JP2010112120A - Excavating bit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-temperature resistant excavating bit with a safe carbide tip causing no separation phenomenon caused by melting of a brazed section of a sheath pipe (a sleeve) and the carbide tip due to a high temperature, nor causing a crack/deterioration by welding with a metal base and consequent separation from the metal base. <P>SOLUTION: The excavating bit is formed by fitting the inner peripheral surface of a steel sheath pipe 11 to the carbide tip 10 constituted by forming a tip part 10' in almost conical shape and a body part 10" in cylindrical shape, over the outer peripheral surface of the body part 10" from a middle peripheral surface 10a of the tip part 10', engaging the middle peripheral surface 10a with a tip part inclined inner peripheral surface 11a of the sheath pipe 11, brazing the fitted and engaged portions to integrate the carbide tip 10 with the sheath pipe 11, fitting and supporting the carbide tip 10 into a bottomed hole 9 bored in the tip surfaces 3', 3" of the steel metal base 3 through the sheath pipe 11, and welding the sheath pipe 11 and the metal base 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an excavation bit attached to the tip of a rod of a rock drill used at a high temperature at a blast furnace outlet or a steel outlet of a converter.

  Conventionally, a mud material that closes the outlet of the blast furnace is drilled to form an opening to discharge the hot metal, and the outlet is closed again with the mud material.

  By repeating the above operation, hot metal, slag, etc. adhere to the spout and the spout is blocked except for the mud material, and the discharge of the hot metal becomes worse.

  In addition, the hot metal or the like infiltrated into the mud material itself, the mud material deteriorated, the outlet of the mud material was not sufficiently blocked, and the hot metal leaked.

  In this state, it is necessary to perform repair work on the spout, such as periodically removing slag and molten iron adhering to the spout and closing the spout with new mud material. A carbide tip is supported through a steel sleeve (fixing member) in a bottomed hole drilled in the tip surface of a steel base of a drilling bit attached to the tip of a rotatable rod, and the base and The above-mentioned sleeve is fixed by welding, and the cemented carbide tip and the steel sleeve are fixed to one body by brazing (brass) for high temperature, for example (Patent Document 1).

  However, the inner peripheral surface of the steel sleeve is a cylindrical body having the same diameter from the tip opening to the bottom, and the cylindrical body of the carbide tip is fitted into the sleeve from the tip opening to the bottom. The inner peripheral surface of the sleeve is fitted with the same diameter as the outer peripheral surface of the cemented carbide chip, and the fitting surface is brazed with copper brazing. The wax eluted from the opening of the sleeve. Therefore, there is a problem that the cemented carbide tip is easily separated from the sleeve.

  That is, there was a serious defect that the cemented carbide tip was easily released from the sleeve welded to the base metal due to melting of brazing.

  In addition, an excavation bit in which a cemented carbide tip is directly planted in a bottomed hole formed in the base metal and the chip and the base metal are directly fixed by welding is recognized (Patent Document 2, FIG. 8).

  Such a cemented carbide tip has a problem that it is easily affected by the welding temperature and easily cracks or changes in quality and is easily separated from the base metal.

  In addition, a tip hole having a diameter larger than the outer diameter of the carbide tip is provided on the surface of the steel base metal, and the base of the substantially conical carbide tip is fitted into the tip hole, and the outer diameter is the inner diameter of the tip hole. In a state where a presser plate having a through hole that engages in the middle of the cemented carbide tip is fitted in the center of the chip hole, and the outer peripheral surface of the cemented carbide chip is pressed by the inner peripheral surface of the through hole. The outer periphery of the presser plate was welded and fixed to the peripheral edge of the tip hole (Patent Document 3).

  In order to support the presser plate in a state where the conical inclined surface of the carbide tip in the central part is pressed by the inner peripheral surface of the through hole in the central part, an appropriate gap is provided between the inner surface of the chip hole and the outer peripheral surface of the chip. Since the air in the gap needs to be expanded, it is necessary to drill an unwelded portion or a thin through hole for air circulation (Patent Document 3, paragraphs “0011” and “0013”). ).

JP 2006-328881 A JP 2007-131874 A JP 2006-289549 A

  In the present invention, there is no separation phenomenon due to melting of the brazed portion between the sheath tube (sleeve) and the cemented carbide tip due to high temperature, and there is no crack or alteration due to welding with the base metal, and no separation from the base metal. The purpose is to obtain a high-temperature drilling bit with a carbide tip easily and quickly.

In order to achieve the above object, the present invention provides a cemented carbide chip in which a tip portion is substantially conical and a body portion is formed in a cylindrical shape. The inner peripheral surface of the steel sheath tube is fitted over the surface, the intermediate outer peripheral surface is engaged with the inclined inner peripheral surface of the distal end portion of the sheath tube, and the fitting and engaging portions are brazed. The cemented carbide tip and the sheath tube are combined into one body, and the cemented carbide tip is fitted and supported in a bottomed hole formed in the distal end surface of the steel base metal through the sheath tube, and the sheath A drilling bit formed by welding a tube and the above base metal,
Second, the drill bit according to the first invention, wherein the outer peripheral surface of the sheath tube is cylindrical and the height thereof is greater than the depth of the bottomed hole,
Third, the tip center portion of the cemented carbide tip protrudes from the tip opening of the sheath tube, and the sheath tube and the other end of the tip are supported by the bottom surface of the bottomed hole. Drill bit,
4thly, the excavation bit in any one of the said 1st-3rd invention in which the front end surface of the said steel base metal consists of a large diameter front end surface and the small diameter front end surface which protruded on the common centerline in the center part ,
Consists of.

  Therefore, a drill bit formed by connecting a base metal to the tip of the drill rod (FIG. 7) and projecting a plurality of cemented carbide tips on the tip surface of the base metal is directed toward the hot outlet or steel outlet. It is possible to crush the tap mouth or the inner sleeve brick or mud material of the tap mouth by rotating and hitting with a drill from the tip of the bit.

  At that time, the tip of the carbide tip supported by the base of the excavation bit is not likely to come out of the sheath tube by engaging the inner peripheral surface of the distal end portion of the sheath tube, and the sheath tube has a thick tip portion. The tip portion is securely held by the base metal, and the crushing correction of the mud material of the tap port or the tap steel port or the inner sleeve brick is performed without any trouble.

  Since the present invention is configured as described above, there is no risk that the tip of the cemented carbide tip is hooked on the tip of the sheath tube and is separated from the sheath tube fixedly welded to the base metal. In addition, there is an effect that a safe and easy-to-weld excavation bit of a steel tap or a steel tap is easily obtained. In addition, there is an effect that excavation can be performed safely and accurately by leading the small-diameter tip surface of the bit in advance.

  A rock drill (not shown) is provided with a rotary hammering excavation rod 1, and a steel base metal 3 of an excavation bit 2 is provided at the tip of the rod 1 by flanges 4, 4, bolts 5 or screw fastening.

  The steel base metal 3 is composed of a two-stage tip surface 3 ′, 3 ″, and the central small-diameter tip surface 3 ″ protrudes on the common center line c at the center of the large-diameter tip surface 3 ′. The side surface 6 is inserted into the inner periphery of the mud material or sleeve brick 8 remaining on the peripheral surface of the tap hole or the steel tap port 7 (FIG. 7), and the propulsion by the excavation bit 2 can be guided.

  A plurality of bottomed holes 9 are formed in the front end surfaces 3 ′ and 3 ″ of the base metal 3, and a cemented carbide chip 10 made of cemented carbide is inserted into each bottomed hole 9 through a steel sheath tube 11. And support.

The cemented carbide tip 10 has a tip portion 10 'formed in a substantially conical shape and a body portion 10 "formed in a cylindrical shape.
The inner peripheral surface of the steel sheath tube 11 is fitted from the middle inclined outer peripheral surface 10a of the tip portion 10 'to the cylindrical outer peripheral surface 10b of the main body portion 10'',
The intermediate inclined outer peripheral surface 10a and the tip end inclined inner peripheral surface 11a of the sheath tube 11 are engaged with and fitted to each other (see FIG. 2 (a)).

  In the above engagement and fitting, in a state in which molten brass having a melting point of about 1080 ° C. is injected and supplied to the inner surface of the sheath tube 11 shown in FIG. 1 (a), the cemented carbide (tungsten carbide) shown in FIG. As shown in FIG. 2 (a), the cemented carbide chip 10 is fitted and cooled, and brass brazing 12 is performed in the gap between the engagement and the fitting part (about 0.2 mm). And the sheath tube 11 can be made into one body.

  Thereafter, the tip 10 and the sheath tube 11 shown in FIG. 2 (a) are fitted into the bottomed hole 9 shown in FIG. 2 (b) through a gap s of about 0.1 mm.

  The outer peripheral surface of the sheath tube 11 is cylindrical, and its height is larger than the depth of the bottomed hole 9 as shown in FIG. 3, and it protrudes 11b from the tip surfaces 3 'and 3' '(FIG. 3).

  The inner peripheral surface 11a of the protruding portion 11b is fitted and engaged with the outer peripheral surface 10a of the substantially conical tip of the tip 10, and since the outer peripheral surface of the protruding portion 11b is cylindrical, the thickness t is The tip is larger.

  Then, the protruding portion 11 b and the tip end surfaces 3 ′, 3 ″ of the base metal 3 are welded by electric welding 13.

  In this state, the tip center portion 10 c of the tip 10 protrudes from the weld 13 by the welding and the tip opening of the sheath tube 11.

  The above-mentioned large and small diameters of the steel base metal 3 of the excavation bit 2 that is detachably provided at the tip of the rotary hammering excavation rod 1 attached to the excavator (drill) facing the outlet of the blast furnace or the outlet of the converter. The tip 13 is welded 13 through the steel sheath tube 11 and is fitted and engaged with the inner peripheral surface of the sheath tube 11, and the cemented carbide tip 10 is fixed by brazing 12. The drill bit 2 can be formed.

  This excavation bit 2 can enter into the tap hole or the tap hole 7 by rotational impact, and the opening or inner sleeve brick 8 or the mud material can be crushed (FIG. 7).

  In this state, the middle inclined outer peripheral surface 10 a of the tip portion 10 ′ of the cemented carbide tip 10 is hooked and engaged with the tip inner inclined inner peripheral surface 11 a of the sheath tube 11, so that the tip 10 is in the sheath tube 11. There is no risk of sliding inside the casing tube 11, there is no risk of separation from the sheath tube 11, and the tip 10 is not released from the distal end surface 3 ′, 3 ″ of the base metal 3. The rotation hitting propulsion or backward movement of the bit 2 in the steel port 7 is performed safely.

(A) is a longitudinal sectional view of a sheath tube, (b) is a front view of a cemented carbide bit, and (c) is a longitudinal sectional view of a bottomed hole. (A) The figure is a longitudinal cross-sectional view of the brazed state of the cemented carbide bit and the sheath tube, and (b) is a longitudinal cross-sectional view of the bottomed hole. It is a longitudinal cross-sectional view of a state in which a sheath tube is fitted into a bottomed hole of a base metal and bonded to the base metal. It is an expansion perspective view of a drill bit. It is a top view of the excavation bit of the present invention. It is a top view which shows arrangement | positioning of the carbide tip in the said excavation bit. FIG. 7 is a front view of FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation impact drilling rod 2 Drilling bit 3 Steel base metal 3 ', 3 "Tip surface 6 Side surface 7 Mouth or outlet 8 Sleeve brick 9 Bottom hole 10 Carbide tip 10' Tip 10" Main part 10a Middle inclined outer peripheral surface 10b Cylindrical outer peripheral surface 11 Steel sheath tube 11a Tip inclined inner peripheral surface 11b Protruding portion 12 Brass brazing 13 Welding t Thickness

Claims (4)

To the carbide tip formed by forming the tip part into a substantially conical shape and the body part into a cylindrical shape,
The inner peripheral surface of the steel sheath tube is fitted over the outer peripheral surface of the main body portion from the intermediate outer peripheral surface of the distal end portion, and the intermediate outer peripheral surface and the inclined inner peripheral surface of the distal end portion of the sheath tube Engage
Brazing the fitting and engaging part to make the carbide tip and the sheath tube into one body,
An excavation bit formed by fitting and supporting the cemented carbide tip in a bottomed hole formed in a tip end surface of a steel base metal through the sheath tube, and welding the sheath tube and the base metal.   The excavation bit according to claim 1, wherein the outer peripheral surface of the sheath tube is cylindrical, and the height thereof is greater than the depth of the bottomed hole.   The excavation bit according to claim 1 or 2, wherein a tip center portion of the cemented carbide tip protrudes from a tip opening of the sheath tube, and the other end of the sheath tube and the tip is supported by a bottom surface of the bottomed hole.   The excavation bit according to any one of claims 1 to 3, wherein the tip surface of the steel base metal includes a large-diameter tip surface and a small-diameter tip surface protruding on a common center line at a central portion thereof.

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