Steel bar manufacturing equipment, manufacturing method, and quality control method

Abstract

To facilitate the operation of passing a steel material through a main groove when the steel material is passed through the main grooves of a pair of rolls while being rolled to form a steel bar. [Solution] Main grooves are formed in the roll, lined up in the axial direction. Recesses for different identification markers are formed in each main groove. The pair of rolls are rotatably supported by a stand. To identify the main groove through which the steel material is to pass, the stand is guided by rails so that it can be moved in the axial direction, and the position of the stand is determined by an axial positioning device. The axial positioning device includes a plurality of spacers that can be arranged in the axial direction on one axial side of the stand, a spacer base on which the spacers are placed, and an axial pressure device that applies pressure to the stand so as to press the stand against the spacers from the other axial side of the stand. The axial dimension of the spacers is correlated to the pitch of the main grooves, being an integer multiple, making it easy to adjust the positions of the steel material and the main grooves.

Description

[Technical field]

[0001] The present invention relates to an apparatus, a method and a quality control method for manufacturing steel bars for reinforced concrete (hereinafter often abbreviated to "steel bars") used to reinforce various concrete structures. [Background technology]

[0002] Steel bars are used as a material to reinforce concrete in a variety of structures, from the foundations of houses to high-rise buildings and bridge piers. Deformed steel bars are bars with ribs or numerous nodes formed on the surface to improve adhesion to concrete. Details of the properties that ensure the strength of buildings are given in JIS G 3112. When steel bars are shipped to a customer, they are bundled together in bundles of a certain number of bars using wire or other materials. A label outlining the quality of the steel bars is then attached to each bundle. A steel inspection certificate detailing the quality of the steel bars is also provided to the customer separately from the label. The steel inspection certificate is a document that certifies the chemical composition and mechanical properties, etc. (hereinafter referred to as "information") of the steel bars. When the bars are bundled together, the quality of the steel bars can be ascertained by comparing the label with the steel inspection certificate. However, because each steel bar does not have information that links it to the steel inspection certificate, when the bundle is untied and the bars are separated into individual pieces, the quality information of the steel bars cannot be ascertained.

[0003] In order to resolve this situation, a quality control method was developed in which an identification mark is attached to each steel bar and this identification mark is recorded on the steel inspection certificate, making it possible to control the quality of steel bars on an individual basis (Patent Document 1).

[0004] Patent Document 1 discloses a pair of rolls for forming identification marks together with ribs and knots as steel bars. The pair of rolls is formed with a main groove through which a steel bar passes. A plurality of main grooves are formed at intervals in the axial direction of the rolls. Each main groove is formed with a recess that serves as a different identification mark. When steel bars are produced through a plurality of processes from the same melting operation (melting process), the steel bars are passed through one of the plurality of main grooves for the pair of rolls. When steel bars are produced from a melting operation different from the previous melting operation, the steel bars are passed through a different main groove. As a result, if the identification marks of the steel bars are different, it can be determined that they were produced from a different melting operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4637786 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned Patent Document 1 does not disclose a configuration for supporting the pair of rolls. Therefore, it is unclear how to adjust the positions of the steel material and the pair of rolls when passing the bar-shaped steel material through the main grooves, so as to facilitate the work of passing the steel material through different main grooves.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to facilitate the adjustment of the positions of a steel material and a pair of rolls. [Means for solving the problem]

[0008] And if it were easier to thread the steel through the main grooves, it would also be easier to pass different bars produced from the same melting operation through different main grooves and give them different identification numbers. A large number of steel bars are produced from the same melting operation. Patent Document 1 describes that steel bars produced from the same melting operation are passed through the same main groove for a pair of rolls. When a large number of steel bars are produced, the total production time is long, during which the main groove gradually wears out. As a result, the first steel bar produced and the last steel bar produced will have a certain degree of variation in mechanical properties, even though they pass through the same main groove and have the same identification number. The steel inspection certificate describes the quality of the steel bars randomly inspected. Each steel bar manufacturer has established its own production technology so as not to deviate from the range of the standard specified in the steel inspection certificate, even considering the variation in quality during production.

[0009] The lifespan of a structure often spans several decades, and steel bars play an important role in maintaining the strength of the structure. If the quality of steel bars could be guaranteed within a narrower range than the standard range specified in the steel inspection certificate, the strength of the structure would be easier to maintain. The inventor realized that even if steel bars are produced from the same melting process, the variation in quality of the steel bars can be reduced by passing each lot through a different main groove, and this led to the creation of the present invention.

[0010] The manufacturing apparatus for steel bars for reinforced concrete of the present invention includes a pair of rolls for rolling and passing a bar-shaped steel material through the rolls to form a steel bar and transfer an identification mark to the cylindrical surface of the steel bar, a stand for rotatably supporting the pair of rolls, a rail for guiding the stand so as to be movable in the axial direction of the rolls, and an axial positioning device for determining the position of the stand in the axial direction to specify a main groove through which the steel material passes. The pair of rolls has a plurality of main grooves that are continuous in the circumferential direction and spaced apart from each other in the axial direction, and at least two main grooves at different positions in the axial direction have recesses for different identification marks. The axial positioning device includes a plurality of spacers that can be arranged side by side in the axial direction on one side of the stand in the axial direction, a spacer base on which the spacers are placed, an axial pressure device for applying pressure to the stand from the other side of the axial direction relative to the stand so as to press the stand against the spacers, and a stopper for preventing the spacer furthest from the stand from moving to the one side in the axial direction. With regard to the dimension in the axial direction, the dimension of the spacer has a correlation with the pitch of the main grooves, being an integer multiple.

[0011] Integer multiples are, of course, positive integer multiples. In order to facilitate the work of adjusting the positions of the steel material and the main groove in the axial direction, it is desirable to do the following. The dimensions of the spacer should be equal to the pitch of the main grooves.

[0012] The number of rails is not important, but it is preferable to do the following to stabilize the position of the stand when moving it: That is, at least one pair of rails is provided, and the pair of rails is arranged with a gap between them on the upstream side and the downstream side in the traveling direction of the steel material.

[0013] When the stand is guided by a pair of rails spaced apart in the traveling direction, the stand is capable of slight movement in the traveling direction between the pair of rails. In such a case, in order to stably support the stand and produce higher quality steel bars, it is desirable to do the following. That is, the manufacturing apparatus for steel bars for reinforced concrete further comprises a traveling direction positioning device that determines the position of the stand that is capable of slight movement between the pair of rails in the traveling direction. The traveling direction positioning device comprises a pair of traveling direction pressure devices that are separately arranged on the upstream and downstream sides of the stand and cooperate to apply pressure to sandwich the stand.

[0014] It does not matter which part of the stand the pair of travel direction pressure devices pressurize, and the configuration may be such that they pressurize parts other than the parts guided by the rails, but it is preferable to do so as follows. That is, the stand comprises a bearing that supports the shaft portion of the roll, a stand body to which the bearing is fixed and which supports the roll via the bearing, and a pair of sliders that are fixed separately to the upstream surface facing the upstream side and the downstream surface facing the downstream side of the stand body and are guided in the axial direction by a pair of rails. The pair of rails comprise a pair of horizontal rail portions that separately support the lower surfaces of the pair of sliders from the upstream side and the downstream side in the traveling direction, and a pair of vertical rail portions that guide the pair of sliders so as to sandwich them from the upstream side and the downstream side in the traveling direction with a gap therebetween. Then, a pair of traveling direction pressure devices pressurize the pair of sliders.

[0015] The present invention also includes a method for manufacturing steel bars for reinforced concrete using the above-mentioned manufacturing apparatus for steel bars for reinforced concrete. In the method for manufacturing steel bars for reinforced concrete, when a plurality of steel bars are produced from the same melting operation, with each lot consisting of a plurality of steel bars, a spacer corresponding to the main groove through which the steel material is to pass is selected from a plurality of spacers, and the selected spacer is placed on a spacer stand, thereby passing the steel material through the main groove to which a different identification mark is attached for each lot.

[0016] The present invention also includes a quality control method for steel bars for concrete reinforcement. In the quality control method for steel bars for concrete reinforcement, a lot number is formed on the steel bars as a different identification mark for each lot by producing multiple lots of steel bars using a manufacturing method for steel bars for concrete reinforcement. Then, quality control information is created separately from the production of the steel bars, in which the lot number, molten steel number, and quality of the steel bars are associated and recorded. Then, by comparing the molten steel number and lot number in both the quality control information and the steel bars, it becomes possible to grasp the quality of each individual steel bar. Effect of the Invention

[0017] In the manufacturing device for steel bars for reinforced concrete of the present invention, the dimension of the spacer is correlated with the pitch of the main groove in an integer multiple with respect to the axial dimension, so by adjusting the number of spacers placed on the spacer base and pressing the stand against the spacer with the axial pressure device, the axial position of the stand (main groove) is determined and the main groove through which the steel material passes can be specified, which makes it easier to adjust the positions of the steel material and the main groove in the axial direction. Incidentally, if there are no spacers, the axial position of the stand would be adjusted using, for example, a scale indicating the axial length, so by adopting the present invention, it becomes easier to adjust the positions of the steel material and the main groove in the axial direction.

[0018] The manufacturing method of steel bars for reinforced concrete of the present invention uses manufacturing equipment for steel bars for reinforced concrete, so that when producing multiple lots of steel bars from the same melting operation, it becomes easy to adjust the positions of the steel material and the main groove in the axial direction when changing the main groove through which the steel material passes so that different identification marks are attached to the steel bars for each lot.

[0019] The quality control method for steel bars for concrete reinforcement according to the present invention makes it possible to grasp the quality of each individual steel bar by comparing lot numbers in both the quality control information and the steel bars. [Brief description of the drawings]

[0020] [Figure 1]1 is a front view showing a steel bar manufacturing apparatus according to a first embodiment of the present invention. FIG. [Diagram 2] FIG. 1 is a left side view showing a steel bar manufacturing apparatus according to a first embodiment. [Diagram 3] FIG. 1 is a plan view showing a steel bar manufacturing apparatus according to a first embodiment. [Figure 4] FIG. 2 is a plan view showing a steel bar manufacturing apparatus according to a first embodiment in which the number of spacers is reduced. [Diagram 5] 1A and 1B are a front view and a side view showing an example of a deformed steel bar. [Figure 6] An example of quality control information is shown below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Steel bars include round steel and deformed steel bars. FIG. 5 shows a deformed steel bar 1 as an example of steel bar 1. The deformed steel bar 1 includes a round bar-shaped steel bar body 2, a rib 3 as a protrusion that protrudes from the cylindrical surface of the steel bar body 2 and continues in the axial direction of the steel bar body 2, and a node 4 as a protrusion other than the axially continuing protrusion (rib 3) that protrudes from the cylindrical surface of the steel bar body 2. The node 4 is formed at a constant interval in the axial direction over the entire length in the axial direction. More specifically, in the deformed steel bar 1 in FIG. 5, there is a pair of ribs 3, which are arranged symmetrically with respect to the cylindrical surface of the steel bar body 2. The cylindrical surface of the steel bar body 2 is divided in two by the pair of ribs 3, and two semicircular curved surfaces are formed on the surface of the steel bar body 2. The node 4 protrudes from the two curved surfaces and is an arc extending in the circumferential direction while spanning the pair of ribs 3. In addition to the bar body 2, ribs 3, and sections 4, the deformed bar 1 also has an identification mark 5 attached to the cylindrical surface of the bar body 2. The identification mark 5 is a protrusion that protrudes from the cylindrical surface of the bar body 2. It is positioned between a pair of ribs 3 on the cylindrical surface of the bar body 2. In this embodiment, the identification mark 5 is a lot number. The lot number is made up of multiple characters.

[0022] As shown in Figures 1 to 3, a steel bar manufacturing apparatus according to a first embodiment of the present invention includes a pair of rolls 10 that finishes round bar-shaped steel material 1a into a steel bar 1, a stand 20 that rotatably supports the pair of rolls 10 in an opposing vertical position, and a rotation drive device 30 that synchronously drives and rotates the pair of rolls 10.

[0023] As shown in FIG. 1, the rotation drive device 30 includes a motor 31 as a drive source, a reducer 32 that reduces the rotation speed of the motor 31, and a pair of shaft couplings 33 that separately connect the reducer 32 and a pair of rolls 10 to transmit the rotation of the reducer 32.

[0024] The reducer 32 includes an input shaft 32a connected to the drive shaft 31a of the motor 31, two output shafts 32b connected to a pair of shaft couplings 33, and a reduction mechanism 32c that reduces the rotation of the input shaft 32a and transmits it to the two output shafts 32b.

[0025] Specifically, the roll 10 is a grooved roll. The roll 10 includes a cylindrical body 11 and a pair of shafts 12 extending from both end faces of the body 11. The axis L of the roll 10 is a straight line that is the center of the rotation of the roll 10, and coincides with the center line of the rotation of the body 11 and the center line of the rotation of the shafts 12. The direction in which the axis L extends is referred to as the "axial direction Y." The axial direction Y is horizontal.

[0026] A plurality of main grooves 13 are formed on the cylindrical surface of the body 11 at intervals in the axial direction Y. The pitch P of adjacent main grooves 13 is the same. The pitch P is the distance in the axial direction Y, and is the distance between the center of one of the adjacent main grooves 13 in the groove width direction (axial direction Y) and the center of the adjacent main groove 13 in the groove width direction. The multiple main grooves 13 are arranged at the same pitch P.

[0027] The main grooves 13 are for forming the curved surface of the steel bar body 2, and are formed around the entire circumference of the trunk portion 11, that is, continuously in the circumferential direction of the trunk portion 11. A hole is formed between a pair of main grooves 13 facing each other vertically to allow the steel material 1a to pass through. Hereinafter, the direction in which the steel material 1a advances relative to the pair of rolls 10 as shown in Figures 2 and 3 is referred to as the "advancement direction X". The advancement direction X is perpendicular to the axial direction Y in a plan view.

[0028] As shown in Fig. 1, the pair of rolls 10 are arranged vertically with a small gap therebetween. This gap forms a pair of ribs 3 of the deformed steel bar 1. A knot groove 14 for forming the knots 4 is recessed into each main groove 13. The knot grooves 14 are formed over the entire length of the main groove 13 in the groove width direction, and are arranged at intervals in the circumferential direction of the main groove 13. In this embodiment, a recess 15 for the identification mark 5 is formed in each main groove 13 of the roll 10. The recess 15 is formed to be recessed into the main groove 13. The recess 15 has an appearance that is an inverted version of the identification mark 5 (lot number). The recess 15 is pressed against the cylindrical surface of the steel bar body 2, whereby the identification mark 5 is transferred and formed.

[0029] When the stand 20 moves in the axial direction Y of the pair of rolls 10, the shaft coupling 33 transmits the rotation of the output shaft 32b of the reducer 32 to the shaft portion 12 of the rolls 10 regardless of the amount of movement. For example, a universal joint with a spline shaft is used for the shaft coupling 33. The output shaft 32b of the reducer 32 is connected to a connecting portion on one side of the universal joint 33, and the shaft portion 12 of one roll 10 is connected to a connecting portion on the other side of the universal joint 33.

[0030] In addition to the pair of rolls 10, the stand 20, and the rotation drive device 30, the bar steel manufacturing apparatus of the first embodiment also includes a floor plate 40, a pair of rails 50 arranged parallel to and spaced apart in the traveling direction X (upstream and downstream sides thereof) and movably guiding the stand 20 in the axial direction Y, an installation member 41 spanning the pair of rails 50, a steel material guide section 60 that guides the steel material 1a upstream of the pair of rolls 10, a steel bar guide section 65 that guides the steel bar 1 downstream of the pair of rolls 10, and an axial positioning device 70 that determines the position of the stand 20 in the axial direction Y in order to identify the main groove 13 through which the steel material 1a guided by the steel material guide section 60 passes.

[0031] A pair of rails 50 and a steel guide section 60 are fixed to the floor plate 40. An installation member 41 is fixed so as to span the ends of the pair of rails 50 on the same side at both ends in the axial direction Y. One of the pair of installation members 41 (the left side in Fig. 1) is detachably fixed to the pair of rails 50 with bolts. The installation member 41 is plate-shaped in the figure, and is fixed with its thickness direction aligned with the axial direction Y, pressed against the end faces of the pair of rails 50 on the same side on both sides in the axial direction Y.

[0032] 2, the steel material guide part 60 includes a post 61 extending upward from the floor plate 40, and a passing part 62 that is fixed to the upper part of the post 61 and allows the steel material 1a to pass through. The bar steel guide part 65 also includes a post 66 extending upward from the floor plate 40, and a passing part 67 that is fixed to the upper part of the post 66 and allows the bar steel 1 to pass through.

[0033] The stand 20 includes a bearing 21 that supports the shaft portion 12 of the roll 10, a stand body 22 to which the bearing 21 is fixed and which supports the roll 10 via the bearing 21, and a pair of sliders 27 that are fixed separately to the upstream surface facing the upstream side and the downstream surface facing the downstream side of the stand body 22 and are guided in the axial direction Y by a pair of rails 50. The bearing 21 supports the shaft portion 12 rotatably but immovably in the axial direction Y.

[0034] The stand main body 22 is provided with left and right support portions 23 that face each other at a distance in the axial direction Y and support the left and right sides of the upper and lower rolls 10 via bearings 21, and joint portions 24 that join the left and right support portions 23 above the upper roll 10 and below the lower roll 10.

[0035] The support portion 23 is a rectangular frame when viewed from the axial direction Y. A space portion 23s is formed inside the support portion 23, penetrating in the axial direction. The bearings 21 are arranged vertically side by side in the space portion 23s, and the upper and lower bearings 21 are fixed to the support portion 23. The bearings 21 are fixed symmetrically to the left and right support portions 23. In this embodiment, the support portion 23 is composed of an upper frame 23a and a lower frame 23b that extend in the traveling direction X and face each other vertically, and a pair of pillars 23c that extend in the vertical direction and face each other in the traveling direction X.

[0036] In this embodiment, the joint portion 24 is composed of four joint members 24a extending in the axial direction Y. Each joint member 24a is joined to the left and right support portions 23. As shown in FIG. 2, two of the joint members 24a are disposed below the lower roll 10 with a gap in the traveling direction X. As shown in FIG. 3, the remaining two joint members 24a are disposed above the upper roll 10 with a gap in the traveling direction X.

[0037] The pair of rails 50 includes a pair of horizontal rail portions 51 that separately support the lower surfaces of the pair of sliders 27 from the upstream and downstream sides in the traveling direction X, and a pair of vertical rail portions 52 that guide the pair of sliders 27 so as to sandwich them via a gap from the upstream and downstream sides in the traveling direction X. The vertical rail portions 52 are fixed onto the floor board 40. In this embodiment, when viewed from the axial direction Y, the rail 50 has the horizontal rail portions 51 protruding parallel to the traveling direction X from the vertically intermediate portions of the vertical rail portions 52 that extend in the vertical direction so as to support the lower surface of the stand 20. As shown in FIG. 3, a dimension 50L of the rail 50 in the axial direction Y is longer than a dimension 27L of the slider 27 in the axial direction Y. Hereinafter, for convenience, the rail 50 located relatively upstream may be referred to as the upstream rail 50 , and the rail 50 located relatively downstream may be referred to as the downstream rail 50 . The vertical rail portion 52 of the upstream rail 50 is disposed upstream of the upstream slider 27 with a small gap therebetween. The vertical rail portion 52 of the downstream rail 50 is disposed downstream of the downstream slider 27 with a small gap therebetween.

[0038] The slider 27 is fixed to the stand body 22 below the lower roll. In addition, for the pair of sliders 27, the slider 27 fixed to the upstream surface of the stand body 22 may be referred to as the upstream slider 27, and the slider 27 fixed to the downstream surface of the stand body 22 may be referred to as the downstream slider 27 for convenience. The slider 27 has a groove portion 28 that extends in the axial direction Y and opens in the direction opposite to or toward the traveling direction X. The groove portion 28 of the upstream slider 27 opens toward the vertical rail portion 52 of the upstream rail 50, and the groove portion 28 of the downstream slider 27 opens toward the vertical rail portion 52 of the downstream rail 50. The slider 27 is U-shaped when viewed from the axial direction Y.

[0039] The axial positioning device 70 includes a plurality of spacers 71 which can be arranged in a line in the axial direction Y on one side of the axial direction Y (left side in Figure 1) with respect to the stand 20, a spacer base 72 on which the spacers 71 are placed, an axial pressure device 73 which applies pressure to the stand 20 from the other side of the axial direction Y (right side in Figure 1) to press the stand 20 against the spacers 71, and a stopper S which prevents the spacer 71 which is farthest from the stand 20 from moving to one side of the axial direction Y (right side in Figure 1).

[0040] In this embodiment, the spacer base 72 also serves as the vertical rail portion 52 .

[0041] The stopper S is fixed to one side (left side) of the pair of vertical rail portions 52 in the axial direction Y. In this embodiment, the stopper S also serves as a part of the installation member 41. The stopper S is disposed at a position where it overlaps at least a part of the spacer 71 placed on the vertical rail portion 52 (spacer base 72) when viewed from the axial direction Y.

[0042] The spacer 71 includes a placement portion 71a to be placed on the spacer base 72 (vertical rail portion 52), and a contact portion 71b that is capable of contacting the stand 20 or the stopper S and restricting movement in one direction in the axial direction Y. In this embodiment, the spacer 71 is L-shaped when viewed from the axial direction Y, and the contact portion 71b is continuous with the placement portion 71a while bending downward. Furthermore, if the spacer 71 includes a permanent magnet in a part thereof and the spacer base 72 is made of a material to which a permanent magnet is attracted, the spacer 71 will be less likely to fall during attachment / detachment of the spacer 71, making the attachment / detachment operation easier.

[0043] Of the spacers 71 placed on the spacer base 72, the spacer 71 that is furthest in the axial direction Y from the stand 20 comes into contact with the stopper S. On the other hand, of the spacers 71 placed on the spacer base 72, the spacer 71 that is closest in the axial direction Y from the stand 20 comes into contact with the stand 20. Incidentally, there are six spacers 71 placed on the spacer base 72 in Figs. 1 and 3, and the spacer 71 located on the leftmost side in each drawing is the spacer 71 that is furthest in the axial direction Y from the stand 20, and the spacer 71 located on the rightmost side in each drawing is the spacer 71 that is closest in the axial direction Y to the stand 20. Also, in Fig. 4, there is only one spacer 71 placed on the spacer base 72, and this one spacer 71 is the spacer 71 that is furthest in the axial direction Y from the stand 20 and is also the spacer 71 that is closest in the axial direction Y to the stand 20.

[0044] As shown in Fig. 1, the dimension W of the spacer 71 in the axial direction Y is correlated to the pitch P of the main grooves 13, being an integer multiple. In this embodiment, the dimension W of each spacer 71 in the axial direction Y is the same as the pitch P of the main grooves 13. When the same number of spacers 71 as the total number of the main grooves 13 formed in the roll 10 are placed on the spacer base 72, the steel material 1a is set to pass through the main groove 13 at the end on one side (left side) in the axial direction Y of the main grooves 13 formed in the roll 10, and when only one spacer 71 is placed on the spacer base 72, the steel material 1a is set to pass through the main groove 13 at the end on the other side (right side) in the axial direction Y of the main grooves 13 formed in the roll 10.

[0045] The axial pressure device 73 is an actuator, and in this embodiment, is a hydraulic cylinder 73. The axial pressure device 73 is installed on the other side of the stand 20 in the axial direction Y. A piston rod 74 of the hydraulic cylinder 73 reciprocates in the axial direction Y, and a tip of the piston rod 74 is fixed to the stand 20. A cylinder 75 of the hydraulic cylinder 73 is installed in an immobile state.

[0046] 2 and 3, the steel bar manufacturing apparatus of the first embodiment is equipped with a traveling direction positioning device 80 that determines the position of the stand 20, which is finely movable between the pair of rails 50, in the traveling direction X. The traveling direction positioning device 80 is equipped with two pairs of traveling direction pressure devices 81 that are separately arranged on the upstream and downstream sides of the stand 20 and cooperate to pressurize the stand 20 in a sandwiching manner.

[0047] The travel direction pressure device 81 is an actuator, which is a hydraulic cylinder 81 in this embodiment. A cylinder 82 of the hydraulic cylinder 81 is fixed to the vertical rail portion 52. A piston rod 83 of the hydraulic cylinder 81 is disposed so as to protrude from the vertical rail portion 52 toward the groove portion 28 of the slider 27. A hole 52h through which the piston rod 83 passes is formed in the vertical rail portion 52 so as to penetrate in the travel direction.

[0048] The tip of the piston rod 83 is a pressurizing portion 84 that pressurizes the groove portion 28. The pressurizing surface of the pressurizing portion 84 and the pressurized surface of the groove portion 28 are formed so that the pressure applied from the pressurizing portion 84 to the groove portion 28 can be dispersed into a pressure acting horizontally so as to sandwich the stand 20, and a downward pressure acting to press the stand 20 downward. Specifically, the pressurizing surface of the pressurizing portion 84 and the pressurized surface of the groove portion 28 each have a lateral surface 84a, 28a and a lower surface 84b, 28b. The lower surface 84b of the pressurizing portion 84 and the lower surface 28b of the groove face each other in the vertical direction and can be in close contact with each other. On the other hand, the lateral surface 84a of the pressurizing portion 84 and the lateral surface 28a of the groove portion 28 face each other in the horizontal direction, and face each other with a gap therebetween when the lower surface 84b of the pressurizing portion 84 and the lower surface 28b of the groove are in close contact with each other. The lower surface 84b of the pressure applying portion 84 and the lower surface 28b of the groove portion 28 are inclined relative to the horizontal plane. The lower surface 28b of the groove portion 28 is inclined downward toward the inlet side of the groove portion 28. The lower surface 84b of the pressure applying portion 84 is inclined upward toward the opposing groove portion 28. The lateral surface 84a of the pressure applying portion 84 and the lateral surface 28a of the groove portion 28 are planes perpendicular to the traveling direction.

[0049] The steel bar 1 is manufactured as follows using the steel bar manufacturing apparatus of the first embodiment. Before processing with the steel bar manufacturing apparatus of the first embodiment, the steel material 1a is formed in a rolling process so that the cross section is suitable for the steel bar 1, in this case, elliptical. Then, it is decided which of the six main grooves 13 arranged in the axial direction Y the steel material 1a will be passed through for the tip of the bar-shaped steel material 1a having an elliptical cross section. For example, the left-right direction in Figs. 1 and 3 coincides with the axial direction Y. It is decided to pass the steel material 1a through the main groove 13 on the leftmost side in Figs. 1 and 3 for rolling. In this case, the same number of spacers 71 as the total number of main grooves 13 are placed on the spacer base 72. Then, when the axial pressure device 73 is driven to move the piston rod 74 forward, the stand 20 is guided by the pair of rails 50 and moves toward the spacers 71, and the six spacers 71 are pushed through the stand 20 by the axial pressure device 73. The spacer 71 farthest from the stand 20 (the leftmost spacer 71) is pressed against the stopper S to restrict its movement. As a result, the stand 20 is sandwiched and positioned between the multiple spacers 71 and the axial pressure device 73, and the positions of the passing portion 62, the passing portion 67, and the leftmost main groove 13 in the axial direction Y coincide with each other, and the steel material 1a is set to pass through the leftmost main groove 13. Next, two pairs of the forward pressure devices 81 are driven, the piston rod 83 is advanced for each forward pressure device 81, and the tip of the piston rod 83 presses the groove portion 28 of the slider 27. Then, the stand 20 is positioned in the axial direction Y and pressed downward. In this state, the steel material 1a is passed through the main groove 13, the motor 31 is driven, and the pair of rolls 10 is rotated. By doing so, the identification mark 5 is transferred to the cylindrical surface of the steel bar 1. The steel material 1a is passed between the pair of rolls 10 by the length required for one lot. The steel bar 1 that has passed through a pair of rolls 10 is cut to the length required for shipping, and a set number of bars are bundled together into one lot.

[0050] Also, when it is desired to use another main groove 13, for example, when passing the steel material 1a through the rightmost main groove 13 as shown in FIG. 4, two pairs of the forward pressure devices 81 are driven to move the piston rod 83 backward, forming a gap between the pair of vertical rail parts 52 and the pair of sliders 27 that allows slight movement, and the stand 20 is made slightly movable in the axial direction Y on the pair of rails 50. Next, the axial pressure device 73 is driven to move the piston rod 74 backward, and the stand 20 together with the pair of rolls 10 is moved away from the spacer 71. Then, one spacer 71 is placed on the spacer base 72. Next, the axial pressure device 73 is driven in the same manner as above to move the piston rod 74 forward, and the stand 20 is positioned in the axial direction Y. Also, two pairs of the forward pressure devices 81 are driven to move the piston rod 83 forward, and the stand 20 is positioned in the axial direction Y. As a result, the positions in the axial direction Y of the passing portion 62, the passing portion 67 and the rightmost main groove 13 coincide with each other, and the steel material 1a is set to pass through the rightmost main groove 13.

[0051] In the steel bar manufacturing apparatus of the first embodiment, since the dimension W of the spacer 71 is correlated with the pitch P of the main groove 13 as an example of an integer multiple, 1 (same multiple), with respect to the dimension in the axial direction Y, by adjusting the number of spacers 71 placed on the spacer base 72 and pressing the stand 20 against the spacer 71 with the axial pressure device 73, the position in the axial direction Y of the stand 20 (main groove 13) is determined, and the main groove 13 through which the steel material 1a passes can be specified, which makes it easier to adjust the positions of the steel material 1a and the main groove 13 with respect to the axial direction Y. Also, since the dimension W of the spacer 71 is correlated with the pitch P of the main groove 13 as an example of an integer multiple, 1, it is easy to grasp the axial positional relationship between the number of spacers 71 placed on the spacer base 72 and the main groove 13 through which the steel material 1a passes. Moreover, even if the same number of spacers 71 as the total number of main grooves 13 (specifically, six) are placed on the spacer base 72, the main groove 13 through which the steel material 1a passes can be identified, making it easier to adjust the positions of the steel material 1a and the main grooves 13 in the axial direction Y.

[0052] Thus, according to the method for manufacturing steel bars using the steel bar manufacturing apparatus of the first embodiment, when multiple lots of steel bars 1 are produced from the same melting operation under the condition that one lot consists of multiple steel bars 1, it is possible to pass the steel material 1a through the main groove 13 to which a different identification mark 5 is attached for each lot by selecting a spacer 71 from the multiple spacers 71 that corresponds to the main groove 13 through which the steel material 1a is to pass and placing the selected spacer 71 on the spacer base 72. Then, in the operation of changing the main groove 13 through which the steel material 1a is to pass, the operation of adjusting the positions of the steel material 1a and the main groove 13 in relation to the axial direction Y becomes easy.

[0053] The above-mentioned manufacturing method allows the quality control of steel bars to be performed as follows. By producing multiple lots of steel bars 1, a lot number is formed as a different identification mark 5 on the steel bars 1 for each lot. As shown in FIG. 6, quality control information is created in which the lot number of the steel bars, the molten steel number, and the quality are associated with each other. The quality control information is a table in which, in addition to the molten steel number and lot number, information such as the mechanical properties of the steel bars in tensile tests and bending tests, the chemical composition of the steel bars, and the diameter and length of the steel bars are recorded. Although the steel inspection certificate does not include the lot number, the quality control information includes more detailed information than the steel inspection certificate. In this way, by comparing the lot numbers in both the quality control information and the steel bars, it is possible to grasp the quality of each steel bar. Incidentally, in FIG. 6, three different lot numbers are listed for one molten steel number. In FIG. 6, the mechanical properties, chemical composition, and other information of the steel bars are omitted, but the information of the steel bars corresponding to the lot number is listed. In this way, even with one molten steel number, unique information can be managed for each lot. The quality control information differs from the steel inspection certificates (which contain information other than the lot number) that have traditionally been submitted to customers in that it contains the lot number and molten steel number, and is information managed independently by the manufacturer.

[0054] The present invention is not limited to the above embodiment, and can be modified as appropriate within the scope of the present invention. For example, in the present embodiment, the stopper S and one spacer 71 are separate parts in the bar steel manufacturing device, but the present invention is not limited to this, and the stopper S may also serve as one spacer 71. In addition, in the present embodiment, all main grooves 13 formed in the roll 10 are formed with recesses 15 that serve as different identification marks, but the present invention is not limited to this, and as long as recesses 15 that serve as different identification marks are formed in at least two of all main grooves 13 formed in the roll 10, recesses 15 that serve as the same identification mark may be included. In addition, in the present embodiment, the rail 50, the steel material guide portion 60, the bar steel guide portion 65, etc. are fixed to the floor plate 40, but the present invention is not limited to this, and the floor plate 40 is not required, and the main grooves 13 may be fixed directly to another object, for example, the floor. [Explanation of symbols]

[0055] 1 Steel bar (deformed steel bar) 1a Steel material 2. Steel bar body 3. Ribs Verse 4 5. Identification signs 10 rolls 11. Torso 12 Shaft 13 Main groove 14 Nodal groove 15 Recess 20 Stand 21 Bearings 22 Stand body 23 Support part 23a Upper stile 23b Lower stile 23c pillar 23s space part 24 Joint 24a Joint material 27 Slider 27L Axial dimension of slider 28 Groove 28a Lateral plane 28b Bottom side 30 Rotational drive unit 31 Motor 31a Driving shaft 32 Reducer 32a Input shaft 32b Output shaft 32c Reduction mechanism section 33 Shaft joint (universal joint) 40 Floorboards 41 Construction members 50 Rail 50L Rail axial dimension 51 Horizontal rail section 52 Vertical rail section 52h hole 60 Steel guide section 61 Posts 62 Passage section 65 Steel bar guide section 66 Posts 67 Passage section 70 Axial positioning device 71 Maza 71a Placement part 71b Contact part 72 Pavilion stand 73 Axial pressure device (hydraulic cylinder) 74 Piston rod 75 cylinders 80 Positioning device for direction of travel 81 Pressure device for forward direction (hydraulic cylinder) 82 cylinders 83 Piston rod 84 Pressurizing section 84a Lateral plane 84b Bottom surface L axis Pitch S stopper X Direction of travel Y axis direction W dimension

Claims

1. The present invention comprises a pair of rolls which roll and pass a bar-shaped steel material through the pair of rolls to form a steel bar and transfer an identification mark onto the cylindrical surface of the steel bar, the pair of rolls having a plurality of circumferentially continuous main grooves formed at intervals in the axial direction of the pair of rolls and at least two main grooves at different positions in the axial direction having recesses for different identification marks, a stand which rotatably supports the pair of rolls, a rail which guides the stand so that the stand can move in the axial direction, and an axial positioning device which determines the position of the stand with respect to the axial direction in order to specify the main groove through which the steel material is to pass, The axial positioning device includes a plurality of spacers that can be arranged in a line in the axial direction on one axial side of the stand, a spacer base on which the spacers are placed, an axial pressure device that applies pressure to the stand from the other axial side of the stand so as to press the stand against the spacers, and a stopper that prevents the spacer farthest from the stand from moving to the one axial side, 1. An apparatus for manufacturing steel bars for reinforced concrete, characterized in that, with respect to the axial dimension, the dimension of the spacer has a correlation with the pitch of the main grooves such that the dimension is an integer multiple of the pitch of the main grooves.

2. 2. The manufacturing apparatus for steel bars for reinforced concrete according to claim 1, wherein the dimension of the spacer is correlated to the pitch of the main groove so as to be equal to the pitch of the main groove.

3. In a method for producing steel bars using the apparatus for producing steel bars for concrete reinforcement according to claim 1 or 2, A manufacturing method for steel bars for reinforced concrete, characterized in that when producing multiple lots of steel bars from the same melting operation under the condition that one lot consists of multiple steel bars, a spacer corresponding to the main groove through which the steel material is to pass is selected from a plurality of spacers, and the selected spacer is placed on a spacer stand, thereby allowing the steel material to pass through a main groove marked with a different identification mark for each lot.

4. By producing a plurality of lots of steel bars using the method for producing steel bars for concrete reinforcement according to claim 3, a lot number is formed as a different identification mark on the steel bars for each lot, Creating quality control information in which the lot number of the steel bar, the molten steel number, and the quality are associated and recorded; A quality control method for steel bars for reinforced concrete, characterized in that it is possible to grasp the quality of each individual steel bar by comparing lot numbers in both quality control information and the steel bars.

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