 is a sectional view showing an embodiment of the second invention.

That is, reference numeral 18 denotes a mold. After arranging the carbide chip 10 on the inner surface of the mold 18 and pasting skeleton powder 22 for forming a six-sided hardened part on the inner wall surface of the mold, a skeleton powder 24 for forming a matrix alloy part is attached. Fill it. Then, after pouring the molten metal from the runner 26 and solidifying it, the mold is demolded.
First, the bit is manufactured in an almost finished shape. Thereafter, as shown in FIG. 7, a laser beam 30 is irradiated around the carbide tip 10, and the side circumferential surface of the carbide tip 10, the surface hardening portion (hard layer) 14, and the MAF') Tx alloy portion 12 are irradiated around the carbide tip 10. A gap 16 extending in the planting depth direction is formed between the two. At this time, by selecting various conditions such as the intensity of the laser beam and the irradiation time, it is possible to form the gap 16 with a desired width and depth. 32 in FIG. 7 is a nozzle of a laser processing machine.

In this second invention, various types of skeleton powder for forming the hard layer can be used, including: 1. various hard metals (including alloys), hard metal carbides, and combinations of these; etc. are suitable. Specifically, for example,
Mixed powder of WC and co, W, WC, W2C, Cr
Examples include 5Cz. ``When adhering this hard powder to the inner surface of the mold, an adhesive such as a water-soluble polymer resin may be used.

Various metals (including alloys), metal carbides, metal/carbon composites, and combinations of these can be used as the skeleton powder for matrix alloy formation.
Furthermore, carbon may be added to these. For example, Fe, Ni, C,), W.

Carbon steel, stainless steel, p6*Mn6i, WC.

W2C, Cr3C2, TaC, TiC, VC, NbC, etc. can be used alone or in combination.

The binder alloy is preferably one that has a melting point lower than that of the skeleton powder, has excellent mechanical strength, wear resistance, and corrosion resistance, and has a small decrease in strength ρ at high temperatures. Specifically, Mn-Ni-Cu alloy, Mn-Ni-Cu-
8i alloy, aluminum bronze, high strength brass, Mn-
Co-Cu alloy, Mn-Ni-Cu-8
i-Li series alloy, Ni-8n-Cu series alloy,
Ni-8i alloy, Ni-Be alloy, Cu-Be alloy,
N1-B-8i-Fe-C alloy, P d -N i
-Mn alloy, Mn-Ni alloy, gold, Mn-Nj-
Co-based alloy, Ni-Cr-8i-based alloy, Mn-N i
Examples include -Cu-Co alloys.

Further, in the present invention, there are no restrictions on the shape, material, size, etc. of the carbide tip, and various shapes such as a button shape, a conical shape, and a chisel shape can be employed.

[Examples of the Invention] Example 1 An excavation pit was manufactured using the mold 18 shown in FIG. First, a cemented carbide tip 10 (made of WC-Co-based cemented carbide) was placed in a mold 18 . Next, W powder (particle size: 325 mesh or more, 20
0 mesh or less) and 50 parts by weight of WC powder (particle size: 300
A mixed powder of 50 parts by weight of 50 parts by weight of 150 or more meshes was used, and this was adhered to the inner wall surface 2o of the mold 18. In addition, at the time of this pasting, a small amount of adhesive made of water-soluble polymer resin was applied.

Next, a mixed powder of 85 parts by weight of Fe powder (particle size: 100 mesh or less) and 15 parts by weight of Ni powder (particle size: 200 mesh or less) was charged into the mold 18 as a skeleton powder for forming the matrix joint ζ part. . Thereafter, the molten binder alloy was poured into the mold 18 through the runner 26, cooled, and solidified. The composition of the binder alloy is
Mn is 25 wt%, Ni is 15 wt%, and Cu is 60 wt%.

Thereafter, the mold 18 was demolded, and the contents, ie, the pit in the shape of an almost finished product, were taken out. Then, a laser beam of 3° was irradiated around the carbide tip 1o to form a gap 16. By changing the intensity, depth of focus, and irradiation time of the laser beam! ,? , diameter d = 1' 2 w
n, planting depth L = 9 tax.

For the thus manufactured pit having the cutting edge portion as shown in FIG. 2, a load M as shown in FIG. 3 was applied to the carbide tip 10, and the bending strength until breakage was measured.

An example of the results is shown in FIGS. 4 and 5.

In FIG. 4, the depth L of the gap 16 is constant at 6 m, and the width t is 0 to 500 μm (t/d×100 (tl;
) and 0 to 4.2%) are shown.

In Fig. 5, the width of the gap 160 is constant, t = 200 μm;
Its depth t is in the range of 0 to 9 gourds (t/L xio
The bending strength is shown when changing O (%) from θ to 100%). In addition, the hardness (HRB) of the matrix alloy part
was 88-4, and the hardness (HRC) of the hard surface portion was 34.0.

Example 2 Fe as skeleton powder for forming matrix alloy part
A mixed powder of 70 parts by weight of powder (particle size: 100 mesh or less) and co powder (particle size: 100 mesh or less, 325 mesh or more) was used, and Mn was used as a binder alloy.
A test was conducted in the same manner as in Example 1 except that 40 wt% Ni, 30 wt% Ni, and 30 w.1% Cu was used, and the same results as in Example 1 were obtained. The hardness (HRB) of the matrix alloy part was 95.2, and the hardness (HRC) of the hard surface part was 42.7.

A rock excavation test was conducted using a tricone pit (7T inch, IJ-10 metal insert type tricone pit) equipped with a pit manufactured according to Example 1. The excavation speed was determined by varying the pit load. The results are shown in FIG. The pit rotation speed was 50R, P, M, and fresh water was used for water supply, with a water flow rate of 800A/min. The rocks are Kofu andesite and Enzan Hananite.

As a comparative example, a similar excavation test was conducted using a conventional tricone pit (configured as shown in Figure 1). , the results are also shown in FIG. As shown in FIG. 8, it can be seen that the product of the present invention has excellent excavability in the high bit load region where strong impact is applied, compared to the conventional product.

〔Effect of the invention〕

As stated above, according to the present invention, it is possible to obtain an excavation pit with excellent impact resistance and no fear of chipping of the carbide chips.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional pit cutting edge, Fig. 2 is a sectional view of a pit cutting edge according to an embodiment of the present invention, Fig. 3 is a diagram showing external force applied to the chip, and Fig. 4 is a soft layer. FIG. 5 is a graph showing the relationship between the depth of the soft layer and chip bending strength. FIG. 6 is a cross-sectional view of a mold showing the manufacturing method of the present invention. FIG. 8 is a cross-sectional view of the cutting edge during laser irradiation, showing the manufacturing method of the present invention.
The figure is a graph showing the relationship between bit load and excavation speed. 10... Carbide tip, 12... Matrix alloy,
14... Surface hardening part (hard layer), 16... Gap, 1
8.: Mold, 30. Loser Beam. Figure 6 Figure 7 Figure 8

Claims (2)

[Claims] (1) In a drilling bit in which a carbide tip is not embedded in the matrix alloy constituting the bit body and the surface of the matrix alloy is coated with a hard layer, the side peripheral surface of the carbide tip and the hard layer A drilling bit characterized in that a gap extending in the planting depth direction is formed between the layer and the matrix alloy. (2) Matrix alloy (=
In drilling bits whose surface is coated with a hard layer of IJTx alloy,
Drilling characterized by irradiating the periphery of the carbide tip with a laser beam to form a gap extending in the implantation depth direction between the side peripheral surface of the carbide tip and the hard layer and the trix alloy. Method of manufacturing bits for use.