JP2007160387A - Joining method of bar steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bar steel joining method which can improve workability as well as suppress increase in cost by ensuring and facilitating the packing of welding wire into a gap situated between the ends. <P>SOLUTION: In the bar steel joining method, the ends of bar steels 1, 2 are placed opposite to each other, with a welding wire 6 made to situate in a groove constituted by a gap W provided between the ends, and with the welding wire 6 fused to join the ends of the bar steel. In a state where an intermediate member 4 having a size enough to form the gap W for the groove inside is arranged, the ends are pressed against the intermediate member 4. Then, the intermediate member 4 is irradiated with an arc, thereby fusing the welding wire 6 and welding the ends to each other, which is the characteristic of the joining method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of joining steel bars used for reinforcing bars and the like, and more particularly, to a method of butt welding end portions of steel bars.

  As is well known, when a reinforced concrete structure is constructed with an RC laminated structure or the like, a steel bar or the like is used as an aggregate embedded in the concrete. The butt construction method is used before the concrete is placed.

  Known methods of joining the ends of the reinforcing bars include an electric pressure welding method such as an upset method and arc welding in which an arc is generated from an electrode to melt the weld metal (for example, Patent Document 1).

  Among the above methods, arc welding is a welding wire by generating an arc toward a groove formed between opposite ends of a reinforcing bar, such as arc welding using a carbon dioxide semi-automatic welding machine. This is a method of filling the welding wire melted between the end portions by melting the ends and joining the end portions to each other (for example, Patent Document 1).

  By the way, when irradiating an arc to the groove portion formed between the ends of the reinforcing bar, in order to prevent the gap from forming the groove portion from being ejected to the side opposite to the arc irradiation side. The outer peripheral surface opposite to the arc irradiation side, that is, the outer peripheral surface on the side where the arc may be ejected is covered with a backing member or the like. As a result, the metal melted together with the arc is dammed by the backing member on the side opposite to the irradiation side, and the ends are melted by arc heat and filled with the melted metal so that the molten metal accumulates in the groove portion. It can be joined (for example, Patent Document 1).

JP 09-253893 (paragraphs “0002” and “0003” columns)

  Explaining the construction method disclosed in the above publication, as shown in FIG. 4, the ends of the reinforcing bars A and B to be joined are made to face each other using the clamp members A1 and B1, and the gap W between the ends is provided. The welding wire C to be gripped and operated by the operator is positioned with respect to the inside, and an arc is irradiated. Prior to this, a backing member D having a size capable of covering the gap W between the ends is attached to the outer peripheral surface of the reinforcing bars A and B on the insertion side of the welding wire C, that is, the side opposite to the arc irradiation side. Thus, the arc and molten metal are prevented from passing through the gap W and being ejected to the outside.

However, this method has the following problems.
By providing the backing member D, it is possible to prevent the metal melted outward from the gap W from leaking out. On the other hand, when the backing member D is viewed from the arc irradiation side, the deepest position of the gap W, that is, the so-called back side. It will be provided. For this reason, when the welding wire is inserted into the gap W, it is difficult to confirm the tip position, and it is difficult to confirm the molten state of the welding wire.
If the molten state cannot be confirmed in this manner, it may not be possible to determine whether or not the welding wire is filled between the ends of the reinforcing bar on the back side of the gap W, and the necessary joint strength may not be ensured.

  Therefore, it is conceivable to brighten the position of the welding wire on the back side of the gap using a backing member having an opening as disclosed in Patent Document 1, but in this case, welding melted from the opening The wire rod will leak out, and the consumption of the welding wire rod required to fill the gap W between the end portions may increase.

  When the backing member is provided, it is difficult to confirm because the distal end position of the welding wire is located on the back side in the groove portion and becomes relatively night vision, or when an opening is provided. Considering that leakage from the opening occurs, it is necessary to increase the pressure of the gas used for welding, thereby increasing not only the consumption of the above-mentioned welding wire but also the consumption of gas and power. As a result, the cost required for the joining work may increase.

  The object of the present invention is to improve the workability and increase the cost by reliably and easily filling the welding wire into the gap located between the ends in view of the problems in the conventional steel bar joining method. An object of the present invention is to provide a steel bar joining method capable of suppressing the above.

The present invention has the following configuration.
(1) The ends of the steel bars are made to face each other, the welding wire is positioned in a groove portion formed by a gap provided between the ends, and the ends are melted by melting the welding wire. In the joining method of the steel bars to be joined, the end portions are pressed against the mediating member in a state in which the mediating member having a size sufficient to form the gap is arranged in the groove portion, and directed toward the mediating member. A steel bar joining method characterized by melting the welding wire by irradiating an arc and joining the ends.
(2) The steel bar joining method according to (1), wherein the mediating member is positioned in a state of substantially traversing the central portion of the steel bar.
(3) The steel bar joining method according to (1) or (2), wherein the mediating member has a length corresponding to the diameter of the steel bar.
(4) The steel bar joining method according to any one of (1) to (3), wherein the intermediate member is configured not to roll within the gap.
(5) The steel bar joining method according to (4), wherein the intermediate member is a polygonal member or a circular member.
(6) The steel bar joining method according to any one of (1) to (5), wherein the intermediate member is made of a material that can be embedded in a molten welding wire.
(7) The steel bar is inserted into the gap by defining a facing position by a clamp member which can be arranged to face each other in a state where the gap is formed at the end of the steel bar (1) ) To (5) a steel bar joining method according to any one of the above.

  According to the present invention, unlike the conventional construction method, a backing member is not provided on the outer peripheral surface of the steel bar, but an intermediate member having a dimension sufficient to form this gap is disposed in the gap. This makes it easier to confirm by the fact that the position of the tip of the welding wire is less likely to become a night vision state like the back side of the gap when the arc irradiation side is used as a reference, unlike when a backing member is provided on the outer peripheral surface. Become.

  Moreover, since the arc is irradiated toward the mediating member, it is difficult for the arc or molten metal to be ejected toward the outside of the groove portion without providing a backing member, and the arc is directed from the position of the mediating member toward the arc irradiation side. As a result, molten metal accumulates. As a result, the size of the arc only needs to reach the position of the mediating member rather than to the back side of the gap, so it is possible to reduce the amount of power consumption and gas consumption and suppress the increase in work cost. .

  In particular, in the inventions of claims 2 and 3, since the mediating member crosses the diameter center portion of the steel bar and the length thereof corresponds to the diameter, most of the arc and molten metal irradiated in the groove portion Can be dammed up.

  Further, in the inventions according to claims 4 and 5, the mediating member has a shape that does not roll in the groove portion, and can be easily placed by using a square shape or an elliptical shape, It is possible to secure stability when the ends of the steel bars come into contact with each other, and to prevent the steel bars from being pushed and moved by the arc or the molten metal.

  Further, in the invention described in claim 6, since the mediating member is a material that can be embedded when the welding wire is melted, depending on the selection, it can be used as an aggregate having higher rigidity than the welding wire.

  In the seventh aspect of the present invention, the gap constituting the groove is defined by the positioning of the end portions by the clamp member, so that the action when the mediating member is used is prevented by preventing the mediating member from falling off. It becomes possible.

  The best mode for carrying out the present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is a schematic view for explaining a method for joining sheet steel bars according to an embodiment of the present invention.
In FIG. 1, steel bars 1 and 2 for reinforcing bars to be joined are attached to a clamp device 3 that grips and positions the vicinity of these end portions.

  The clamp device 3 includes channel-shaped gripping portions 3B on both sides in the longitudinal direction of the base plate 3A. The gripping portion 3B uses bolts 3C at positions facing the base plate 3A with the steel bars 1 and 2 interposed therebetween. A frame 3D that is movable in the axial direction of the lever 3C is provided.

  The steel bars 1 and 2 are fixed in a state in which the outer peripheral surfaces in the vicinity of the end portions are sandwiched between the base plate 3A and the frame body 3B and the axes are aligned.

  On the other hand, the steel bars 1 and 2 are provided with a gap W that forms a groove between opposing ends, and the gap W has a dimension sufficient to form the gap W. The member 4 is arranged.

  The intermediary member 4 is a member that is disposed between the ends of the steel bars 1 and 2 so as to cross the center of the diameter of the steel bars 1 and 2 and has a length corresponding to the diameter of the steel bars 1 and 2. Has been.

As the form of the mediating member 4, a form that does not roll in the gap W is selected, and in this embodiment, as shown in FIG. 2, a rectangle or a circle such as a screw 5 as shown in FIG. 3. A polygonal member such as a nut 5A is attached to both ends of the member so that the state where the member does not roll can be maintained. As another form of the mediating member 4, a polygonal shape or an elliptical shape can be selected.
2 and 3, (A) shows a part of the appearance of the steel bar, and (B) shows a part of the front of the steel bar.

  Since the mediating member 4 is disposed in a state of traversing the diameter center of the steel bars 1 and 2 inside the gap W, a material that can be embedded in the molten metal generated when the welding wire is melted is used. In this embodiment, the surface layer is melted by the heat of the arc, and a material having an affinity for the end of the steel bar that is partially melted by the arc heat and an affinity for the molten metal is selected. Thereby, after welding, it functions as an aggregate in the gap W, and the strength at the joint can be secured. As the material, a material that has higher mechanical strength than the molten metal after cooling hardening and does not melt during welding is preferable, and a material having a melting temperature slightly higher than the molten metal and having the same melting temperature as the steel bar is selected. The

In the present embodiment, the following procedure is used by using the above configuration.
(1) The vicinity of the ends of the steel bars 1 and 2 is gripped by the clamp device 3, and a gap W corresponding to the groove portion is set.
(2) The intermediate member 4 is arranged in a state of crossing the diameter centers of the steel bars 1 and 2 inside the gap W, and the ends of the steel bars 1 and 2 are brought into contact with the intermediate member 4 to maintain the state.
(3) Insert the welding wire 6 attached to the welding electrode into the gap W.
The tip of the welding wire 6 at this time is the center position of the steel bars 1 and 2 where the mediating member 4 is arranged, not inserted in the gap W to the back side when viewed from the insertion side of the welding wire 6 Mu For this reason, unlike the case where it inserts in the back | inner side, it will be in the state which is easy to observe the front-end | tip of the wire 6 for welding.
In particular, when the welding wire 6 is inserted deep inside the gap W, it is necessary to check the welding position in a relatively night vision position, so the position of the welding wire 6 is unstable. However, in this embodiment, such a state can be avoided, so that it is possible to easily confirm the welding position and position the tip of the welding wire 6.
(4) Start welding and irradiate the arc toward the mediating member 4. This state is as shown in FIG.
At this time, since the arc and the molten metal are blocked by the mediating member 4, the molten metal is removed from the inner side of the gap W, that is, from the opposite side to the side where the welding wire 6 is inserted. There is no eruption towards the outside. As a result, the molten metal is accumulated from the position of the mediating member 4 toward the insertion side of the welding wire 6 (in FIG. 1, the state where the molten metal is accumulated is indicated by a light black portion indicated by symbol S). ).
In this way, by being able to work in a state where the welding position can be easily confirmed, the intermediate member 4 can be used as a damming position, and a relatively small range up to the insertion side of the welding wire 6 on the front side can be used as a molten metal. Can be sufficiently filled.
Moreover, the welding work range can be approximately half of the area of the groove portion located between the ends of the steel bars 1 and 2 with the intermediate member 4 as a reference. As a result, since the filling amount does not become unstable, the size of the arc can be adjusted accordingly, and the power consumption and the gas consumption amount can reach the back side in the gap W. It can reduce compared with the case.

  On the other hand, when the welding operation for the half region in the gap W is completed with the mediation member 4 as a boundary, the welding operation is performed from the opposite side across the mediation member 4 for the remaining half region.

  In this embodiment, welding work is performed from the opposite direction of the half region of the groove portion with the mediating member 4 as a boundary, and at first glance, it seems to be troublesome, but confirmation of the welding position in the night vision state As a result, the time required for confirming the welding position can be saved, thereby reducing the work time.

  On the other hand, at the time of welding, part of the end portions of the steel bars 1 and 2 are melted by arc heat, and part of the outer layer of the mediating member 4 is also melted. They will be joined together.

  When the joining between the end portions is completed, the intermediate member 4 having higher strength than the molten metal is embedded in the molten metal, so that the strength at the joint can be increased as compared with the case where only the molten metal is used.

It is a schematic diagram for demonstrating the working state of the joining method of the steel bar by the Example of this invention. It is a figure which shows an example of the mediation member used for the joining method shown in FIG. It is a figure which shows the other example of the mediation member used for the joining method shown in FIG. It is a schematic diagram for demonstrating the prior art example regarding the joining method of a steel bar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Steel bar 3 Clamp apparatus 4 Mediating member 5 Screw used as mediating member 5A Nut attached to screw used as mediating member 6 Welding wire W Gap which comprises groove part

Claims (7)

Steel bars for joining the ends by facing the ends of the bars and positioning the welding wire in a groove formed by a gap provided between the ends and melting the welding wire In the joining method of
The end portions are pressed against the intermediary member in a state where the intermediary member having a size sufficient to form the gap is disposed with respect to the inside of the groove portion, and an arc is irradiated toward the intermediary member A steel bar joining method characterized by melting a welding wire and joining the ends together.   2. The method of joining steel bars according to claim 1, wherein the intermediate member is positioned in a state of crossing substantially the center of the diameter of the steel bar.   The steel bar joining method according to claim 1 or 2, wherein the mediating member has a length corresponding to a diameter of the steel bar.   The steel bar joining method according to any one of claims 1 to 3, wherein the intermediate member is configured not to roll within the gap.   5. The steel bar joining method according to claim 4, wherein the intermediate member is a square member or an elliptical member.   6. The steel bar joining method according to claim 1, wherein the intermediate member is made of a material that can be embedded in a molten welding wire. The steel bars are inserted into the gap by defining a facing position by a clamp member which can be arranged to face each other in a state where the gap is formed at the end of the steel bars. The steel bar joining method according to any one of the above.

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