JP2005230888A - Manufacturing method of excavating tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an excavating tool, which can efficiently produce the excavating tool with an excavating bit made of cemented carbide. <P>SOLUTION: A rod-like intermediate member to connect an excavating bit member made of cemented carbide with a shank member made of steel, and the shank member made of steel are bonded utilizing friction heat generated by forcibly pressing them coaxially while one member is rotated and the other is fixed. Then a composite member thus obtained and the excavating bit member made of cemented carbide are similarly friction-bonded to compose the excavating tool material, and then subjected to a surface treatment to complete the excavating tool. An Fe-Ni-Co alloy is desirable for the intermediate member material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a tool having a drill bit made of cemented carbide and suitable for tunnel excavation.

Conventionally, a conical bit having a tip portion made of cemented carbide is used for a round bit which is a cutting edge of an excavator used for tunnel excavation or the like.
This conical bit is manufactured by joining a carbide bit to a tip of a steel material shank portion by press-fitting or brazing into a shank hole. In this case, the carbide bit falls off due to impact or the shank wears quickly. As a factor, the adhesion between the carbide bit and the steel shank is poor, the hardness of the shank is limited due to brazing, and the wear resistance is lacking. In addition, the length of the cemented carbide part for brazing, cleaning, drilling, heat source, etc. will be expensive.

  A drill bit made of cemented carbide and a steel shank member are prepared and the drill bit is made of cemented carbide and the shank portion is made of steel. A method is widely used in which a bit member and a shank member are joined by brazing or press-fitting, and then an excavation tool is formed, followed by heat treatment and grinding.

A conventional method for manufacturing a drill bit will be described in more detail. Conventional cemented carbide brazing operations were performed as follows.
First, in order to join a cemented carbide that is a cutting edge of a bit and a steel shank that is a support, a brazing operation is performed by straight or tapered holes. Next, the cemented carbide and steel shank to be brazed are thoroughly cleaned using a solvent, and the brazing material and a special flux are applied. Thereafter, it is fixed with copper or silver solder, and heated in a heating furnace (electric furnace, coke oven, gas burner, high frequency, etc.). When the wax melts and spreads across the surface, stop heating and move the cemented carbide with a thin rod, or tap it lightly, then fix and press at a normal position and wait for the wax to harden. The thickness of the wax is as thin as possible, and after each wax is made to rotate uniformly, it is gradually cooled using lime wood ash or the like. In order to complete the bonding, copper brazing and silver brazing may be double brazed.
However, in the conventional brazing operation, even if it takes time and effort in this way, the cemented carbide often tends to crack due to the residual stress generated when brazing the cemented carbide and the steel shank. There are serious difficulties other than processing costs. Further, this method cannot increase the hardness of the steel material, is easily worn out, and may fall off because it is vulnerable to impact.

  In the conventional method of manufacturing a bit by brazing or press-fitting, a brazing material is arranged between the bit member and the shank member, and the harmful solvent cleaning and heating device, and the bit is 2 to 3 times the outer diameter. Length is needed. In particular, conventional products wear quickly and are often used while being welded. The processing cost, material cost, wear resistance, etc. were all problems.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a drill bit having a bit portion made of cemented carbide that is efficient and highly reliable.

  The present invention makes the carbide bit part an umbrella shape of about 1/3 length, eliminates the hole processing of the shank part, reduces the cost by solid phase diffusion bonding, and further, the outer periphery is hardened by this joining technique. Focusing on the fact that it can soften and produce ideal round bits with high impact resistance, and the surface hardness of steel shanks can reach the limit of quenching, and it is completed with the knowledge that it has outstanding wear resistance It is a thing.

Another manufacturing method of the excavation bit of the present invention is for joining a steel rod-shaped shank member having a tip surface extending so as to be substantially orthogonal to the axial direction and a rear end surface extending so as to be substantially orthogonal to the axial direction. Preparing each of the rod-shaped intermediate member, rotating one of the shank member and the intermediate member, fixing the other, and pressing the front end surface of the shank member and the rear end surface of the intermediate member To generate frictional heat sufficient to soften the front end of the shank member and the rear end of the intermediate member between the shank member and the intermediate member, and the frictional heat causes the Stop the rotation of the shank member or intermediate member and apply pressure to bring the front end surface of the shank member and the rear end surface of the intermediate member into pressure contact with each other. And bonding the bets,
Preparing the obtained composite member and a cemented carbide umbrella-shaped bit, rotating one of the member and the bit member and fixing the other, and concentrating the intermediate member side of the composite member Friction heat sufficient to soften the front end surface processed into a bit and the rear end surface of the bit member is generated, and the intermediate material front end portion of the composite member and the rear end portion of the bit member are sufficiently generated by the friction heat. When softened, the rotation of the composite member or the bit member is stopped, pressure is applied to press the intermediate material front end surface of the composite member and the rear end surface of the bit member, and the composite member and the bit member , And the obtained excavation bit member is slowly cooled at a low temperature to produce an excavation tool comprising the excavation bit and a steel shank material bonded to the excavation bit.
Thereafter, necessary processing such as surface coating and surface polishing can be performed.

  In the present invention, it is important that the shank composite member and the bit are friction-welded and then cooled sufficiently at a low temperature.

  According to this method, even when a cemented carbide umbrella bit member and a steel rod-shaped shank member with a large difference in thermal expansion coefficient are used, excavation is excellent in pressure resistance and wear resistance without damage due to cracks, etc. Round bits can be manufactured.

  As described above, according to the present invention, an excavation tool having a cemented carbide bit portion on the tip side can be efficiently manufactured without breakage due to cracks or the like during the process. The joining strength between the alloy excavation bit member and the steel shank member can be considerably increased as compared with the joining by brazing.

[Drilling tools]
First, as shown in FIG. 1 which is a front view of the conical bit of the present invention, a shank material 52 having a gripping portion 53 formed of steel or the like, and a bit body coupled to the tip portion of the conical bit It consists of a cutting edge 51 made of hard alloy. And this shank material and the blade edge | tip part are joined by the very thin intermediate material 54. FIG. Details of the intermediate material will be described later.

[Drilling tool manufacturing method]
Hereinafter, a method for manufacturing the excavation tool will be described.

(Join using intermediate material)
This embodiment shows an example in which a cemented carbide bit member and a steel shank member are joined using an intermediate material. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  2-6 is a figure which illustrates notionally the process of the manufacturing method of the excavation tool in connection with this invention.

  In order to carry out the manufacturing method of the excavation bit, here, a rotary pinch device (chuck) 3 attached to the tip of the rotary shaft 1 and a rotary pinch device 3 on the clamp table 5 in a direction to be in contact with and away from the rotary pinch device 3 are used. And a friction welding mechanism 9 including a non-rotating pinching device (vise) 7 that is coaxially mounted.

  First, a rod-shaped intermediate member 25 having an appropriate diameter and length, and a steel shank member 13 having an appropriate length and shape that is substantially the same diameter as the intermediate member 25 are prepared. 25 is clamped by the rotary pinch device 3 and fixed to the rotary shaft 1 side, and the shank member 13 is pinched by the non-rotary pinch device 7 and fixed to the clamp base 5 side (FIG. 2).

  In this state, the rotation shaft 1 is rotated to rotate the intermediate member 25, and the intermediate member 25 is slid to the clamp base 5 side, and the tip of the shank member 13 is placed on the rear end surface 27 of the intermediate member 25. The surface 17 is pressed concentrically to generate frictional heat with the intermediate member 13. (FIG. 3) Since both the rear end surface 27 of the intermediate member 25 and the front end surface 17 of the shank member 13 are formed so as to extend substantially orthogonal to the axial direction, the rear end surface 27 of the intermediate member 25 is formed. Thus, the tip member 17 rotates with the shank member 13 in full contact with the tip end surface 17.

  In the process of generating frictional heat, the rotational speed of the rotary shaft 1 is kept constant, but the pressing force between the rear end surface 27 of the intermediate member and the front end surface 17 of the shank member 13 due to the pressing of the clamp base 5 is It is comprised so that it may become large gradually. The number of rotations of the rotating shaft 1 that is maintained constant is selected within a range of 1000 to 10,000 rotations per minute.

  When the front end portion 17 of the shank member 13 and the rear end portion of the intermediate member 25 are sufficiently softened by the frictional heat generated between the intermediate member 25 and the shank member 13, the rotation of the rotary shaft 1 is caused. A so-called secondary pressurization (upset pressurization) for increasing the pressing force by the clamp base 5 is performed suddenly, and the front end surface 17 of the shank member 13 is strongly pressed against the rear end surface 27 of the intermediate member 25. As a result, the rear end portion 27 of the intermediate member 25 and the front end portion of the shank member 13 are sufficiently plastically deformed and joined (FIG. 3).

  In this step, the rear end surface 27 of the intermediate member 25 and the front end surface 17 of the shank member 13 rotate in a state where they are in full contact with each other, so that the rear end portion of the intermediate member 25 and the shank member 13 are rotated. The front end portion is heated to the required temperature entirely or entirely in a short time and is sufficiently softened, and thus becomes solid by solid phase diffusion bonding between the intermediate member 25 and the shank member 13. After the secondary pressurization, the composite member 31 formed by the obtained intermediate member 25 and the shank member 13 is housed in a furnace, subjected to low-temperature slow cooling, and the generated burrs are cut and processed. The shank member 31 is used. The thickness of the intermediate member 25 is preferably 0 to 1.0 mm. For this purpose, when the composite shank member 31 is friction-welded with the cemented carbide bit member, Cutting for cost and prevention of micro-vibration.

  Next, the composite shank member 31 formed by the intermediate member 25 and the shank member 13 obtained in this manner is sandwiched by the rotational clamping device (chuck) 3 and fixed to the rotary shaft 1 side, while the carbide The non-rotating pinching device 7 (collet chuck) is sandwiched and fixed to the clamp table 5 side so that the end portion on the alloy bit member 11 side is close to the rotating shaft 1 side (FIG. 4).

  In this state, the rotary shaft 1 is rotated to rotate the composite shank member 31, and the cemented carbide bit 11 is slid on the clamp base 5, so that the front end surface of the composite shank member 31 is placed on the rear end surface 15 of the bit 11. 29 is pressed concentrically to generate frictional heat between the bit member 11 and the composite shank member 31 (FIG. 5). Since both the rear end surface 15 of the bit member 11 and the front end surface 29 of the composite shank member 31 are formed so as to extend substantially perpendicular to the axial direction, the rear end surface 15 of the bit member 11 and the composite shank member 31 The tip end surface 29 rotates while being in full contact.

  In the process of generating frictional heat, the rotational speed of the rotary shaft 1 is kept constant, but the pressing force between the rear end surface 15 of the bit member 11 and the front end surface 29 of the composite shank member 31 due to the pressing of the clamp base 5 is It is comprised so that it may become large gradually. The number of rotations of the rotating shaft 1 that is maintained constant is selected within a range of 1000 to 10,000 rotations per minute.

  When the front end portion of the composite shank member 31 and the rear end portion of the bit member 11 are sufficiently softened by frictional heat generated between the bit member 11 and the composite shank member 31, the rotation shaft 1 is rotated. A so-called secondary pressurization (upset pressurization) for increasing the pressing force by the slide member 5 is performed suddenly, and the front end surface 29 of the composite shank member 31 is pressed strongly against the rear end surface 15 of the bit member 11. As a result, the rear end portion of the bit member 11 and the front end portion of the composite shank member 31 are sufficiently plastically deformed and solid phase diffusion bonded (FIG. 5).

In this step, the rear end surface 15 of the bit member 11 and the front end surface 29 of the composite member 31 rotate in a state where they are in full contact with each other, so that the rear end portion of the bit member 11 and the front end portion of the composite member 31 are rotated. Is heated to a necessary temperature over the entire surface or the entire surface in a short time and sufficiently softened, so that the bonding between the bit member 11 and the composite member 31 becomes strong.
After the secondary processing, the axial dimension is determined, and when joining is completed, low-temperature slow cooling is performed in the furnace, and the generated burrs are cut to manufacture a drilling bit.

  Next, the excavation bit member 19 formed by joining the bit member 11 and the composite member 31 is removed from the friction welding mechanism 9, and the surface treatment necessary for the excavation bit member 19 is performed, and the excavation round bit 23 Is manufactured (FIG. 6).

  As the intermediate material used in this embodiment, an iron-nickel-cobalt alloy is suitable. The ratio of these constituent elements is composed of nickel 25 to 40% by weight, cobalt 15 to 30% by weight and the balance iron, specifically, nickel 29% by weight called cobalt, 17% by weight cobalt. And what consists mainly of remainder iron is preferable. This alloy may inevitably contain a small amount of carbon, silicon, manganese or the like.

  This intermediate material is preferably present in the range of about 0 to 1 mm in the finally produced round bit for excavation, and preferably 0.05 to 0.10 mm. When the length of the intermediate material is 1 mm or more, the bonding strength may be weakened. However, it is most important to select an intermediate material according to the components of the cemented carbide to be joined and the components of the steel material for shank.

In the above description, the example in which the obtained composite member and the cemented carbide member are joined after joining the shank member and the intermediate member is shown. After the member and the intermediate member are joined, the shank member may be joined.

It is a front view of the excavation tool of the present invention. It is a figure which illustrates notionally the process of the manufacturing method of the excavation tool concerning this invention, and is a figure which shows the state which attached the member for intermediate materials, and the member for shank to the friction welding mechanism. It is a figure which illustrates notionally the process of the manufacturing method of the excavation tool in connection with this invention, generate | occur | produces friction heat between the member for intermediate materials, and the member for shank, and is used for the rear-end part of a member for intermediate materials, and a shank It is a figure which shows the process of joining the front-end | tip part of a member. It is a figure which illustrates notionally the process of the manufacturing method of the excavation tool concerning this invention, and is the figure which shows the state which attached the composite member which consists of the member for intermediate | middle materials and the member for shank, and the member made from a cemented carbide to the friction welding mechanism. It is. It is a figure which illustrates notionally the process of the manufacturing method of the excavation tool concerning this invention, and the process of generating friction heat between the composite member which consists of the member for intermediate | middle materials and the member for shank, and the member made from a cemented carbide. FIG. It is a figure which illustrates notionally the process of the manufacturing method of the excavation tool concerning this invention, and is the figure which shows the state which joined the member for excavation, and the composite member which the intermediate member and the front-end | tip part of the member for shank joined. is there.

Explanation of symbols

1 Rotating shaft
3 Rotary pinching device
5 Clamp stand
7 Non-rotating pinching device
DESCRIPTION OF SYMBOLS 9 Friction welding mechanism 11 Excavation member 13 Shank member 15 Rear end surface of excavation member 17 Front end surface of shank member 19 Excavation tool material 21 Excavation bit 23 Excavation tool 25 Intermediate material member 27 Rear end surface of intermediate material member 29 Composite member-side front end surface 31 Composite member of intermediate member and shank member 51 Cutting edge portion 52 Shank member 53 Holding portion 54 Intermediate material

Claims (5)

A method of manufacturing a bit in which a drilling bit portion is formed on the tip side, and a steel rod-shaped shank member having a tip surface extending so as to be substantially orthogonal to the axial direction, and after spreading so as to be substantially orthogonal to the axial direction A step of preparing a rod-shaped member of a joining intermediate material having end faces,
One of the shank member and the intermediate member rod-like member is rotated, the other is fixed, and the front end surface of the shank member and the rear end surface of the intermediate member are pressed against each other. Generating a frictional heat sufficient to soften a tip portion of the shank member and a rear end portion of the excavation bit member between a member and the intermediate member;
When the front end of the shank member and the rear end of the intermediate member are sufficiently softened by the frictional heat, the front end surface of the shank member and the rear end surface of the intermediate member Forming a composite member by pressure-contacting the shank member and the intermediate material member;
A step of preparing the composite member obtained by the above-described step and a cemented carbide conical bit;
One of the composite member and the excavation bit is rotated, the other is fixed, and the intermediate member-side front end surface of the composite member and the rear end surface of the excavation bit are pressed, Generating frictional heat sufficient to soften the front end portion of the composite member and the rear end portion of the excavation bit between the excavation bit;
When the intermediate material front end portion of the composite member and the rear end portion of the excavation bit are sufficiently softened by the frictional heat, the intermediate material front end surface of the composite member and the rear end surface of the excavation bit Forming a tool material for excavation by joining the composite material and the excavation bit by pressure welding,
And a step of slowly cooling the excavation tool material at a low temperature.   The method for manufacturing an excavation tool according to claim 1, wherein the composite member formed by joining the shank member and the intermediate member is further cooled at a low temperature.   The method for manufacturing an excavating tool according to claim 1, wherein the intermediate material is an iron-nickel-cobalt alloy.   The composition of the iron-nickel-cobalt alloy which is the said intermediate material consists of nickel 29-34 mass%, cobalt 17-22 mass%, and the remainder iron, The excavation tool of Claim 3 characterized by the above-mentioned. Manufacturing method. After joining the intermediate material and the shank member, the axial length of the intermediate material is adjusted to be 0 to 1 mm, and then a cemented carbide bit is joined to the end of the intermediate material. The manufacturing method of the excavation tool of Claim 4.

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