Method for suppressing twisting of reinforcing bars with ribs

Abstract

To provide a method for suppressing twisting of reinforcing bars with ribs that eliminates problems such as poor transportability due to the absence of twisting along the entire length, and the tendency for surface roughness to occur. [Solution] As a post-process of forming nodes S and ribs R with the node and rib forming rolling roll 1, a pair of rolls 2 installed downstream of the node and rib forming rolling roll 1 of the rolling mill are used, and rolls 2 having a width W1 that is larger than the width W of the rib R of the node reinforcing bar B are used to press down on the rib R of the node reinforcing bar B from both sides with these rolls 2, thereby correcting the twist that occurs in the node reinforcing bar B by applying plastic deformation to the center of the node reinforcing bar B.

Description

Technical Field

[0001] The present invention relates to a method for suppressing twist of deformed steel bars, which suppresses twist generated in deformed steel bars and improves the shape of deformed steel bars when manufacturing deformed steel bars (steel bars with ribs and nodes such as bamboo nodes or diagonal nodes formed in the circumferential direction on the surface of the steel bars and ribs formed in the longitudinal direction to enhance the adhesion strength with concrete. In this specification, the nodes such as bamboo nodes or diagonal nodes formed in the circumferential direction on the surface may simply be referred to as "nodes").

Background Art

[0002] By the way, when manufacturing deformed steel bars by rolling, the deformed steel bars with ribs tend to induce twist caused by forming nodes and ribs, resulting in a problem that the shape accuracy of the deformed steel bars decreases. In addition, the deformed steel bars tend to have a step at the boundary between the nodes and the ribs, and have poor rolling properties, so there are also problems such as poor transferability and the surface of the ribs being prone to roughness.

[0003] By the way, the applicant of the present application previously proposed a method for suppressing twist of screw deformed steel bars that can produce screw deformed steel bars without twist over the entire length by applying uniform deformation from the side even in the case of products with non-uniform properties over the entire length (see Patent Document 1).

[0004] This method for suppressing twist of screw deformed steel bars corrects the twist generated in the screw deformed steel bars by plastically deforming the screw deformed steel bars with screw-shaped nodes formed by rolling rolls for screw shape forming using a pair of rolls installed on the downstream side of the rolling mill for screw shape forming. A convex roll with an arc-shaped cross-sectional shape is used for the pair of rolls, and the portion where the screw-shaped nodes of the screw deformed steel bars are not formed is pressed from both sides, and plastic processing is applied to the central portion of the screw deformed steel bars to correct the twist generated in the screw deformed steel bars.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Patent No. 7340677 [Overview of the project] [Problems that the invention aims to solve]

[0006] In view of the problems with conventional reinforcing bars having ribs, the present invention aims to provide a method for suppressing twisting of reinforcing bars having ribs, which improves upon the method for suppressing twisting of reinforcing bars having ribs disclosed in Patent Document 1, thereby solving problems such as the lack of twisting throughout the entire length, poor transportability, and the tendency for surface roughness to occur. [Means for solving the problem]

[0007] To achieve the above objective, the method for suppressing twisting of a ribbed reinforcing bar according to the present invention is: A method for suppressing twisting of reinforcing bars with ribs, wherein the reinforcing bars, which have formed nodes and ribs using rolling rolls for node and rib forming in a rolling mill, are plastically deformed using a pair of rolls installed downstream of the rolling mill, thereby correcting the twisting that occurs in the reinforcing bars. As a post-process to the step of forming the nodes and ribs with the aforementioned node and rib forming rolling rolls, the process includes using a pair of rolls installed downstream of the rolling mill, each roll having a width larger than the width dimension of the node reinforcing rib, and pressing down on the node reinforcing rib from both sides with these rolls, thereby correcting the twisting that occurs in the node reinforcing by applying plastic deformation to the center of the node reinforcing. It is characterized by the following:

[0008] In this case, the pair of rolls may be provided with an arc-shaped groove in the center in the width direction having a width dimension greater than the width dimension of the rib of the reinforcing bar.

[0009] Furthermore, the process may include installing a roll equipped with a pattern-forming recess between the rolling rolls for forming the nodes and ribs of the rolling mill and a pair of other rolls, and using the roll to press down on the ribs of the node reinforcement from both sides, thereby forming a convex pattern on the surface of the ribs of the node reinforcement. [Effects of the Invention]

[0010] According to the twist suppression method for ribbed reinforcing bars of the present invention, as a post-process of the process of forming nodes and ribs with rolling rolls for forming nodes and ribs of a rolling mill, a pair of rolls installed downstream of the rolling mill are used, each having a width larger than the width dimension of the ribs of the reinforcing bar. These rolls press down on the ribs of the reinforcing bar from both sides, applying plastic deformation to the center of the reinforcing bar. This provides a simple mechanism that eliminates twisting along the entire length, solves problems such as poor transportability and surface roughness, and provides a twist suppression method for ribbed reinforcing bars. [Brief explanation of the drawing]

[0011] [Figure 1] This is an explanatory diagram showing one embodiment of a rolling process that implements the method for suppressing twisting of ribbed reinforcing bars according to the present invention. [Figure 2] This is an explanatory diagram showing the main parts of the rolling process. [Figure 3] This is an explanatory diagram of reinforcing bars. [Figure 4] In the diagram illustrating the reinforcing bars, (a) is a bamboo-joint reinforcing bar, and (b) is a diagonal-joint reinforcing bar. [Figure 5] This is an explanatory diagram showing the deformation of the rolling process in which the method for suppressing twisting of ribbed reinforcing bars of the present invention is implemented. [Figure 6] The images show a ribbed rebar, with (a1) being a plan view of a conventional rebar, (a2) being a front view of the same, (a3) ​​being a cross-sectional view of the same, (b1) being a plan view of a rebar that implements the twist suppression method for ribbed rebars of the present invention, (b2) being a front view of the same, and (b3) being a cross-sectional view of the same. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the method for suppressing twisting of ribbed reinforcing bars according to the present invention will be described with reference to the drawings.

[0013] Figures 1 to 4 show one embodiment of the method for suppressing twisting of ribbed reinforcing bars according to the present invention. The method for suppressing the twist of the deformed steel bar with ribs is to plastically deform the deformed steel bar B with sections S and ribs R formed by the sections and rib-forming rolling rolls 1 of the rolling mill using a pair of rolls 2 installed on the downstream side of the rolling mill, thereby correcting the twist generated in the deformed steel bar B. As a subsequent process to the process of forming the sections S and ribs R by the sections and rib-forming rolling rolls 1, a roll 2 having a width dimension W1 larger than the width dimension W of the rib R of the deformed steel bar B is used for the pair of rolls 2 installed on the downstream side of the rolling mill, and the rib R of the deformed steel bar B is pressed from both sides by this roll 2, and plastic working is applied to the central part of the deformed steel bar B, thereby correcting the twist generated in the deformed steel bar B.

[0014] Here, the sections and rib-forming rolling rolls 1 are rolling rolls used to form the sections S and ribs R on the reinforcing bar material B0. Specifically, depending on the shapes of the sections S and ribs R of the deformed steel bar B to be manufactured, various rolling rolls can be used according to the bamboo-like sections shown in FIGS. 3 and 4(a) and the sections S such as the diagonal sections shown in FIG. 4(b).

[0015] For the pair of rolls 2, it is also possible to use flat rolls with the entire outer peripheral surface being a cylindrical smooth surface so as to uniformly press the entire surface of the rib R of the deformed steel bar B. However, as shown in this embodiment, a roll 2 provided with an arc-shaped concave groove 21 having a width dimension W2 larger than the width dimension W of the rib R of the deformed steel bar B at the central part in the width direction of the roll 2 is used. Thereby, by pressing both edge portions of the rib R from the radial direction, plastic working can be applied toward the central part of the deformed steel bar B, and the twist generated in the deformed steel bar can be surely corrected.

[0016] Table 1 shows an example of the specifications of the deformed steel bar B and the pair of rolls 2 (D: diameter of the maximum diameter part of the deformed steel bar B, W: width dimension of the rib R, R1: radius of the roll 2, D1: axial distance between the pair of rolls 2, W1: width dimension of the roll 2, W2: width dimension of the concave groove 21, H: depth dimension of the concave groove 21, r: radius of curvature of the concave groove 21).

[0017]

Table 1

[0018] Furthermore, by using a pair of rolls 2 each having an arcuate concave groove 21, as shown in FIG. 5, a roll 3 having a pattern-forming recess for adding functions such as anti-slip, marks, graduations, etc. to the surface is installed between the rolling rolls 1 for rolling and rib forming of the rolling mill and the pair of rolls 2. After performing a step of forming a convex pattern on the surface of the rib R of the joint reinforcing bar B by pressing down the rib R of the joint reinforcing bar B from both sides with the roll 3, by using the pair of rolls 2 to correct the twist generated in the joint reinforcing bar B, it is possible to prevent the convex pattern formed on the surface of the rib R of the joint reinforcing bar B from being crushed.

[0019] The joint reinforcing bar B whose twist is corrected by the pair of rolls 2 is conveyed to a cooling bed (both not shown) via a run-in roller, a braking plate, etc.

[0020] An example of the joint reinforcing bar B manufactured by the method for suppressing the twist of the joint reinforcing bar having this rib is shown in FIGS. 6(b1) to (b3). FIGS. 6(a1) to (a3) are conventional joint reinforcing bars. From FIG. 6, it was confirmed that the joint reinforcing bar B manufactured by the method for suppressing the twist of the joint reinforcing bar having this rib can correct the cross-sectional shape of the joint reinforcing bar B to a shape close to a perfect circle by using a roll 2 having an arcuate concave groove 21 having a width dimension W2 larger than the width dimension W of the rib R of the joint reinforcing bar B at the central portion in the width direction of the roll 2 and pressing both edge portions of the rib R from the radial direction.

[0021] The method for suppressing the twist of the joint reinforcing bar having this rib has the following effects. · It is possible to correct the twist generated in the joint reinforcing bar B having the rib R and reduce the twist. · The tension of the rib R is uniform and the bending reproduction accuracy is high. Therefore, high technology is not required for processing. • The step difference between the node S and rib R of the reinforcing bar B can be reduced (or eliminated), meaning the cross-sectional shape of the reinforcing bar B can be corrected to a shape close to a perfect circle, resulting in excellent rolling performance. This reduces processing time and allows for the use of automated processing machines. • The entire circumference of the reinforcing bar B with ribs R is rolled, resulting in a smooth surface without roughness. Even with high levels of Cu (which can cause roughness), high quality is maintained, and the appearance is good. Furthermore, the absence of burrs ensures high safety.

[0022] The method for suppressing twisting of reinforcing bars having ribs according to the present invention has been described above based on its embodiments. However, the present invention is not limited to the configuration described in the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability]

[0023] The method for suppressing twisting of ribbed reinforcing bars according to the present invention can be suitably used for manufacturing ribbed reinforcing bars because it can solve problems such as the absence of twisting along the entire length, poor transportability, and the tendency for surface roughness to occur. [Explanation of symbols]

[0024] 1. Rolling roll for forming sections and ribs 2 rolls 3 rolls B Reinforcement Bar R Rib Section S

Claims

1. A method for suppressing twisting of a reinforcing bar with ribs, wherein the reinforcing bar, which has formed nodes and ribs using rolling rolls for node and rib forming in a rolling mill, is plastically deformed using a pair of rolls installed downstream of the rolling mill, thereby correcting the twisting that occurs in the reinforcing bar. As a post-process to the step of forming the nodes and ribs with the aforementioned node and rib forming rolling rolls, the process includes using a pair of flat rolls installed downstream of the rolling mill, each roll having a cylindrical smooth outer surface and a width of 4.6 to 7.8 mm, which is larger than the width dimension of the rib of the node reinforcement, and equipped with an arc-shaped groove with a radius of curvature of 13.5 to 18.8 mm, to press down both edges of the rib of the node reinforcement from both radial directions, thereby correcting the twisting that occurs in the node reinforcement by applying plastic deformation to the center of the node reinforcement. A method for suppressing twisting of reinforcing bars having ribs, characterized by the above.

2. The method for suppressing twisting of a reinforcing bar with ribs according to claim 1, characterized in that it includes the step of installing a roll equipped with a pattern-forming recess between the rolling rolls for forming the nodes and ribs of the rolling mill and a pair of rolls, and pressing down on the ribs of the reinforcing bar from both sides with the roll to form a convex pattern on the surface of the ribs of the reinforcing bar.

Images