JP6753316B2 - Shaped steel manufacturing equipment and shaped steel manufacturing method - Google Patents

Description

The present invention relates to a shaped steel manufacturing facility and a shaped steel manufacturing method.

In the production line by hot rolling of shaped steel represented by H-shaped steel, a hot saw cutting machine that cuts the shaped steel in the width direction is installed at the end of the rolling line, etc., and the rolled shaped steel is rolled. Cutting is performed at a predetermined position. When cutting the shaped steel, a method of cutting the shaped steel in the width direction is adopted by rotating a circular saw blade arranged in a direction orthogonal to the transport line direction.

When cutting shaped steel with a circular saw blade, the temperature of the cut part of the shaped steel is set in order to prevent the life of the circular saw blade from shortening and the production line from stopping due to replacement of the circular saw blade. It is preferable to keep the temperature above. Therefore, normally, the shaped steel after hot rolling is hot sawed while being kept at a high temperature, but when the temperature drops, the cut portion of the shaped steel is heated by an induction heating coil, a torch, or the like. It has been proposed to heat by means. For example, Patent Document 1 below discloses a technique for heating the entire outer periphery of a shaped steel using an induction heating coil that matches the shape profile of the shaped steel, and Patent Document 2 below discloses a plurality of techniques. A technique for heating a shaped steel using an induction heating coil is disclosed.

By the way, in recent years, the specifications required for shaped steels, especially the specifications related to mechanical properties, have gradually become stricter, and for the purpose of improving performance, the structure of the material is controlled by water cooling during rolling. The proportion of TMCP (Thermo Mechanical Control Process) materials is increasing. Therefore, Patent Document 3 below discloses a technique for heating a cut portion by using a torch as a heating means when cutting a TMCP material whose strength has increased due to a decrease in temperature.

Japanese Unexamined Patent Publication No. 63-139609 Japanese Unexamined Patent Publication No. 51-150134 JP-A-2009-248270

However, the techniques disclosed in Patent Documents 1 and 2 are premised on heating a shaped steel formed into a desired shape offline. Therefore, when the techniques disclosed in Patent Documents 1 and 2 are applied to the production line of shaped steel by TMCP, interference between the conveying means such as the conveying roll and the induction heating coil becomes a problem. It cannot be applied as it is.

Further, in Patent Document 1 and Patent Document 2, an induction heating coil is arranged around the shaped steel at the cutting site, but in the section steel production line by TMCP, the rolled shaped steel is water-cooled. At this time, the rolled shaped steel is conveyed and water-cooled with the web surface of the web facing up and down, so that the cooling remaining on the surface of the shaped steel, particularly the web surface on the upper side of the web. Water may get caught in the induction heating coil or the energizing equipment during the cutting process, causing electric leakage or the like.

Further, in the technique disclosed in Patent Document 3, a torch is used as a heating means, but when rolling oil or the like used in the rolling process remains on the surface of the shaped steel, the flame of the torch May ignite rolling oil, etc.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to perform hot sawing more safely and easily in the manufacturing process of a shaped steel having a water cooling step after hot rolling. It is an object of the present invention to provide a structural steel manufacturing facility and a structural steel manufacturing method capable of carrying out the above.

In order to solve the above problems, according to a certain aspect of the present invention, the heated steel is formed while being conveyed by a conveying line, and is provided with a web and a flange provided at least on one end side in the width direction of the web. A section for manufacturing shaped steel that manufactures shaped steel, in which a rolling apparatus that rolls the steel heated to a predetermined temperature into the shape of the shaped steel and the shaped steel rolled by the rolling apparatus are rolled at 600 ° C. A cooling device that water-cools to a temperature below and a part of the shaped steel cooled by the cooling device are guided to a temperature of 600 ° C. or higher with the web surface of the web in the shaped steel facing in the vertical direction. The induction heating device for heating and a sawing machine for sawing the shaped steel in a direction along the width direction of the web so as to include a portion of the shaped steel heated by the induction heating device. The heating device guides a predetermined portion of the web formed in a bar shape extending in the width direction of the web only at a position facing the upper web surface of the upper and lower web surfaces of the web. A structural steel manufacturing facility is provided that has an inductive heating coil for the web that is heated by heating.

Regarding the shaped steel, the term "web height" may be used when describing the dimensions in the direction orthogonal to the length direction of the shaped steel and along the web surface. In the explanation of, for the sake of clarity, it is referred to as "web width".

The length of the shaped steel along the transport direction of the portion heated by the induction heating coil for the web is preferably a length corresponding to the wall thickness of the portion to be heated.

Further, the length of the portion of the shaped steel that is heated by the induction heating coil for the web is preferably in the range of 20 mm to 150 mm along the transport direction.

The separation distance between the induction heating coil for the web and the shaped steel is preferably in the range of 2 mm to 20 mm.

It is preferable that an induction heating coil for a flange that heats a predetermined position of the flange by induction heating is arranged at a position of the flange of the shaped steel facing the surface opposite to the web.

The shaped steel can be an H-shaped steel or a steel sheet pile.

Further, in order to solve the above problems, according to another aspect of the present invention, the heated steel is formed while being conveyed by a conveying line, and is provided on the web and at least one end side in the width direction of the web. A method for manufacturing a shaped steel for producing a shaped steel having a flange, wherein the shaped steel heated to a predetermined temperature is rolled into the shape of the shaped steel, and the shaped steel rolled in the rolling step. A cooling step of water-cooling to a temperature of less than 600 ° C. and a temperature of 600 ° C. or higher in a state where a part of the shaped steel cooled in the cooling step is oriented in the vertical direction with the web surface of the web in the shaped steel Includes an induced heating step of inductive heating and a sawing step of sawing the shaped steel in a direction along the width direction of the web so as to include a portion heated in the induced heating step of the shaped steel. In the induction heating step, the induction for the web formed in a bar shape extending in the width direction of the web is provided only at a position facing the upper web surface of the upper and lower web surfaces of the web. A method for producing a shaped steel is provided in which a predetermined portion of the web is heated by inductive heating by a heating coil.

As described above, according to the present invention, hot sawing can be performed more safely and easily in the manufacturing process of shaped steel having a water cooling step after hot rolling.

It is explanatory drawing which schematically showed the overall structure of the structural steel manufacturing facility which concerns on embodiment of this invention. In the same embodiment, it is sectional drawing which shows typically the arrangement of the induction heating coil for the web of the induction heating apparatus when the shaped steel is H-shaped steel. In the same embodiment, it is a top view which shows typically the arrangement of the induction heating coil for the web of the induction heating apparatus when the shaped steel is H-shaped steel. In the same embodiment, it is sectional drawing which shows typically the arrangement of the induction heating coil for the web of the induction heating apparatus when the shaped steel is a hat type steel sheet pile. It is a schematic cross-sectional view which shows the arrangement of the induction heating coil for a web, and the induction heating coil for a flange in the case where an induction heating device is provided with an induction heating coil for a flange. The case where the shaped steel is H-shaped steel is shown. It is a schematic plan view which shows the arrangement of the induction heating coil for a web and the induction heating coil for a flange when the induction heating apparatus includes an induction heating coil for a flange. The case where the shaped steel is H-shaped steel is shown.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(About the overall configuration of the structural steel manufacturing equipment)
First, with reference to FIG. 1, the overall configuration of the shaped steel manufacturing facility (hereinafter, also simply referred to as “manufacturing facility”) 10 according to the present embodiment will be described in detail. FIG. 1 is an explanatory diagram schematically showing the overall configuration of the shaped steel manufacturing facility according to the present embodiment.

As schematically shown in FIG. 1, the manufacturing equipment 10 according to the present embodiment mainly includes a rolling apparatus 15, a cooling apparatus 17, an induction heating apparatus 19, and a sawing machine 21. These facilities are connected by a transport line 13. Further, in the manufacturing equipment 10 of the present embodiment, the heating furnace 11 is provided on the inlet side (upstream side in the transport direction) of the rolling mill 15 and on the outlet side (downstream side in the transport direction) of the saw cutting machine 21. Is provided with a cooling floor 23.

The shaped steel manufactured by the manufacturing facility 10 according to the present embodiment as shown in FIG. 1 is a shaped steel having a web and a flange provided at least on one end side in the width direction of the web, and is an H-shaped steel. , I-shaped steel, shaped steel with a U-shaped cross section, and shaped steel with flanges at both ends in the width direction of the web, such as hat-shaped steel sheet piles, and Z-shaped steel sheet piles. Such as, Z-shaped shaped steel, T-shaped steel, L-shaped cross section, and other shaped steel with a flange provided only at one end in the width direction of the web are also included. And.

<About steel used>
Prior to explaining each facility of the manufacturing facility 10 according to the present embodiment shown in FIG. 1, first, the steel used in the manufacturing facility 10 according to the present embodiment will be described.
The steel used in the manufacturing facility 10 according to the present embodiment is not particularly limited, and is known as long as it can realize various characteristics (for example, mechanical properties) required for the shaped steel to be manufactured. It is possible to use any steel of.

As such steel, for example, in mass%, C: 0.02% to 0.18%, Mn: 0.3% to 1.8%, Si: 0.60% or less, Al: 0.10% or less, Cu: 1.5% or less, Ni: 3.5% or less, Cr: 2.0% or less, Mo: 1.0% or less, V: 0.20% or less, Nb: 0. Contains one or more of 10% or less, Ti: 0.10% or less, B: 0.0030% or less, P: 0.03% or less, S: 0.03% or less, N: 0. It is limited to 010% or less, O: 0.004% or less, H: 0.001% or less, and the balance may have a chemical composition consisting of Fe and impurities.

Further, as such a steel, more preferably, a steel having a chemical composition as disclosed in Japanese Patent No. 3960341 can be mentioned. In mass%, this steel has C: 0.041% to 0.06%, Si: 0.03% to 0.6%, Mn: 0.3% to 1.6%, P: 0.03%. Hereinafter, S: 0.015% or less, Cu: 0.1% to 0.5%, Ni: 0.1% to 1.5%, Cr: 0.11% to 1.0%, Mo: 0% ~ 0.29%, V: 0.005% ~ 0.10%, Nb: 0.005% ~ 0.07%, Ti: 0.005% ~ 0.03%, B: 0% ~ 0.0005 %, Al: 0.003% to 0.049%, N: 0.008% or less, O: 0.004% or less, H: 0.0001% or less, and the balance is chemical consisting of Fe and impurities. It is a steel having a composition. By having such a chemical composition of steel, it is possible to produce a shaped steel having a strength of 590 MPa class.

Here, the strength of the 590 MPa class means that the mechanical properties of the base material of the shaped steel are that the yield point is 440 MPa to 540 MPa, the tensile strength is 590 MPa to 740 MPa, and the yield ratio is 80% or less. And has an impact characteristic of 47J or more in Charpy absorption energy at 0 ° C. using a V-notch test piece.

<About the heating furnace 11>
A heating furnace 11 for heating the steel used in the manufacturing equipment 10 according to the present embodiment to a predetermined temperature is provided at the uppermost stream of the manufacturing equipment 10 according to the present embodiment. The heating furnace 11 is not particularly limited as long as it can heat the steel to a desired temperature, and a known heating furnace can be used.

The steel used in the manufacturing equipment 10 according to the present embodiment (for example, steel having the above chemical composition) is preferably heated by the heating furnace 11 to, for example, a temperature range of 1000 ° C. to 1350 ° C. .. By setting the heating temperature to 1000 ° C. or higher, the deformation resistance of the steel is lowered, so that the produced shaped steel can be easily rolled. Further, since elements such as Nb and V contained in the steel are solid-solved in the matrix, it is possible to increase the strength of the produced shaped steel after cooling. The lower limit of the heating temperature is more preferably 1100 ° C. Further, by setting the heating temperature to 1350 ° C. or lower, it is possible to prevent coarsening of crystal grains, so that it is possible to realize good impact characteristics in the produced shaped steel. The upper limit of the heating temperature is more preferably 1300 ° C.

The steel heated by the heating furnace 11 is placed on the transfer device constituting the transfer line 13 and transferred to the rolling device 15. The transport device used in the transport line 13 provided in the manufacturing facility 10 according to the present embodiment is not particularly limited, and for example, a transport roller or the like can be used, but the temperature is as described above. Any steel can be used as long as it can convey the steel to be used and the shaped steel having a desired shape.

<About rolling device 15>
On the outlet side of the heating furnace 11, a rolling apparatus 15 is provided for rolling steel heated to a predetermined temperature until it becomes a shaped steel having a desired shape. The rolling apparatus 15 is composed of a plurality of known rolling mills such as a breakdown rolling mill, a universal rolling mill, an edging rolling mill, and the like. In such a rolling apparatus 15, for example, breakdown rolling using a breakdown rolling mill, intermediate rolling using a coarse universal rolling mill and an edging rolling mill, and finishing universal rolling on steel heated to a predetermined temperature. By sequentially performing finish rolling using a machine, the steel changes into a shaped steel having a desired shape (for example, H-shaped steel or steel sheet pile). The configuration of the rolling apparatus 15 is not particularly limited, and a rolling apparatus other than the above configuration may be used.

For example, in the rolling process using the rolling apparatus 15 as described above, the rolling end temperature may be appropriately determined according to the chemical composition of the steel to be used and the desired mechanical properties. For example, when rolling steel having the above chemical composition, the rolling end temperature is preferably in the temperature range of 1000 ° C to 700 ° C. In the shaped steel to be manufactured, the rolling end temperature is preferably 1000 ° C. or lower, more preferably 950 ° C. or lower, in order to secure the impact characteristics. On the other hand, when the rolling end temperature is lower than 700 ° C., the deformation resistance becomes high and the load on the rolling apparatus becomes large. In the produced shaped steel, the cooling start temperature described later is more preferably 750 ° C. or higher in order to secure the tensile strength characteristics, and therefore the rolling end temperature is more preferably 750 ° C. or higher.

The shaped steel formed into a desired shape such as H-shaped steel or steel sheet pile by the rolling apparatus 15 is transferred to the cooling device 17 arranged on the downstream side in the conveying direction of the shaped steel 1 by the conveying line 13. Is transported.

<About cooling device 17>
The shaped steel manufacturing facility 10 according to the present embodiment is intended for a structural steel manufacturing line using TMCP, which enhances the strength of the shaped steel by forming hard structures such as bainite and martensite, making the structure finer, and increasing the dislocation density. It is said. Therefore, on the downstream side of the rolling apparatus 15 in the conveying direction of the shaped steel 1, a cooling device 17 for water-cooling the conveyed shaped steel until the temperature becomes less than 600 ° C. is provided. As such a cooling device 17, it is possible to use a known cooling device capable of performing accelerated cooling, such as a water cooling device having a full cross section.

In the manufacturing equipment 10 according to the present embodiment, after the rolling in the rolling apparatus 15 is completed, the shaped steel is cooled by the cooling apparatus 17 as it is. Therefore, the cooling start temperature is about the same as the rolling end temperature in the rolling apparatus 15. When the cooling start temperature is significantly lower than the rolling end temperature in the rolling apparatus 15, productivity may decrease or it may be difficult to secure desired tensile strength characteristics in the produced shaped steel. There is sex. That is, for example, when accelerating cooling a steel sheet having the above chemical composition, the cooling start temperature is preferably in the temperature range of 1000 ° C to 700 ° C, and is preferably in the temperature range of 950 ° C to 750 ° C. Is more preferable.

Further, in the cooling device 17 according to the present embodiment, the cooling end temperature is set to less than 600 ° C. When the cooling end temperature is 600 ° C. or higher, it is possible to saw as it is without heating, which is outside the scope of this embodiment. Further, when the cooling end temperature is 600 ° C. or higher, it may be difficult to secure the desired tensile strength characteristics in the produced shaped steel, which is not preferable. The lower limit of the cooling end temperature is not particularly specified, but is preferably 300 ° C. or higher. When the cooling end temperature is lower than 300 ° C., it may be difficult to secure the desired impact characteristics in the produced shaped steel.

Further, when cooling a shaped steel formed from steel having the above chemical composition, the cooling end temperature is more preferably 550 ° C. or lower and 300 ° C. or higher. By setting the cooling end temperature to 550 ° C. or lower and 300 ° C. or higher, it is possible to achieve both improvement of mechanical properties by accelerated cooling and reduction of alloy cost. For example, a yield strength of 440 MPa or more, a tensile strength of 590 MPa or more, an excellent tensile strength characteristic of a yield ratio of 80% or less, and a Charpy absorption energy at 0 ° C. using a V-notch test piece are 47 J or more. Excellent impact characteristics are stably secured. The cooling rate in the cooling device 17 according to the present embodiment is not particularly specified, but for example, the average cooling rate from the cooling start temperature to the cooling end temperature in order to obtain excellent tensile characteristics and impact characteristics. Is preferably 0.5 ° C./sec to 50 ° C./sec, and more preferably 0.5 ° C./sec to 15 ° C./sec.

In the present embodiment, the cooling device 17 is configured to cool the shaped steel 1 while traveling straight from the upstream to the downstream in the transport direction of the shaped steel 1, but the shape of the object to be cooled in the cooling device. The steel may be moved back and forth between the upstream side and the downstream side in the transport direction a plurality of times, and finally transported to the induction heating device 19. Further, the cooling device may be arranged on the upstream side of the rolling device, and the shaped steel after rolling may be conveyed and cooled so as to return to the upstream side in the conveying direction.

<About the induction heating device 19>
An induction heating device 19 is provided on the downstream side of the cooling device 17 in the transport direction of the shaped steel 1. The detailed position of the induction heating device 19 in the transport direction of the shaped steel is not particularly limited, but the induction heating treatment of the shaped steel immediately after the completion of cooling should be started in as short a time as possible. Is preferably provided at a position where Here, the induction heating device 19 is in a state where the web surface of the web 3 faces in the vertical direction (in the present embodiment, the substantially vertical direction) with respect to the shaped steel on the transport device constituting the transport line 13. A part of the shaped steel is induced to be heated until the temperature reaches 600 ° C. or higher.
The details of the induction heating device 19 of the present embodiment will be described again below.

<About saw cutting machine 21>
The shaped steel partially heated to 600 ° C. or higher by the induction heating device 19 is sawed by the sawing machine 21 in the direction along the width direction of the web 3 so as to include the heated portion. , A shaped steel having a desired total length. The sawing machine 21 is not particularly limited, and a known sawing machine can be used.

For example, while rotating a circular saw blade, the entire saw blade is moved substantially horizontally from the initial position in a direction along the width direction of the web 3 (in this case, a direction orthogonal to the transport direction) to determine the shape steel. It is possible to use a known sawing machine such as a hot sawing machine that cuts the shaped steel in the width direction. The shaped steel cut by the sawing machine 21 and having a desired total length is conveyed to the cooling floor 23 by the conveying line 13 and is sufficiently cooled.

Here, in the sawing of the shaped steel 1 by the sawing machine 21, the state when the shaped steel 1 is heated by the induction heating device 19, that is, the web surface of the web in the shaped steel 1 is in the vertical direction (the present embodiment). In the case, it is carried out in a state of facing substantially the vertical direction).

(Details of induction heating device 19)
Subsequently, the induction heating device 19 used in the manufacturing facility 10 according to the present embodiment will be described in detail with reference to FIGS. 2A to 3B.

The induction heating device 19 according to the present embodiment raises the temperature of a part of the shaped steel after cooling (specifically, the portion sawn by the saw cutting machine 21) to 600 ° C. or higher, preferably 650 ° C. or higher. Provided for heating. The induction heating device 19 includes an induction heating coil arranged to heat the sawn portion, and an energizing facility (for example, a high frequency power supply and a power cable) for applying a predetermined voltage to the induction heating coil. , At least have. In the induction heating device 19 according to the present embodiment, by adopting a heating method by induction heating instead of a heating means using a flame such as a torch, rolling oil or the like that may remain on the surface of the shaped steel or the like. It is possible to prevent the ignition of the oil content and carry out the operation more safely.

Here, as shown in FIGS. 2A to 2C, the induction heating device 19 is in a direction along the width direction of the web 3 of the shaped steel 1 (in the case of the present embodiment, a substantially horizontal direction orthogonal to the conveying direction of the shaped steel). It has an induction heating coil 101 for a web, which heats a predetermined portion of the web 3 formed in a bar shape extending to the web by induction heating. The induction heating coil 101 for the web is arranged only at a position facing the upper web surface 3a of the upper and lower web surfaces 3a and 3b of the web 3.

As described above, the induction heating device 19 heats a part of the shaped steel 1 on the transport device constituting the transport line 13 in a state where the web surface of the web 3 faces in the vertical direction, so that the induction for the web The heating coil 101 induces and heats the web 3 from the upper web surface 3a side.

At this time, the induction heating coil 101 for the web is formed in a bar shape extending in the width direction of the web 3 of the shaped steel 1, and the web 3 is induced and heated so as to extend in the width direction of the web 3. The sawing machine 21 can suppress the cutting resistance to be small when the shaped steel 1 is sawed in the width direction of the web 3. As a result, the sawing machine 21 can easily saw the portion of the shaped steel 1 heated by the induction heating coil 101 for the web of the induction heating device 19 in the direction along the width direction of the web 3. Therefore, stable and reliable sawing is possible.

Regarding the induction heating coil 101 for the web, for example, the shaped steel 1 to be heated is provided with a pair of flanges 5, 5 at both ends in the width direction of the web 3, as shown in FIGS. 2A and 2B. In the case of shaped steel, the induction heating coil 101 for the web is arranged between the pair of flanges 5, 5 at a position facing the web surface 3a on the upper side of the web 3. Then, the web 3 is induced and heated from the upper web surface 3a side by the induction heating coil 101 for the web.

Further, as shown in FIG. 2C, the shaped steel 1 to be heated is a steel sheet pile provided with a pair of flanges 5 and 5 inclined at both ends in the width direction of the web 3 (more specifically, a so-called hat-shaped steel sheet pile). ) Is the same. That is, when the pair of flanges 5 and 5 of the shaped steel 1 are heated by the induction heating device 19 in a state of rising upward (actually, diagonally upward) from the web 3, the induction heating coil 101 for the web Is arranged between a pair of flanges 5 and 5 at positions facing the upper web surface 3a of the web 3, and the web 3 is induced and heated from the upper web surface 3a by the induction heating coil 101 for the web. To. When the shaped steel is a hat-shaped steel sheet pile, it is heated by the induction heating device 19 in a state where the pair of flanges extend downward (that is, the shaped steel is turned upside down as shown in FIG. 2C). In this case, the induction heating coil 101 for the web is not located between the pair of flanges. However, even in this case, the induction heating coil for the web is still arranged only at the position facing the web surface 3a on the upper side of the web 3, and the web 3 is upward by the induction heating coil 101 for the web. Induction heating is performed from the side web surface 3a.

Even if the shaped steel has a flange provided only at one end in the width direction of the web, the induction heating device heats a part of the shaped steel with the web surface of the web facing in the vertical direction. , The induction heating coil for the web is arranged only at a position facing the web surface on the upper side of the web. Then, the web is induced and heated from the upper web surface by the induction heating coil for the web.

On the other hand, as shown in FIGS. 2A and 2B, the induction heating device 19 has no heating member including an induction heating coil for the web on the lower web surface 3b side of the web 3 of the shaped steel 1. Not.

Since a transport device such as a transport roll constituting a transport line is provided below the web 3 of the shaped steel 1, if an induction heating coil for the web is arranged on this side, the induction for the web is induced. The heating coil, the energizing equipment (not shown), and the transfer device interfere with each other, making it difficult to achieve both transfer and heating.

Further, in the manufacturing process of the shaped steel 1 by TMCP as shown in FIG. 1, accelerated cooling by water cooling or the like is performed by the cooling device 17 before the induction heating device 19, but after cooling by the cooling device 17, the cooling material is used. It is considered that the water is left on the upper surface of the web 3 in the vertical direction. At this time, when the shaped steel 1 after accelerated cooling is conveyed to the induction heating device 19 or its vicinity, the web surface 3a on the upper side of the web 3 functions like a rain gutter, and the web surface 3a on the upper side functions like a rain gutter. It is expected that the water remaining on 3a will flow down. At this time, if the energizing equipment is arranged on the side of the web 3 facing the conveying surface of the conveying line, the water that has flowed down will be applied to the energizing equipment, and there is a concern that electric leakage or the like may occur. Become. Further, even if a member other than the induction heating coil, such as a torch, is used as the heating member for heating the web of the shaped steel, the cooling water may be applied to the heating member, and the heating efficiency is lowered. Alternatively, uneven heating of the shaped steel may be impaired in stable heating of the shaped steel, which may adversely affect the sawing of the shaped steel.

Therefore, the induction heating device is provided with an induction heating coil for the web only at a position facing the upper web surface of the upper and lower web surfaces on the web, and an induction heating coil for the web is provided on the lower web surface side. No heating member including the coil is provided. As a result, it is possible to stably achieve both transportation and heating while ensuring safety, and it is possible to more easily perform hot sawing even in the online process as shown in FIG.

From this point of view, the induction heating device 19 according to the present embodiment is safer by not disposing the induction heating coil 101 below the web 3, that is, on the side facing the transfer surface of the transfer line. It made it possible to carry out hot sawing.

Here, when the web of the shaped steel is heated by the induction heating by the induction heating coil for the web, the separation distance between the induction heating coil for the web and the web surface on the upper side of the web (FIGS. 2A and 2C, Further, the distance d) between the web surface 3a on the upper side of the web 3 and the induction heating coil 101 for the web in FIG. 3A, which will be described later, is preferably in the range of 2 mm to 20 mm.

If the separation distance between the induction heating coil for the web and the web surface on the upper side of the web is less than 2 mm, there is a high possibility that the induction heating coil for the web and the web of the shaped steel will come into contact with each other. Therefore, it is not preferable, on the other hand, when the separation distance is more than 20 mm, the heating efficiency of the web of the shaped steel by the induction heating coil for the web is lowered, which is not preferable. By setting the separation distance between the induction heating coil for the web and the web surface on the upper side of the web in the range of 2 mm to 20 mm, contact between the induction heating coil for the web and the web of the shaped steel is prevented. It is possible to heat the shaped steel efficiently. In addition, in order to further reduce the possibility that the induction heating coil for the web and the web of the shaped steel come into contact with each other and to improve the heating efficiency of the web of the shaped steel by the induction heating coil for the web, the induction heating for the web is performed. The separation distance between the coil and the web surface on the upper side of the web is more preferably in the range of 5 mm to 10 mm.

A plurality of types of induction heating coils 101 for the web are prepared according to the width of the web 3 of the shaped steel 1 manufactured by the manufacturing facility 10, and are appropriately selected according to the web 3 of the shaped steel 1 manufactured. It is preferable to be done.

Further, regarding the size of the induction heating coil 101 for the web in the length direction, it is preferable that the shape steel 1 can be heated over almost the entire width of the web 3. Since the shaped steel 1 is heated to the web 3 while the shaped steel 1 is being conveyed on the conveying line, the induction heating coil 101 for the web is heated at the time of the induction heating of the web 3. It is important that the size in the length direction is such that it does not come into contact with the flange 5 of the target shaped steel 1.

Further, when the web 3 of the shaped steel 1 is heated by the induction heating coil 101 for the web, the length of the portion of the web 3 heated by the induction heating coil 101 for the web in the direction along the transport direction is the portion to be heated. It is preferable that the length corresponds to the wall thickness of.

This point will be described in detail. FIG. 2B is a schematic view of the case where the shaped steel 1 and the induction heating coil 101 for the web are viewed from above (plan view), taking the case where the shaped steel 1 is an H-shaped steel as an example. The present inventors have focused on the length L along the transport direction of the portion heated by the induction heating coil 101 for the web in the web 3 of the shaped steel 1 as shown in FIG. 2B, and are known to be finite. A thermal conduction analysis simulation using the element method was carried out. Specifically, a steel sheet in a state of 550 ° C. was heated from one side by induction heating, and the state until the temperature on the other side reached 650 ° C. was analyzed using a known analysis application. A detailed analysis of the obtained results revealed that the heat generated by the induction heating spreads in a circle with a spread close to the plate thickness and is conducted to the back side of the steel plate.

From such a simulation result, by setting the length L of the heated portion as shown in FIG. 2B to about the length corresponding to the wall thickness of the heated portion, the back side of the web 3 (in this case, the lower side) is set. It was found that the web surface 3b on the lower side of the web 3 can be sufficiently heated without installing the induction heating coil 101 for the web on the web surface 3b side). Therefore, it is preferable that the length L of the heated portion as shown in FIG. 2B is the wall thickness of the heated portion, that is, the length corresponding to the thickness of the web 3 in this case.

More specifically, the length in the direction along the transport direction of the part of the web to be heated by the induction heating coil for the web (the length of the part to be heated (L)) is the wall thickness of the part to be heated (the thickness of the web). Assuming that the length is 10 mm to 125 mm, it is preferably in the range of 20 mm to 150 mm. If the length of the part to be heated is less than 20 mm, the length of the part to be heated becomes too narrow, and in the sawing process by the sawing machine, the positioning accuracy of the sawing machine is insufficient and hot sawing is performed. It is not preferable because it may reduce the property (that is, saw the part that is not sufficiently heated). On the other hand, when the length of the portion to be heated exceeds 150 mm, the length of the heated portion becomes too wide, which may take a lot of time for heating, which is not preferable. By setting the length of the portion to be heated in the range of 20 mm to 150 mm, it is possible to perform heating without requiring a large heating time while maintaining hot sawability.

By the way, as shown in FIGS. 3A and 3B, in the induction heating device 19 according to the present embodiment, the surface of the flange 5 formed on the shaped steel 1 on the opposite side to the web 3 (so-called outer side of the flange 5). The induction heating coil 102 for the flange can be arranged separately from the induction heating coil 101 for the web at a position facing the surface of the web. The induction heating coil 102 for the flange is located at a position corresponding to the induction heating coil 101 for the web, that is, a position corresponding to a portion of the flange 5 of the shaped steel 1 to be heated by the induction heating coil 101 for the web. Is arranged at a position where it can be heated. Then, it is possible to heat the heating target portion of the facing flange 5 to a temperature of 600 ° C. or higher.

As a result, since the induction heating coil 102 for the flange can heat the predetermined position of the flange 5 of the shaped steel 1, that is, the position to be sawn by the saw cutting machine 21, the shaped steel by the saw cutting machine 21. The cutting resistance of the flange 5 at the time of sawing 1 can be suppressed as small as possible, the shaped steel 1 can be sawed more stably, and the consumption of the saw blade and the like of the saw cutting machine 21 can be suppressed as much as possible. It becomes possible.

As for the configuration of the induction heating coil 102 for the flange, basically the same configuration as that of the induction heating coil 101 for the web can be used. Further, it is preferable that the induction heating coil 102 for the flange can perform induction heating over the entire width of the flange 5 to be heated.

On the other hand, the induction heating coil 102 for the flange is not arranged at all on the lower side of the shaped steel 1 including the lower side of the flange 5 (more specifically, in the vertical downward direction of the shaped steel 1). This configuration is for the same reason as the induction heating coil for the web, that is, to prevent interference between the induction heating coil for the flange and the energization equipment and the transfer device, and to prevent the cooling water used for cooling from flowing down and energize. This is to prevent the occurrence of electric leakage due to the equipment, and to achieve both transportation and heating.

Regarding the induction heating coil 102 for the flange, for example, when the shaped steel 1 to be heated is an H-shaped steel having a pair of flanges 5 and 5 at both ends of the web 3, as shown in FIGS. 3A and 3B, each of them. Induction heating coils 102 for bar-shaped flanges extending in the width direction (vertical direction in this case) of the flanges 5 and 5 are arranged at positions facing the surfaces of the flanges 5 and 5 opposite to the web 3. Will be done. Alternatively, in order to heat one of the flanges 5, the induction heating coil 102 for the flange may be provided only at a position facing the surface of the one flange 5 opposite to the web 3. Further, in order to heat the pair of flanges 5, heating is required even when the induction heating coils 102 for the flanges are provided at positions of the flanges 5 facing the surface opposite to the web 3. Only one flange 5 may be selectively induced and heated.

In the case of the present embodiment, the induction heating coils 102 and 102 for the flange have a size in the length direction, and the length in the width direction of the flange 5 of the shaped steel 1 (in the vertical direction in FIG. 3A). It is formed larger than the length) so that induction heating can be stably performed over the entire width of the flange.

Further, when the shaped steel 1 to be heated is a hat-shaped steel sheet pile as shown in FIG. 2C, the pair of flanges 5 are inclined at a constant angle with respect to the web 3 so as to be separated from each other as the distance from the web 3 increases. It is in a state of being. The induction heating coil for the flange in this case is in the direction from the web side (base end side) to the arm portion side (tip side) of each flange (that is, the width of the flange) along the surface of each flange opposite to the web. It has a bar-shaped structure extending in the direction).

Further, in the case of a shaped steel having a flange provided only at one end in the width direction of the web, an induction heating coil for the flange for heating the flange is provided at a position of the flange facing the surface opposite to the web. Just do it.

Here, when the flange of the shaped steel is heated by the induction heating by the induction heating coil for the flange, the separation distance between the induction heating coil for the flange and the flange to be heated by the induction heating coil for the flange. (In FIG. 3B, the distance d'between the flange 5 and the induction heating coil 102 for the flange facing the flange 5) is preferably in the range of 2 mm to 20 mm.

If the separation distance between the induction heating coil for the flange and the flange to be heated is less than 2 mm, there is a high possibility that the induction heating coil for the flange and the flange facing the flange will come into contact with each other. On the other hand, when the separation distance between the induction heating coil for the flange and the flange to be heated is more than 20 mm, the heating efficiency of the flange by the induction heating coil for the flange is lowered, which is not preferable. .. By setting the separation distance between the induction heating coil for the flange and the flange to be heated in the range of 2 mm to 20 mm, the shaped steel is efficiently heated while preventing contact between the induction heating coil for the flange and the flange. It becomes possible to do. In order to further reduce the possibility of contact between the flange induction heating coil and the flange and further increase the flange heating efficiency by the flange induction heating coil, the flange induction heating coil and the flange to be heated are used. The separation distance between them is more preferably in the range of 5 mm to 10 mm.

The distance between the induction heating coil for the web and the web surface on the upper surface side of the web (reference numeral d in FIG. 3A) is as described above regardless of the presence or absence of the induction heating coil for the flange. is there.

Further, when the flange 5 of the shaped steel 1 is heated by the induction heating coil 102 for the flange, the length of the portion of the flange 5 to be heated by the induction heating coil 102 for the flange in the direction along the transport direction is heated. It is preferable that the length corresponds to the wall thickness of the portion, that is, the thickness of the flange 5. Regarding this point, it is preferable that the length of the portion of the web 3 to be heated by the induction heating coil 101 for the web in the direction along the transport direction is a length corresponding to the wall thickness of the portion to be heated. For the same reason.

As a result, the sawing position of the shaped steel 1 flange 5 by the sawing machine 21 can be stably and surely heated with respect to the thickness direction of the flange 5, so that the flange 5 by the sawing machine 21 can be heated stably and surely. It becomes possible to perform sawing of the shape steel 1 more stably.

A plurality of types of induction heating coils 102 for flanges are prepared according to the width of the flange 5 of the shaped steel 1 manufactured by the manufacturing facility 10, and are appropriately selected according to the flange 5 of the shaped steel 1 manufactured. It is preferable to be done. Further, the induction heating coil 102 for the flange preferably has a size suitable for the maximum width of the flange 5 of the shaped steel 1 manufactured by the manufacturing facility 10. By doing so, even when the size of the shaped steel manufactured in the manufacturing facility 10 changes, it is possible to appropriately carry out the induction heating treatment according to the shaped steel to be manufactured.

Hereinafter, a method of manufacturing the shaped steel 1 using the manufacturing facility 10 having the above configuration will be described.

The method for producing shaped steel in the present embodiment includes a rolling step of rolling a heated steel into a web and a shaped steel having a flange provided at least on one end side in the width direction of the web, and a rolled shaped steel. It includes a cooling step of cooling the shape with water, an induced heating step of heating a part of the shaped steel by induced heating, and a sawing step of sawing a heated portion in the induced heating step with a sawing machine.

Specifically, in the rolling step, the steel heated to a predetermined temperature by the heating furnace 11 is rolled into a web and a shaped steel having a desired shape provided with a flange provided at least on one end side in the width direction of the web by the rolling apparatus 15. Roll to.

After the rolling step, a cooling step of cooling the rolled shaped steel with water until the temperature becomes less than 600 ° C. is carried out by the cooling device 17, and the structure or the like is created in order to give the shaped steel a predetermined performance. ..

After the cooling step, an induction heating step is performed in which a part of the cooled section is heated to a temperature of 600 ° C. or higher by the induction heating device 19 with the web surface of the web of the shaped steel facing up and down. carry out.

At this time, in the induction heating step, the induction heating device 19 is provided along the width direction of the web provided only at a position facing the upper web surface 3a of the upper and lower web surfaces of the web 3 of the shaped steel 1. A predetermined portion of the web 3 is heated by induction heating by the induction heating coil 101 for the web formed in a bar shape extending in the direction. As a result, the sawing target portion of the web 3 is induced and heated in the direction along the width direction of the web, that is, in the direction in which the shaped steel 1 is sawed in the sawing step.

Since the induction heating device 19 does not have a heating member for heating the web 3 on the lower side of the web 3 of the shaped steel 1, in the induction heating step, the lower side of the web 3 of the shaped steel 1 is formed. Do not heat from the web surface 3b side.

On the other hand, when the induction heating device 19 includes the induction heating coil 102 for the flange, the induction heating coil 102 for the flange faces the induction heating coil 102 for the flange on the flange 5 of the shaped steel 1. Heat the surface. As a result, in addition to the sawing target portion of the web 3 of the shaped steel 1, the sawing target portion of the flange 5 is also induced and heated, so that when the shaped steel 1 is sawed in the sawing step of the next step, the shape is formed. The increase in the cutting resistance of the steel 1 can be suppressed as much as possible, and more stable sawing and wear of the saw blade of the saw cutting machine 21 can be suppressed as much as possible.

After the induction heating step, the saw cutting step is carried out by the saw cutting machine 21. In this sawing step, sawing is started from a position corresponding to the heated portion of the web 3 heated by the induction heating step. In the sawing step, the shaped steel 1 is sawed in the direction along the width direction of the web 3. At this time, since the sawing target portion of the web 3 of the shaped steel 1 (further flange 5 when heating is performed by the induction heating coil 102 for the flange) is heated to 600 ° C. or higher in the induction heating step. Saw cutting by the saw cutting machine 21 can be easily and stably performed.

In the sawing of the shaped steel 1 by the saw cutting machine 21, for example, the saw blade of the saw cutting machine 21 is conveyed from the initial position of the saw blade in a state where the web surface of the web 3 of the shaped steel 1 faces in the vertical direction. This is done by moving in the direction across the line 13. More specifically, if the shaped steel 1 is an H-shaped steel as shown in FIGS. 2A and 2B, 3A and 3B, or a hat-shaped steel sheet pile as shown in FIG. 2C, it is sawn. By moving the saw blade of the machine 21 from the initial position, the shaped steel 1 is sawn from one flange 5 side toward the other flange. Thereby, the shaped steel 1 can be sawed in the direction along the width direction of the web 3 (that is, the width direction of the shaped steel).

(Summary)
As described above, according to the shaped steel manufacturing equipment and the shaped steel manufacturing method according to the present embodiment, the possibility of electric leakage or ignition in the shaped steel manufacturing process having a water cooling step after hot rolling is suppressed. As a result, hot sawing can be performed more safely and easily.

Further, in the shaped steel manufacturing facility according to the present embodiment, since a part of the shaped steel is heated by using an induction heating coil, it is possible to change the size of the shaped steel and improve the operability. it can.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 Shaped steel 3 Web 3a Upper web surface on the web 5 Flange 10 Shaped steel manufacturing equipment 11 Heating furnace 13 Transfer line 15 Rolling equipment 17 Cooling equipment 19 Induction heating equipment 21 Saw cutter 23 Cooling floor 101 Induction heating for the web Coil 102 Induction heating coil for flange

Claims (7)

A structural steel manufacturing facility that forms a heated steel while transporting it by a transport line to produce a shaped steel having a web and a flange provided at least on one end side in the width direction of the web.
A rolling apparatus that rolls the steel heated to a predetermined temperature into the shape of the shaped steel, and
A cooling device that water-cools the shaped steel rolled by the rolling device to a temperature of less than 600 ° C.
An induction heating device that induces and heats a part of the shaped steel cooled by the cooling device to a temperature of 600 ° C. or higher with the web surface of the web of the shaped steel facing in the vertical direction.
A sawing machine that saws the shaped steel in a direction along the width direction of the web so as to include a portion of the shaped steel that has been heated by the induction heating device.
With
The induction heating device is formed at a predetermined portion of the web, which is formed in a bar shape extending in a direction along the width direction of the web only at a position facing the upper web surface of the upper and lower web surfaces of the web. A shaped steel manufacturing facility that has an induction heating coil for the web, which heats the web by induction heating. The shaped steel according to claim 1, wherein the length of the shaped steel along the transport direction of the portion heated by the induction heating coil for the web is a length corresponding to the wall thickness of the heated portion. production equipment. The structural steel manufacturing facility according to claim 1 or 2, wherein the length of the portion of the shaped steel heated by the induction heating coil for the web along the transport direction is in the range of 20 mm to 150 mm. The structural steel manufacturing facility according to any one of claims 1 to 3, wherein the separation distance between the induction heating coil for the web and the shaped steel is in the range of 2 mm to 20 mm. Claims 1 to 4, wherein an induction heating coil for a flange that heats a predetermined position of the flange by induction heating is arranged at a position of the flange of the shaped steel facing the surface opposite to the web. The shaped steel manufacturing facility according to any one of the items. The structural steel manufacturing facility according to any one of claims 1 to 5, wherein the shaped steel is an H-shaped steel or a steel sheet pile. A method for producing a shaped steel, wherein the heated steel is formed while being conveyed by a conveying line to produce a shaped steel having a web and a flange provided at least on one end side in the width direction of the web.
A rolling process of rolling the steel heated to a predetermined temperature into the shape of the shaped steel,
A cooling step of water-cooling the shaped steel rolled in the rolling step to a temperature of less than 600 ° C.
An induction heating step of inducing heating a part of the shaped steel cooled in the cooling step to a temperature of 600 ° C. or higher with the web surface of the web of the shaped steel facing up and down.
A sawing step of sawing the shaped steel in a direction along the width direction of the web so as to include a portion heated in the induction heating step of the shaped steel.
Including
In the induction heating step, induction heating for a web formed in a bar shape extending in the width direction of the web is provided only at a position facing the upper web surface of the upper and lower web surfaces of the web. A method for producing a shaped steel, in which a predetermined portion of the web is heated by induction heating with a coil.

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