Channel steel

Abstract

To achieve further weight reduction while suppressing a decrease in a load that can be supported.SOLUTION: A channel steel 10 includes one flange 20 and the other flange 22 extending along each other and a web 24. The web 24 is connected to one end of one flange 20 and one end of the other flange 22 to form an internal space 30 together with one flange 20 and the other flange 22. The web 24 runs along one flange 20 and the other flange 22. A limit improvement area is provided on either one opposing surface 40 or the other opposing surface 44. One opposing surface 40 is an area of one flange 20 that faces the internal space 30. The other opposing surface 44 is an area of the other flange 22 that faces the internal space 30. The limit improvement area is an area having a higher elastic limit than areas of one flange 20 and the other flange 22 that are on a rear side of the limit improvement area.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to channel steel.

Background Art

[0002] Patent Document 1 discloses channel steel. This channel steel has a cross-sectional shape in which the flange portion has a double, triple, or more overlapping structure by hemming and folding processing.

[0003] The channel steel disclosed in Patent Document 1 can increase the second moment of area, etc. even with the same weight and the same outer dimensions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the channel steel disclosed in Patent Document 1 has a problem that further weight reduction is difficult.

[0006] The present invention solves such problems. Its object is to provide channel steel that can achieve further weight reduction while suppressing a decrease in the load that can be supported.

Means for Solving the Problems

[0007] The channel steel of the present invention will be described with reference to the drawings. Note that the use of reference numerals in the drawings in this section is for helping the understanding of the content of the invention and is not intended to limit the content to the illustrated range.

[0008] To solve the above-described problems, according to an aspect of the present invention, the channel steel 10 includes a pair of flanges 20, 22 extending along each other and a web 24. The web 24 is connected to one end of one of the pair of flanges 20, 22 and the other end of the other of the pair of flanges 20, 22 to form an inner space 30 together with the pair of flanges 20, 22. The web 24 extends along the pair of flanges 20, 22. Limit improvement regions 60, 62, 80, 82 are provided on either one of the one opposing surface 40 and the other opposing surface 44. The one opposing surface 40 faces the inner space 30 of one of the pair of flanges 20, 22. The other opposing surface 44 faces the inner space 30 of the other of the pair of flanges 20, 22. The limit improvement regions 60, 62, 80, 82 are regions having a larger elastic limit than the regions corresponding to the back sides of the limit improvement regions 60, 62, 80, 82 among the flanges 20, 22 where the limit improvement regions 60, 62, 80, 82 are provided.

[0009] Providing the limit improvement regions 60, 62, 80, 82 in the portions of the flanges 20, 22 facing the inner space 30 leads to suppressing a decrease in the elastic limit, similar to the case where the thickness of the location where the limit improvement regions 60, 62, 80, 82 are provided is thick. Suppressing the decrease in the elastic limit in this way means that the thickness of the flanges 20, 22 can be reduced while suppressing a decrease in the load that can be supported. Being able to reduce the thickness means that further weight reduction can be achieved while suppressing a decrease in the load that can be supported. Thus, when the limit improvement regions 60, 62, 80, 82 are provided in the portions of the flanges 20, 22 facing the inner space 30, it becomes possible to achieve further weight reduction while suppressing a decrease in the load that can be supported.

[0010] Moreover, it is desirable that any one of the above-described limit improvement regions 60, 62, 80, 82 is arranged to be in contact with the location where the flanges 20, 22 and the web 24 are connected.

[0011] By the limiting improvement regions 60 and 80 being in contact with the portions where the flanges 20 and 22 are continuous with the web 24, it becomes easy to form the limiting improvement regions 60 and 80 in conjunction with the formation of the portions where the flanges 20 and 22 are continuous with the web 24. Thereby, productivity can be improved.

[0012] Also, it is desirable that the residual stress in any of the above-described limiting improvement regions 60, 62, 80, and 82 is compressive stress.

[0013] When tensile stress is applied in some form to the limiting improvement regions 60, 62, 80, and 82 where the residual stress is compressive stress, the influence of the tensile stress is mitigated by the residual stress which is compressive stress. Since the influence is mitigated, the load that the channel steel 10 according to a certain aspect of the present invention can support increases accordingly.

Advantages of the Invention

[0014] According to the channel steel according to the present invention, further weight reduction can be achieved while suppressing a decrease in the load that can be supported.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0017] [Description of the Configuration] FIG. 1 is a conceptual diagram showing the configuration of a lip channel steel 10 according to the present embodiment. Based on FIG. 1, the configuration of the lip channel steel 10 according to the present embodiment will be described.

[0018] The lip groove-shaped steel 10 according to this embodiment includes one flange 20, the other flange 22, the web 24, one lip 26, and the other lip 28.

[0019] As is clear from FIG. 1, the one flange 20 and the other flange 22 extend along each other. The web 24 is connected to one end of the one flange 20 and one end of the other flange 22. The web 24 extends along the direction in which the one flange 20 and the other flange 22 extend.

[0020] In the case of this embodiment, the one lip 26 is connected to the other end of the one flange 20. In the case of this embodiment, the one lip 26 protrudes toward the other flange 22. In the case of this embodiment, the other lip 28 is connected to the other end of the other flange 22. In the case of this embodiment, the other lip 28 protrudes toward the one flange 20. As a result, the one lip 26 and the other lip 28 face each other.

[0021] The space surrounded by the one flange 20, the other flange 22, and the web 24 is the inner space 30 according to this embodiment. As a result, the inner space 30 is formed by the one flange 20, the other flange 22, and the web 24. In the case of this embodiment, the surface of the one flange 20 facing the inner space 30 described above is the one facing surface 40. The surface of the one flange 20 on the back side of the one facing surface 40 is the one outer peripheral surface 42. The surface of the other flange 22 facing the inner space 30 described above is the other facing surface 44. The surface of the other flange 22 on the back side of the other facing surface 44 is the other outer peripheral surface 46. The surface of the web 24 facing the inner space 30 described above is the web facing surface 48. The surface of the web 24 on the back side of the web facing surface 48 is the web outer peripheral surface 50.

[0022] FIG. 2 is a cross-sectional view of the lip groove-shaped steel 10 according to this embodiment. Based on FIG. 2, the facing surfaces according to this embodiment are specifically described.

[0023] In the case of this embodiment, one opposing surface 40 has a one limit improvement region 60 on one end side, a one limit improvement region 62 on the other end side, and a one low improvement region 64. The one limit improvement region 60 on one end side is arranged at a position in contact with the portion described below on the one opposing surface 40. That portion is the portion where the one flange 20 and the web 24 are continuous. In the case of this embodiment, that portion forms a curved surface. The one limit improvement region 62 on the other end side is arranged at a position in contact with the portion described below on the one opposing surface 40. That portion is the portion where the one flange 20 and the one lip 26 are continuous. In the case of this embodiment, that portion also forms a curved surface. The one low improvement region 64 is arranged so as to be sandwiched between the one limit improvement region 60 on one end side and the one limit improvement region 62 on the other end side.

[0024] In the case of this embodiment, the one limit improvement region 60 on one end side and the one limit improvement region 62 on the other end side are regions where large permanent strains have occurred. Due to the occurrence of such permanent strains, the elastic limit of the one limit improvement region 60 on one end side is larger than the elastic limit of the region corresponding to the back side of the one limit improvement region 60 on the one outer peripheral surface 42. Similarly, the elastic limit of the one limit improvement region 62 on the other end side is larger than the elastic limit of the region corresponding to the back side of the one limit improvement region 62 on the one outer peripheral surface 42.

[0025] On the other hand, in the case of this embodiment, almost no permanent strain has occurred in the one low improvement region 64. Therefore, the elastic limit of the one low improvement region 64 is substantially the same as the elastic limit of the region corresponding to the back side of the one low improvement region 64 on the one outer peripheral surface 42.

[0026] In the case of this embodiment, the other opposing surface 44 has an other limit upward region 80 at one end side, an other limit upward region 82 at the other end side, and an other low upward region 84. The other limit upward region 80 at one end side is arranged at a position in contact with the location described below on the other opposing surface 44. That location is where the other flange 22 and the web 24 are continuous. In the case of this embodiment, that location forms a curved surface. The other limit upward region 82 at the other end side is arranged at a position in contact with the location described below on the other opposing surface 44. That location is where the other flange 22 and the other lip 28 are continuous. In the case of this embodiment, that location also forms a curved surface. The other low upward region 84 is arranged so as to be sandwiched between the other limit upward region 80 at one end side and the other limit upward region 82 at the other end side.

[0027] In the case of this embodiment, the other limit upward region 80 at one end side and the other limit upward region 82 at the other end side are regions where large permanent strains have occurred. Due to the occurrence of such permanent strains, the elastic limit of the other limit upward region 80 at one end side is larger than the elastic limit of the region corresponding to the back side of the other limit upward region 80 on the other outer peripheral surface 46. Similarly, the elastic limit of the other limit upward region 82 at the other end side is larger than the elastic limit of the region corresponding to the back side of the other limit upward region 82 on the one outer peripheral surface 42.

[0028] On the other hand, in the case of this embodiment, almost no permanent strain has occurred in the other low upward region 84. Therefore, the elastic limit of the other low upward region 84 is generally the same as the elastic limit of the region corresponding to the back side of the other low upward region 84 on the other outer peripheral surface 46.

[0029] Note that, in the case of this embodiment, the one limit upward region 60 at one end side, the one limit upward region 62 at the other end side, the other limit upward region 80 at one end side, and the other limit upward region 82 at the other end side are collectively referred to as "limit upward regions".

[0030] [Explanation of manufacturing method] The lip groove-shaped steel 10 according to this embodiment is manufactured by the following procedure. First, the steel plate used as the material is bent so that the part that will become one flange 20 and the part that will become the other flange 22 rise from the part that will become the web 24. Next, the part corresponding to the tip among the raised parts is bent so as to fall toward each other. These parts corresponding to the tips become one lip 26 and the other lip 28. These bends are realized by well-known means. Therefore, the details thereof will not be particularly described.

[0031] The member formed by the above-described bends is further plastically processed so that each part has a predetermined dimension. The plastic processing is realized by well-known means. Therefore, the details thereof will not be particularly described.

[0032] In the case of this embodiment, plastic processing for forming a limit improvement area is performed in parallel with the plastic processing for making each part of the member formed by the above-described bends have a predetermined dimension.

[0033] The plastic processing in this embodiment is to strongly cold-roll the part where the limit improvement area is to be formed with a well-known roller. By performing such cold rolling in parallel with the plastic processing for making each part have a predetermined dimension, the residual stresses in one limit improvement area 60 on one end side and one limit improvement area 62 on the other end side, and the residual stresses in the other limit improvement area 80 on one end side and the other limit improvement area 82 on the other end side all become compressive stresses.

[0034] In the case of this embodiment, the rollers for the above-described cold rolling are also served as the rollers described below. Those rollers are the roller that forms the location that becomes the boundary between one lip 26 and one flange 20, the roller that forms the location that becomes the boundary between one flange 20 and the web 24, the roller that forms the location that becomes the boundary between the other lip 28 and the other flange 22, and the roller that forms the location that becomes the boundary between the other flange 22 and the web 24.

[0035] When the cold rolling described above is performed in parallel with the plastic working to make each part have a predetermined dimension, the members subjected to those processes are painted. The specific details of the painting are the same as those well known. Therefore, the detailed description thereof will not be repeated here. When the painting is completed, the lip channel steel 10 according to the present embodiment is completed.

[0036] [Description of Effects] When the lip channel steel 10 according to the present embodiment receives a load, the limit improvement area also receives the stress caused by the load together with other parts. The limit improvement area is an area having a larger elastic limit than the area corresponding to the back side of those limit improvement areas. By providing the limit improvement area, the thicknesses of one flange 20 and the other flange 22 can be reduced. The fact that the thickness can be reduced means that further weight reduction can be achieved while suppressing a decrease in the elastic limit. Thereby, the lip channel steel 10 according to the present embodiment can achieve further weight reduction while suppressing a decrease in the load that can be supported.

[0037] Further, in the lip channel steel 10 according to the present embodiment, the limit improvement area is arranged so as to be in contact with the location where one flange 20 and the web 24 are continuous and the location where the other flange 22 and the web 24 are continuous. Thereby, it becomes easy to form the limit improvement area in combination with the formation of the location where one flange 20 and the web 24 are continuous and the formation of the location where the other flange 22 and the web 24 are continuous. Similarly, the limit improvement area is arranged so as to be in contact with the location where one flange 20 and one lip 26 are continuous and the location where the other flange 22 and the other lip 28 are continuous. Thereby, it becomes easy to form the limit improvement area in combination with the formation of the location where one flange 20 and one lip 26 are continuous and the formation of the location where the other flange 22 and the other lip 28 are continuous. As a result, productivity can be improved.

[0038] In addition, in the lip channel steel 10 according to the present embodiment, the residual stress in the limit improvement region is compressive stress. As a result, when tensile stress is applied to those limit improvement regions in some form, the influence of the tensile stress is mitigated by the residual stress which is compressive stress. Since the influence is mitigated, the load that the lip channel steel 10 according to the present embodiment can support increases accordingly.

[0039] The embodiments disclosed this time are illustrative in all respects. The scope of the present invention is not limited based on the above-described embodiments. Of course, various design changes may be made without departing from the spirit of the present invention.

[0040] For example, the number and arrangement of the limit improvement regions that the lip channel steel 10 has are not limited to those described above. The specific form of the limit improvement regions is also not limited to those described above. For example, the limit improvement regions may be formed by a well-known surface treatment such as nitriding treatment.

[0041] In addition, the channel steel according to the present invention is not limited to the lip channel steel 10. The channel steel according to the present invention may be a channel steel without a lip.

[0042] 10... Lip channel steel 20... One flange 22... The other flange 24... Web 26... One lip 28... The other lip 40... One opposing surface 42... One outer peripheral surface 44... The other opposing surface 46... The other outer peripheral surface 60... One limit improvement region on one end side 62... One limit improvement region on the other end side 64... One low improvement region 80... The other limit improvement region on one end side 82... The other limit improvement region on the other end side 84... The other low improvement region

Claims

1. A pair of flanges extending along each other, and a web, wherein the web is connected to one end of one of the pair of flanges and the other end of the other of the pair of flanges to form an inner space together with the pair of flanges, and along the pair of flanges, a limit improvement area is provided on either one of the one opposing surface of one of the pair of flanges facing the inner space and the other opposing surface of the other of the pair of flanges facing the inner space, the limit improvement area is an area having a larger elastic limit than the area corresponding to the back side of the limit improvement area among the flanges where the limit improvement area is provided, characterized by a channel steel.

2. The channel steel according to claim 1, wherein any one of the limit improvement areas is arranged to be in contact with the location where the flange and the web are connected.

3. The channel steel according to claim 1, wherein the residual stress in any one of the limit improvement areas is a compressive stress.

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