JPH09165826A - Splice plate to enhance joining efficiency at frictional joining time of high strength bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance frictional joining efficiency, and improve safety by giving a concentric circle-shaped recess-projection pattern to the peripheral edge of a bolt hole of a splice plate to sandwich a joining part of a steel structure such as a bridge from both surfaces, by knurling pieces. SOLUTION: A concentric circle-shaped recess-projection pattern with a bolt hole as the center is given to the peripheral edge of a bolt hole of a splice plate for frictional joining by a high strength bolt by rolling by knurling pieces, and hardness of a projecting part of the pattern is hardened by work hardening and quenching. When this recess-projection pattern is given, plural knurling pieces are installed in a symmetrical or regular polygon shape in a drill and a rod fixed to a rotary work machine such as a drilling machine, and rolling is performed. A depth of the recess-projection pattern is made deep in roughness or more of a surface given by a shot blast or the like, and a frictional coefficient is made large when it is fastened by a bolt. Therefore, reliability of a frictional joining part can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splice plate for high-strength bolt friction joining, and can be used for friction joining portions of steel structures in buildings, bridges and the like. By using the steel material of the present invention, it is possible to stably obtain a high friction coefficient of the friction-bonded surface and enhance the safety of the steel structure.

[0002]

2. Description of the Related Art In the case of high-strength bolt friction joining, according to the design and construction guidelines of the Architectural Institute of Japan, the friction surface that is important for joining strength is a good red rust surface with black scale removed and a slip coefficient of 0.
It is said that it is necessary to perform a treatment exceeding 45 and to check the slip coefficient by a slip resistance test. Normal,
In a good red rust state, the slip coefficient is known to exceed 0.45, and the slip resistance test is often omitted.

A slip coefficient of about 0.6 may be obtained in the red rust state, but the rust generation state varies depending on environmental factors, steel material composition, etc., so there is a large variation, and the slip coefficient is designed to be 0.45. It seems that It is clear that the slip coefficient of the friction-bonded surface is preferably as high as possible in terms of bonding strength, and in JP-A-51-52628, the joint surface is made uneven before construction, or in JP-A-1-206104. High corrosion resistance is generated by spraying corrosion resistant metal.

However, although the slip coefficient tends to increase as the surface roughness of the steel material increases, there is a problem in that even if the surface roughness is increased, it does not exceed a certain value. In addition, the method of imparting surface roughness (unevenness) has not come into widespread use in terms of cost and convenience.

[0005]

DISCLOSURE OF THE INVENTION The present invention has a rolling pattern of knurled pieces on the periphery of a bolt hole on the friction-bonding surface of the splice plate, and the protrusions thereof are harder than the base steel material to be joined, so that stable The present invention provides a splice plate for high-strength bolt friction joining that exhibits a high slip coefficient.

[0006]

The gist of the present invention is as follows. (1) At the time of high-strength bolt friction welding, characterized in that the knurled piece is rolled and rolled concentrically around the bolt hole on the friction welding surface of the splice plate to provide a concavo-convex pattern. Splice plate that enhances the joining efficiency of.

(2) When roughness is imparted by a knurled piece, a knurled piece is provided at a position corresponding to a region to be provided with a concavo-convex pattern on a cone or a rod which can be fixed to a drilling machine, a drilling machine with an NC device or a portable drilling machine. A splicing plate that enhances the joining efficiency during high-strength bolt friction joining according to (1), characterized in that a concavo-convex pattern is imparted by a machining tool that is assembled in combination as needed.

(3) The high-strength bolt according to (1), characterized in that the knurling piece group is provided with a concavo-convex pattern by a working tool in which two sets or a plurality of sets of regular polygonal shapes are symmetrically attached around a cone or a rod. A splice plate that enhances the welding efficiency during friction welding. (4) The splice plate that enhances the welding efficiency during high-strength bolt friction welding according to (1), characterized in that the hardness of the convex portions of the provided concavo-convex pattern is higher than the surface hardness of the mother steel plates to be welded.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In order to increase the slip coefficient of a steel material (splice plate), a method of increasing the surface roughness of a friction-bonded surface by shot or grid blast is generally used. However, the surface roughness due to these treatments depends on the type of steel and shot grains, but the ten-point average roughness Rz
The maximum value is about 150 μm, and there is a limit to the increase in the slip coefficient.

Therefore, the inventors first examined various methods for easily obtaining unevenness having a roughness not less than that which can be imparted by this shot blasting treatment. As a result, productivity was low with chemical methods such as machining such as cutting, electrical discharge machining, or etching, and it was insufficient in terms of convenience considered to be the most important for practical use. On the other hand, it was found that the application of the concavo-convex roll by rolling and rolling of the concavo-convex roll was relatively easy and the productivity was good. After that, improvements were made and the present invention using a knurled piece was achieved.

Further, according to the research conducted by the present inventors, in order to increase the slip coefficient with the same surface roughness, the hardness of at least the convex portion of the splice plate is made higher than that of the mother steel plates to be joined, The inventors of the present invention have obtained the knowledge that it is effective to cut into the mother steel plates to be joined, and have reached the present invention.

The present invention will be described below. From the viewpoint of the slip coefficient, the higher the roughness of the friction-bonded surface of the splice plate and the higher the surface hardness, the better. The sharper the tip of the convex portion is, the more preferable. First, the roughness of the friction-bonded surface was determined by rolling the knurled piece from the viewpoint of cost and simplicity. At that time, it is possible to roll on the steel plate by the reciprocating motion of the knurling piece, but in consideration of rolling with higher efficiency, using a rotary processing machine typified by a drilling machine, a cone that can be fixed to them is used. Alternatively, the processing is performed by using a processing tool in which a commercially available knurling piece is attached to the rod.

At this time, it is possible to combine a plurality of knurled pieces depending on the area to be provided with the uneven pattern. Although it is possible to use a wide knurled piece, in the present invention using a rotary processing machine such as the above-described drilling machine, the sharpness of the tip of the convex portion of the uneven pattern on the outside cannot be ensured due to the difference between the inner ring and the outer ring. Therefore, the width of one knurl piece is preferably 8 mm or less. Further, by combining a plurality of them, it is possible to change the height and pitch of the unevenness for each radial position, and it is also possible to provide the optimum unevenness according to the axial force distribution at the time of bolt fastening.

The concavo-convex pattern due to the rolling of the knurled piece is determined by the selection of the knurled piece. Can be easily applied. According to a study by the inventors, a twill pattern is most preferable if the area is the same.

Further, two sets of knurl pieces may be symmetrically attached to the above-mentioned cone or rod or a plurality of regret pieces may be attached in a regular polygonal shape so that rolling can be performed more efficiently, and depending on the arrangement of the knurl pieces, a twill pattern. Can also be given. These friction-bonding surfaces may be unevenly formed on the entire friction-bonding surface, but if the axial force distribution at the time of bolt fastening is taken into consideration, unevenness is concentrically formed around the bolt hole in the periphery of the bolt hole. That is the most effective in practice, and it is very efficient to give a concavo-convex pattern with a processing tool attached to a rotary processing machine.

According to the experiments conducted by the inventors, the area provided with the uneven pattern is most preferably about 1.5 to 3 times the bolt hole diameter, although it depends on the uneven pattern, but it is not always necessary to cover the entire area within the area. Absent.

Although the height of the unevenness is not specified,
Roughness (height difference) or more that can be easily imparted by shot blasting, that is, 0.15 mm or more is preferable, and there is a limitation of the knurling piece for the upper limit, but even if it exceeds 2 mm, the slip coefficient does not significantly increase, Effectively it is 2 mm or less.

In order to further improve the slip coefficient after providing the uneven surface on the friction-bonded surface as described above, at least the hardness of the convex portion needs to be higher than the surface hardness of the mother steel plates to be bonded. This is necessary in order to maximize the anchoring effect that the convex portion bites into the mother steel plate to be welded, and it is necessary to be harder than the surface hardness of the mother steel plate to be welded, and a Vickers hardness of 50 or more. Is preferred.

When the hardness of the convex portion is lower than the surface hardness of the mother steel sheet to be joined, the biting is insufficient, and the unevenness (roughness) provided is crushed, so that the effect of providing unevenness cannot be sufficiently exerted. The upper limit of hardness is not specified, but it is obvious that there is a limit depending on the composition of the steel. Note that this hardness is required at least in the convex portion and does not need to cover the entire cross section of the splice plate, and it is rather preferable that only the vicinity of the convex portion is hard in consideration of drilling of bolts.

Rolling tends to become slightly harder by itself because it involves plastic deformation. However, performing various hardening treatments such as quenching after rolling will rather exert the effect of the present invention. Yes preferred. In addition, if high-strength steel that already has a sufficient surface hardness is used, it is possible to satisfy the requirements of the present invention only by providing unevenness by rolling without performing surface hardening treatment.

[0021]

EXAMPLES Table 1 shows combinations of mother steel plates to be joined and splice plates used to illustrate the usefulness of the present invention,
The slip coefficient as a result is shown in Example 1
10 to 10 are examples of the present invention, and Examples 11 to 13 are comparative examples.
In addition to the roughness and surface hardness of each friction joint surface,
For the splice plate, the area and method for imparting surface roughness, the surface hardening method, etc. are also described.

[0022]

[Table 1]

The surface hardness in the table means 0.1 mm from the outermost surface.
It is the average value of Vickers hardness measured from the bottom to 0.5 mm with a 0.1 mm pitch and a load of 200 g. The slip coefficient was measured using the combinations shown in Table 1 and the test pieces shown in FIG. In the measurement, the mother steel plate 1 to be joined, the jig plate 4 were the same steel plate (SM490 steel), the bolt 3 was F10T, and the concavo-convex pattern according to the present invention was applied to the splice plate 2.

Since each of Examples 1 to 10 has the surface roughness (Rz) and the surface hardness of the friction-bonded surface as described in the claims of the present invention, it exhibits a high slip coefficient of 0.75 or more. doing. On the other hand, in Comparative Examples 11 to 13, as shown by the hatching in Table 1, the splicing plate friction joint surface, which is a constituent element of the present invention, is not provided with an uneven pattern, or the hardness of the convex portion is to be joined. The slip coefficient is generally low because it is lower than that of the mother steel sheet.

[0025]

According to the present invention, a stable and high slip coefficient can be easily obtained. As a result, it can be provided as a structural member that enhances the reliability of the high-strength bolt friction joint in the fields of construction and bridges, and its industrial value is great.

[Brief description of the drawings]

FIG. 1 (a1), (a2) and (b) are schematic diagrams showing a concavo-convex pattern, and (b) is a most preferable twill pattern.

FIG. 2A is a side view and FIG. 2B is a plan view of a test body for measuring a slip coefficient.

[Explanation of symbols]

 1: Bonded mother steel plate 2: Splice plate (steel of the present invention) 3: Bolt 4: Jig plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Kobayashi 1752 Kutsuma, Kisarazu-shi Kobayashi Seimitsu Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A high-strength bolt friction characterized in that a knurled piece is rolled and rolled concentrically around the bolt hole on the friction joint surface of the splice plate to form a concavo-convex pattern. A splice plate that enhances the joining efficiency during joining. 2. When imparting roughness with a knurling piece, a knurling piece is provided at a position corresponding to a region to be provided with a concavo-convex pattern on a cone or rod that can be fixed to a drilling machine, a drilling machine with an NC device or a portable drilling machine. The splice plate for increasing the joining efficiency at the time of high-strength bolt friction joining according to claim 1, characterized in that a concavo-convex pattern is provided by a plurality of machining tools attached in combination as necessary. 3. The high-strength bolt friction according to claim 1, wherein the knurling piece group is provided with a concavo-convex pattern by a processing tool in which two sets or plural sets of regular polygonal shapes are symmetrically attached around a cone or a rod. A splice plate that enhances the joining efficiency during joining. 4. The splice for increasing the joining efficiency during high-strength bolt friction joining according to claim 1, wherein the hardness of the convex portions of the provided uneven pattern is higher than the surface hardness of the mother steel sheet to be joined. plate.