阅读说明：本技术 开孔钻头以及使用其的出铁口的开孔方法 (Tapping drill and tapping method using same ) 是由 北村洋平 河上智彦 堀之内恒平 于 2020-03-10 设计创作，主要内容包括：提出开孔钻头以及使用其的出铁口的开孔方法,通过对高炉炉底部高效地进行升温、从而能够在比较短时间内进行长时间停风后的启动和/或炉冷事故后的启动,并能够简化用于设置炉底部升温用燃烧器喷枪的出铁口的开孔作业。开孔钻头1,用于对高炉炉底的出铁口进行开孔,在开孔钻头的炉内挖掘面1a的背面1b、1c具有突片2,就突片而言,突片的最外侧端部位于比开孔钻头的最外侧端部靠内侧的位置。(Provided are a drill for tapping and a method for tapping a tap hole using the same, which can efficiently raise the temperature of the bottom of a blast furnace, can perform start-up after a long-time air cut-off and/or start-up after a furnace cold accident in a relatively short time, and can simplify the tapping work for installing the tap hole of a burner lance for raising the temperature of the furnace bottom. A hole drill 1 for drilling a tap hole in a blast furnace bottom, wherein projecting pieces 2 are provided on rear surfaces 1b and 1c of an excavation surface 1a in a furnace of the hole drill, and outermost end portions of the projecting pieces are positioned inward of outermost end portions of the hole drill.)

1. And a hole drill for drilling a tap hole in a blast furnace bottom, wherein a protruding piece is provided on a rear surface of an in-furnace excavation surface of the hole drill, and an outermost end of the protruding piece is located inward of an outermost end of the hole drill.

2. The open hole drill according to claim 1, which is an open hole drill for opening a tap hole in a blast furnace bottom, the open hole drill being used for opening a hole in the tap hole for installing a burner lance for raising the temperature of the furnace bottom.

3. A method for forming a tap hole, comprising forming a hole for installing a burner lance for raising the temperature of a blast furnace bottom in the tap hole of the blast furnace bottom, wherein the tap hole is formed by using a tapping machine provided with the tapping drill according to claim 2.

Technical Field

The present invention relates to a boring bit for boring a taphole of a blast furnace or the like, and particularly to a boring bit for boring a hole for installing a burner lance used at the time of stopping the blast furnace or the like in the taphole, and a method for boring a taphole using the boring bit.

Background

The blast furnace is the following equipment: the temperature of iron ore is raised, reduced, and melted by high-temperature air and high-temperature reducing gas generated by the reaction of oxygen with coke and fine carbon blown from the tuyere portion, and pig iron and slag are produced from an iron outlet provided at a lower portion of the tuyere portion. In the normal operation of the blast furnace, the reaction heat in the furnace is balanced with the heat supply from the tuyere, and therefore, the stable operation of the blast furnace can be performed. However, sometimes, due to an operation failure and/or equipment failure of the blast furnace, production adjustment, it is necessary to stop the supply of air to the blast furnace. In addition, the blast furnace may need to be stopped for a long time due to maintenance work due to the deterioration of the blast furnace. During the period of stopping wind, the secondary furnace body_·The temperature of the charge and the melt in the furnace (hereinafter referred to as furnace temperature) is lowered by heat loss at the furnace bottom, air suction from the tuyere, and the like.

When the furnace temperature is lowered, the viscosity of the slag increases, and it becomes difficult to discharge molten iron slag from the taphole provided at a height lower than the tuyere height. When the blast is performed in such a state, the liquid level of the molten iron slag (molten iron, molten slag, or a mixture thereof) in the lower portion of the furnace rises due to the molten iron and slag generated by the high-temperature gas generated in front of the tuyere. Since the molten iron slag supplied from the tuyere upper portion increases the temperature of the molten iron slag accumulated in the furnace bottom, there is no problem if the temperature is gradually returned to an appropriate furnace temperature level. However, if the furnace temperature is not restored and the liquid level of the molten iron slag reaches the tuyere height and closes the tuyere, the heat supply means for supplying heat into the furnace is cut off, resulting in a furnace cooling accident and a large economic loss.

In the case of a furnace cooling accident, even if air is blown from the tuyere portion as a heat supply means to the blast furnace, there is a problem that the tuyere portion is again closed by the generated melt. As a method for recovering from a furnace cooling accident, the following method has been conventionally adopted. That is, first, during the period of stopping the wind, the tuyere other than 1 to 2 tuyeres on the taphole is closed by a heat-resistant material or the like, and oxygen is blown into the tuyere through the taphole and the unclosed tuyere. Thus, after the semi-molten material between the tap hole and the tuyere is discharged from the tap hole, the space present in the furnace is filled with coke, and then blowing is started. After establishing a cycle of raising the temperature of the hearth by the high-temperature gas flowing between the taphole and the tuyere and smoothly discharging molten iron slag generated by the air blowing, the adjacent tuyeres are perforated to gradually increase the number of the perforated tuyeres and return to the normal operation. However, this procedure is long and takes 1 to 2 months. In addition, since oxygen is blown into the vessel manually, it is a high-safety work.

Since the furnace temperature is lowered, the start-up after the air cut is a state in which the risk of the furnace cooling accident described above is high. In order to start the furnace after stopping the blast without causing a trouble of furnace cooling, conventionally, the coke ratio in the furnace is increased until the blowing of the fine coke can be started, and the fine coke is not blown immediately after the blast until the blowing of the fine coke is started. In the case of using this method, there are problems as follows: after confirming the stable discharge of the molten iron slag, in order to reduce the charged coke ratio, the use ratio of the coke having a higher price than the fine coke is increased when the blast furnace is stopped, and thus the manufacturing cost per ton of molten iron is increased.

As another method, there have been proposed a blast starting method of a blast furnace and a burner for raising the temperature of the furnace bottom, in which a burner is provided at a tap hole provided in the furnace bottom of the blast furnace to burn fuel, thereby raising the temperature of the furnace bottom efficiently and enabling the furnace bottom to be started in a short time after a long-time air cut-off (patent document 1). In addition, in order to discharge molten iron in the blast furnace to the outside, a hole drill for drilling a hole in a tap hole has been proposed (patent documents 2 and 3).

Documents of the prior art

Patent document

Patent document 1, Japanese patent laid-open publication No. 2016-30833

Patent document 2 Japanese patent laid-open No. 2006-307258

Patent document 3 Japanese Kokai publication Hei-5-14140

Disclosure of Invention

Problems to be solved by the invention

In the tapping performed in the normal operation using the tapping drill as disclosed in patent documents 2 and 3, the tip of the tapping drill is melted by the high temperature of the molten iron flowing out of the furnace. Further, since a force for pushing the drill outward is applied by the action of the pressure in the furnace, the drill is not pulled out. However, the timing of opening the taphole of a lance (hereinafter, collectively referred to as a burner lance) provided with a burner for raising the temperature of the furnace bottom and/or a lance having a function of blowing combustion-supporting gas for raising the temperature of the furnace bottom is a period of air cut. During the periods of wind outage, the temperature in the furnace is low, and in the case of an outflow, it is mostly slag rather than molten iron, and therefore the heat to melt the open hole drill is insufficient. Therefore, when a tap hole for installing a burner lance is drilled using a hole drilling bit as disclosed in patent documents 2 and 3, coke enters a gap between the tap hole and the hole drilling bit after the tap hole is penetrated, and this causes a problem of resistance. Therefore, there are problems that the drill cannot be pulled back, and that the drill cannot be pulled back because molten material centered on slag in the furnace enters the tap hole together with coke.

In the case where the drill bit cannot be pulled back, the drill bit has been pushed further into the coke bed at a high temperature in the furnace and pulled back after melting. In this case, the melt may be buried in the tap hole, so that tapping must be performed again, and the tapping operation takes time. Further, when the drill rod is disconnected from the tapping bit when the tapping bit is attempted to be pulled out of the furnace, it is necessary to melt the tapping bit using oxygen. In this case, there is a problem that the work time is further prolonged because the work of oxygen cleaning and the step of re-drilling are increased.

The invention aims to provide a tapping drill and a tapping hole tapping method using the same, which can efficiently raise the temperature of the bottom of a blast furnace at a position lower than the height of a tuyere, can perform starting after long-time air cut-off and/or starting after furnace cold accident in a relatively short time, and can simplify the tapping operation of a tapping hole for installing a burner lance for raising the temperature of the bottom of the furnace.

Means for solving the problems

As a result of intensive studies to solve the above problems of the prior art and to achieve the above object, the inventors finally developed a new drill as described below. That is, the present invention is a hole drill for drilling a tap hole in a blast furnace bottom, the hole drill having a projecting piece on a rear surface of an excavation surface in a furnace, wherein an outermost end of the projecting piece is located inward of an outermost end of the hole drill.

In the drill according to the present invention configured as described above,

(1) the drill is considered to be a more preferable solution for opening a hole for installing a burner lance for raising the temperature of the hearth at the tap hole.

The present invention also provides a tapping hole opening method for opening a hole for installing a burner lance for raising the temperature of a blast furnace bottom in a tap hole in the blast furnace bottom, wherein the tapping hole is opened in the tap hole by using a tapping machine provided with the above tapping drill.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the open hole drill of the present invention, since the projecting piece is attached to the rear surface of the excavation surface in the furnace, even when the melt flowing backward at the time of boring flows outside the furnace of the open hole drill, the melt flowing outside the furnace of the open hole drill can be excavated by the projecting piece provided on the rear surface at the time of pulling back the open hole drill to the outside of the furnace, and therefore the open hole drill can be pulled out of the furnace.

Drawings

Fig. 1 is a schematic view for explaining a structure of an example of the drill of the present invention.

Detailed Description

The drill of the present invention will be explained below.

Fig. 1 is a schematic diagram for explaining a structure of an example of the hole drilling bit of the present invention. In the example shown in fig. 1, a projecting piece (chip)2 is attached to a digging surface 1a on the furnace inner side of the hole drill 1, and the projecting piece 2 is also attached to rear surfaces 1b and 1c of the digging surface 1 a. The protruding piece 2 is made of a material harder than the material of the object to be excavated, and cuts the object by coming into contact with the material of the object to be excavated. Cemented carbide is generally used as a material, and may be referred to by the names of a cemented carbide tab, a cutter, and the like. The attachment of the tab 2 may be performed by welding or the like. Reference numeral 3 denotes a drill rod for supporting the drill bit 1.

Here, the rear surface of the excavation surface of the hole drill 1 refers to the surfaces 1b and 1c closer to the drill rod 3 than the position of the attachment surface having the largest diameter, among the surfaces 1a, 1b and 1c to which the protruding piece 2 is attached. That is, the rear surface of the excavation surface is a surface which comes into contact with the melt when the drill is pulled back when the melt flows into the furnace outer side of the drill. The protruding piece attached to the back surface is preferably attached to a position where the protruding piece comes into contact with the melt and/or the solidified material thereof flowing into the outside of the furnace of the hole drill when the hole drill is pulled back. Alternatively, the projecting piece may be attached to a position where the projecting piece does not contact the excavation target when the hole drill is advanced.

In general, a hole drill used for drilling a tap hole has a protruding piece attached to a front surface of the hole drill, that is, a position that comes into contact with an object to be drilled when the hole drill is advanced, in order to cut the object to be drilled when the hole drill is advanced (see, for example, patent documents 2 and 3). However, the inventors have found that, when a burner lance for raising the temperature of the furnace bottom needs to be provided, there is a high possibility that the melt in the furnace flows backward while being perforated. Namely, it was found that: it is not sufficient to use only a function of enabling excavation when the drill is advanced, and it is effective to attach the protruding piece 2 to the back surfaces 1b and 1c of the drill.

In patent document 3, the hard tool corresponding to the protruding piece of the present invention is attached not only to the front surface of the drill, but also to the back surface of the drill at a position closer to the mounting surface having the largest diameter of the drill than to the outside of the outermost end of the drill. However, the hard cutter of patent document 3 is provided so as to cover the front portion of the air hole (hole) in order to suppress the closing of the air hole, and is not a member for excavating the melt flowing into the furnace outer side of the open hole drill when the drill is pulled back. I.e., different in function from the tab of the present invention. In patent document 3, no protruding piece is attached at a position closer to the radially inner side of the drill rod, that is, at a position inside the outermost end of the protruding piece than the outermost end of the hole drill. That is, in order to realize the function of excavating the melt flowing into the furnace outer side of the open hole drill when the drill is pulled back, which is necessary in the present invention, the object of the present invention cannot be achieved by the open hole drill of patent document 3.

In order to achieve the object of the present invention, it is effective to attach the protruding piece to the outermost end of the protruding piece at a position inside the outermost end of the hole drill. More specifically, it is preferable to have the tabs arranged as follows: the innermost point of the tab is located radially further inboard than the midpoint of the outer circumference of the drill rod and the outermost position of the hole bit.

As described above, for the failure due to equipment_·Operation failure_·In a method in which immediately before a blast furnace is started, for example, for maintenance of facilities, in which a long-term air-cut or a reduction in furnace temperature is performed, combustion-supporting gas and fluid fuel or inert gas are blown from a tap hole, or only combustion-supporting gas is blown to raise the temperature of a melt and a charge in the furnace, the piercing drill 1 of the present invention can contribute to shortening the time required for the piercing work in which a burner lance is installed to pierce the tap hole and the blowing is started.

That is, when the molten material is not sufficiently discharged to the outside of the furnace at the time of the intake of the stopped air, and/or when the molten material is generated during the stopped air and the molten material level (level) at the bottom of the furnace rises due to the intake of air from the tuyere portion or the like during the stopped air, the molten material flows back into the taphole at the time of tapping. In this case, even if the backflow is temporarily stopped and the tapping is performed again, the melt flows back into the tap hole, and therefore, the burner lance cannot be installed. In this case, the tapping hole can be temporarily closed by pulling back the tapping drill, the tapping hole can be again drilled to be shallower than the tapping depth, and water, air, or both of them can be blown in, whereby the backflow of the melt can be prevented while temporarily cooling the deep part of the hole, and the tapping hole can be drilled to the tapping depth.

When the melt is observed to flow back from the furnace, if tapping is still performed, the melt flowing back may flow out of the furnace to the tapping drill, and the tapping drill may not be pulled back out of the furnace. In the conventional method, the drill bit is further pressed into and inserted into a coke-filled layer in the furnace, and the drill rod is pulled back after the drill bit is melted. In this case, it is necessary to perform the hole opening again, and the hole opening operation takes time. Further, when the drill rod is disconnected from the tapping drill when the tapping drill is pulled out of the furnace, it is necessary to melt the tapping drill with oxygen. In this case, in addition to the step of performing the oxygen cleaning operation and the step of re-boring, the taphole closing material is melted by the oxygen cleaning operation, and the depth of boring is unclear, and therefore, it may be difficult to perform the above-described operation.

According to the hole-opening drill 1 of the present invention shown in fig. 1, since the protruding pieces 2 are attached to both the excavation surface 1a on the furnace inner side and the rear surfaces 1b and 1c on the furnace outer side, the tap hole closing material and/or the coke is hit and rotated by the protruding pieces 2_·The slag can be cut to open and/or dig holes in both the furnace interior direction and the furnace exterior direction. Therefore, even in a situation where the melt flows backward from the furnace, the hole for installing the burner lance can be opened while cooling the backward-flowing melt, and the drill can be pulled back. It has not been known to apply a load to the drill bit and/or drill rod to the extent that the back-mounted tab opening drill bit is pulled back. The inventors investigated whether or not the solidified melt can be excavated under the condition that the melt flows backward under various conditions, and as a result, they found that the load on the drill and/or the drill rod required for excavation at the time of drawing back is not excessively large as compared with the case of boring in the furnace direction, and that the drill and/or the drill rod can be drawn back at a normal drawing back speedThe excavation is performed without any problem. When the load during excavation is large, the load applied to the drill rod is monitored by a load sensor or the like, and when the load is large, the pull-back speed is reduced, whereby the drill bit and/or the drill rod can be pulled back while preventing damage.

Examples

Next, examples of the present invention will be described, and the conditions in the examples are conditions employed for confirming the feasibility and effects of the present invention, and the present invention is not limited to these conditions. In the present invention, various conditions can be adopted as long as the object of the present invention can be achieved without departing from the gist of the present invention.

(example 1)

The taphole is usually tapped for setting the burner lances at start-up after a wind stop. The tapping utilizes two types of tapping bits, i.e., a tapping bit having a maximum diameter of 70mm and a tapping bit having a maximum diameter of 110mm, in the shape shown in fig. 1. After the penetration by the drill having a diameter of 70mm was confirmed, the drill rod could not be pulled back from the furnace, and therefore, the drill was hit and rotated in the opposite direction, and as a result, the drill could be pulled back while maintaining a sound state. Further, it was confirmed that solidification of slag was observed in the tap hole in the vicinity where the drill bit could not be pulled out. It was heretofore the case that reverse striking or melting by oxygen was selected to be continued until the opening bit was removed from the drill rod, but the opening bit according to the present invention confirmed that the opening bit could be pulled back without damage. The same situation can be applied to boring and bit pull-back even when a 110mm diameter boring bit is used.

Industrial applicability of the invention

According to the drill of the present invention, even when the melt flows back into the tap hole, the drill can be pulled back without damage. Therefore, the drill of the present invention can be used in various vertical furnaces other than blast furnaces, which are considered to be possible to be drilled.

Description of the reference numerals

1-hole drilling bit

1a digging surface

1b, 1c back side

2 projecting piece

3 drill rod