WO2009154299A1

WO2009154299A1 - Steel t-bar

Info

Publication number: WO2009154299A1
Application number: PCT/JP2009/061437
Authority: WO
Inventors: 竹正峰康; 堀田知夫; 高嶋由紀雄; 高橋英樹; 山口陽一郎
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2008-06-18
Filing date: 2009-06-17
Publication date: 2009-12-23
Also published as: KR20100131016A; JP4420130B2; KR101022718B1; TW201004723A; TWI364330B; CN102066014A; CN102066014B; JP2010023114A

Abstract

Provided is a steel T-bar having a web height of at least 150 mm and having no welds. The cross-sectional shape, in the bar width direction, of a fillet section formed at the joint between the web and the flange is an arc that contacts the web and the flange. The radius of the arc is between 2 and 10 mm, and the shape and size of the fillet section are optimized. This configuration allows substantial improvement in work efficiency when welding ends together, when the T-bars are used as T-longitudinals in shipbuilding.

Description

Description Title of invention: T-section steel Technical field

[0001]

The present invention relates to a T-bar used in the fields of shipbuilding, bridges, construction, and the like. The T-shaped steel of the present invention is particularly suitable as a shipbuilding material, and particularly suitable for use as a T-longitudinal material. Background art

[0002]

In order to improve the cross-sectional performance and reduce the weight of the steel used by increasing the size of the hull, the force S, which used to be a spherical plate (bulb plate), was used as a reinforcing steel for the hull structure in the past. scalene unequal thickness angle steel having a cross-sectional shape shown in (NAB: unequal leg and thickness angle ) is _c, however it has many summer and used, scalene unequal thickness angle steel is the asymmetry of the cross section Therefore, when reinforcing the hull, it has directionality in the cross-sectional performance, and when it receives a force such as water pressure from the outside of the hull, a torsional force (torsional stress) is generated in the cross section. For this reason, in order to satisfy the structural performance requirements, it is necessary to use a section steel with a cross-sectional performance that can withstand the torsional force described above. May result in a demerit that increases.

[0003]

In addition, crude oil tankers that are newly built in recent years are subject to (a) a double hull type (double hull type) Etc.) (b) Mid-deck type (crude oil tank is divided into two layers, upper and lower, and only the ship side has a double structure. At the same time, by placing an intermediary deck that separates the upper and lower tanks below the water line, the crude oil pressure in the lower tank is always kept lower than the surrounding water pressure. Even if it is opened, it is obliged to adopt one of the following, which is pushed up by the pressure of the seawater into which the crude oil in the lower tank enters and trapped in the tank). In particular, the double hull is used as a ballast water tank that allows stable vessel navigation by injecting seawater when there is no cargo. For this reason, the long materials placed on the bottom of the ship and the ship wall are directly immersed in seawater, so anti-corrosion coating is applied to ensure sufficient corrosion resistance. Therefore, it is required to ensure the adhesion of the coating film.

[0004]

In recent years, a T-longi material with a T-shaped cross-sectional shape (cross-sectional shape in the width direction of the steel shape) as shown in Fig. 10 and a cross-sectional shape that is axisymmetric about the web is used as a hull-capturing member. It has come to be used. As this T longi material, a thick plate cut and welded assembly is widely used, and such a T longi material (hereinafter sometimes referred to as “welded T_bar”) is a web. There is a weld at the joint between the web and flange. However, when this weld is painted, the weld bead has a concave shape, resulting in non-uniform coating thickness and as-weld surface concave portions and edge portions. This will cause selective corrosion and a serious problem of corrosion deterioration of the hull structural members. In order to prevent the formation of such an imperfection coating film, the welded longe material is repaired with a grinder or the like so that the surface of the weld bead becomes smooth, and then painted. Is called. This kind of repair of the weld bead before painting is time-consuming because it requires manual inspection with the grinder etc. after inspecting the part that needs to be repaired over the entire length of the shape steel. And increased costs due to increased labor costs.

[0005]

On the other hand, the shape steel obtained by hot rolling is used for such a welded T-longage material, and in the case of this T-longage material, Since there is no proper welding assembly, there is no problem with painting the weld as described above. Patent Document 1 describes a T-shaped steel (hereinafter referred to as “cut T-bar”) that is manufactured by forming a H-shaped steel by hot rolling and then cutting the web part in half (divided into two parts). Is used as T-longi material. In Patent Documents 2 and 3, T-steel obtained directly by hot rolling (hereinafter sometimes referred to as “rolled T-bar”) is used as T-longier material. It is shown. Prior art documents

Patent Literature

Patent Document 1: JP 2002-301501 A

Patent Document 2: Japanese Patent Laid-Open No. 11-342401

Patent Document 3: Japanese Patent Laid-Open No. 2007-331027 Summary of the Invention

Problems to be solved by the invention [0006]

However, there are the following problems with T-longages made of the above-mentioned conventional cut T-section steel and rolled T-section steel.

[0007]

ΤLongji is often used as a longitudinal along the length of the hull. In this case, multiple T-longages (T-shaped steel) with a length of about 10 to 20m are welded and joined in the longitudinal direction to obtain a long hull structural material (reinforcing material). The welded part between such T-longages is the hull structural material! / Due to the nature, all must have the proper strength. However, when conventional cut T-section steel or rolled T-section steel is used, there is a possibility that a crack will occur at the welded joint between T-longi materials and that the strength of the joint may be reduced. is there. In order to prevent this, preparatory work that would significantly reduce the work efficiency of welding work has been required.

[0008]

However, as a result of investigations by the present inventors, it has been found that if the shape of the rolled T-section steel is optimized, the burden of the preliminary work is greatly improved.

[0009]

Therefore, the object of the present invention is to solve such problems of the prior art and to be applied to structural materials etc. in the fields of shipbuilding, bridges, construction, etc., especially for τ longi materials for hull structures. In such a case, the object is to provide a T-shaped steel with excellent workability for welding joints between the longines. Means for solving the problem

[0010]

The inventors of the present invention have studied the problems that occur in welding joining of T-longi materials and their countermeasures when the conventional cut T-shaped steel and rolled T-shaped steel are applied to T longi materials. The following knowledge was obtained.

[0011]

When the ends of T-longi materials are welded together, welding is performed after the butt portion is grooved. At this time, the scallop process is performed to cut out the web P- part in contact with the flange into a fan shape in order to avoid material deterioration and weld defects due to the intersection of the weld line between the flange and the web.

[0012]

Fig. 11 shows an example of groove processing of the joint of T-longi material (T-section steel). The left side of the figure is T-longi material W

Four

The right side is a front view of the end of the T-longi material, and the part surrounded by the broken line is the scalloped part. As shown in the figure, each of the flange and web butt portions is grooved. Here, cut T-section steel and rolled T-section steel have a fillet section (arc section indicated by fi in Fig. 11 and Fig. 1 described later) at the joint between the web and flange. In the above-described force lapping process, it is necessary to remove the fillet portion so that the inner surface of the flange becomes flat. When the processed surface with the fillet removed is insufficiently rough and has a rough processed surface, cracks occur in the weld joint due to the problems described above, i.e., stress concentration and strain concentration. As a result, there is a possibility that the strength of the joint is lowered.

[0013]

Conventional cut T-section steel and rolled T-section steel used for T-longages have a circular arc shape with a radius of about 13 mm (generally referred to as fillet R) for the reasons described below. It has the above fillet part.

[0014]

First, cut T-section steel is manufactured by cutting the H-section steel (rolled H-section steel) obtained by hot rolling in half (divided into two parts). Have. The size of fillet R in the fillet part of rolled H-section steel is standardized by the Japanese Industrial Standard (JIS). Fillet R increases as the size of H-section steel increases. In general, T-longages for hull structures often have a web height of 150 mm or more and a web height of more than twice the flange width. According to the Japanese Industrial Standard (JIS), the fillet R of a rolled H-section steel with a web height of 300 mm is 13 mm. Therefore, the cut T-section steel for a T-longier material with a web height of 150 mm or more is obtained. The fillet R is 13mm or more.

[0015]

On the other hand, there is no standardized bullet R dimension of rolled T-section steel like rolled H-section steel, but the conventional manufacturing method of rolled T-section is equivalent to that of rolled H-section steel. It must be large. For example, in the method of producing a rolled T-section steel disclosed in Patent Document 3, hot rolling of the T-section steel is performed using a coarse universal mill and a finishing universal mill. In this hot rolling, the portion of the T-shaped steel to be a buillet is rolled at the roll corner (flange-side roll corner) of the horizontal roll of the coarse universal rolling mill, and then finished universal rolling. Formed at the roll corner (flange-side roll corner) of the horizontal roll of the machine and built into a circular arc shape. The horizontal roll corner R (radius) of these coarse universal rolling mills and finishing universal rolling mills is often the same size, but the roll corner R should be made very small for the following reasons. I can't. [0016]

(a) When roll corner R is reduced, the contact condition between the roll corner and the inner surface of the flange becomes severe, and scoring occurs between the two. For this reason, seizure flaws occur on the inner surface of the flange, making it impossible to produce a product of the proper quality.

(b) Roll wear at the roll corner increases, roll corner R increases as rolling continues, and the arc shape collapses, making it impossible to form a smooth single-radius arc. For this reason, it is necessary to frequently perform roll exchange, which reduces productivity and increases manufacturing costs. In other words, it becomes difficult to mass-produce products at low cost.

(c) Roll corner The temperature of the roll corner becomes easier to rise as R is smaller, so the roll material deteriorates or is damaged by heat. If cracks or chipping occurs at the roll corner, the roll must be replaced, and productivity is reduced.

[0017]

The problems as described above are particularly remarkable in a rough universal rolling mill having a large number of rolling operations and a high rolling reduction. For this reason, the roll corner R of the horizontal roll is configured to have a sufficiently large dimension so as not to cause the above problems (a) to (c), and as a result, the dimension of the fillet R of the rolled T-shaped steel to be manufactured. Is also the corresponding size.

[0018]

Further, in the method for producing a rolled T-section steel of Patent Document 2, hot rolling of the T-section steel is performed using a two-roll type mill equipped with upper and lower rolls. In this hot rolling, the portion that should become the fillet part of the T-shaped steel is rolled at a specific part of the upper and lower rolls constituting the hole mold. In the upper roll where the inner surface has an angle close to vertical, seizure occurs between the arc tip of the roll part and the inner surface of the flange. For this reason, seizure flaws occur on the inner surface of the flange, making it impossible to produce a product shape steel of appropriate quality. For this reason, the arc radius of the roll part where the fillet part is to be rolled is configured to have a sufficiently large dimension so as not to cause the above-mentioned problems. It becomes the size to do. The shape steel of Patent Document 2 has a T-shaped cross section, but the cross-sectional shape has a taper that is thinner at the tip of the flange. It is not possible to produce uniform T-shaped steel.

[0019]

In the scalloping process described above, the larger the fillet R (fillet R is indicated by rl in FIG. 11), the larger the volume and width of the fillet part. The width of the power part will increase. In other words, with a large fillet R such as a conventional cut T-shaped steel or rolled T-shaped steel, the scalloped finishing area is large, and it is easy to produce a portion where the finishing accuracy is not sufficient. It has been found that this causes the problem of reduced work efficiency.

[0020]

Specifically, when the web and fillet are removed by scalloping, for example, by gas cutting, the gas cut surface is generally finished by manual grinder finishing. Therefore, the larger the finished area, the longer it takes to remove the gas notch, which tends to have variations in finishing accuracy, and the efficiency of the welding work is greatly reduced. Also, in the case of machining with a grinding machine, since the area of the finishing process is large, the wear of the grinding tip increases, and the machining efficiency decreases as the replacement frequency increases. However, if there is a part with insufficient finishing accuracy, cracks will occur due to stress concentration or strain concentration after welding joining and the strength of the welded joint will be reduced, resulting in poor welding work efficiency. However, the machined surface must be finished with high accuracy.

[0021]

Based on the above findings, the optimum shape-size of the T-section steel fillet used as T-longi material was examined. As a result, the fillet R of the fillet with an arc-shaped cross section was 10 mm or less, preferably 8 m. It was concluded that by setting it to m or less, the work efficiency of scallop processing is greatly improved without causing a decrease in the strength of the welded joint due to poor finish of scallop processing. In addition, the force required to bend the T longi material along the hull. When the fillet R is small, the cross-section of the fillet becomes smaller, which improves the bending workability. It was found that the work efficiency during bending can be improved.

[0022]

The present invention has been made on the basis of such findings and has the following gist.

(1) T-shaped steel with a web height of 150 mm or more and no welded portion, and the cross-sectional shape in the cross-section direction of the billet formed at the joint between the web and the flange is T-section steel, characterized in that it is arcuate in contact with the flange and the radius r1 of the arc is 2 to: LOmm.

(2) The T-section steel according to (1), wherein the height of the web is at least twice the width of the flange.

(3) The T-section steel according to (1) or (2) above, which is processed into a T-section steel by hot rolling.

In particular, it is preferable to heat the raw steel slab using a universal rolling mill and process it into a T-shaped steel. Good.

(4) Above the above (1) to ( ³ ) above, either of the T-shape steels! / ずれ, the half-diameter force of the arc of the fillet on both sides of the web must be constant over the entire length of the shape steel. T-shaped steel characterized by

(5) In the T-section steel of any of the above (1) to (4), the cross-sectional shape in the shape steel width direction of the corner portion at the flange tip is an arc shape, and the radial force of the arc is not less than mm. T-shaped steel characterized by

(6) T-shaped steel as defined in any one of the above (ii) to (5), which is a T-shaped steel for ship structure

The invention's effect

[0023]

The T-shaped steel of the present invention has an optimized shape and size of the fillet formed at the joint between the tube and the flange, and has a smaller fillet R than the conventional T-shaped steel. According to the present invention, the work efficiency of scalloping is greatly improved without causing a decrease in the strength of the welded joint due to poor finish of the scalloping performed when the ends are welded together as a T longi material. When the longi material is bent along the hull, the bending workability is also improved. For this reason, it is particularly suitable as a T-section steel for hull structures, especially as a T-longi material. Brief Description of Drawings

[0024]

FIG. 1 is an explanatory view showing an example of a cross-sectional shape of a T-section steel of the present invention.

[Fig. ² ] Fig. 2 compares the relationship between the modulus of section with welded plate and the unit weight of the T-shaped steel of the present invention shown in Table 2 with the conventional unequal non-uniform thickness steel. It is a graph shown.

FIG. 3 is an explanatory view showing an example of rolling equipment for producing the T-section steel of the present invention.

FIG. 4 is a front view schematically showing the roll configuration of the first rough universal rolling mill in the rolling equipment of FIG. 3.

FIG. 5 is a front view schematically showing a roll configuration of an edger rolling mill (edger mill) in the rolling equipment of FIG. 3. -

FIG. 6 is a front view schematically showing a roll configuration of a second coarse universal rolling mill in the rolling equipment of FIG. 3.

FIG. 7 is a front view schematically showing a roll configuration of a finishing universal rolling mill in the rolling equipment of FIG. 3. W

8

[FIG. 8A] FIG. 8A is a side view of the horizontal roll showing a state in which the lubricating oil supply device X is installed in the vicinity of the horizontal roll corner of the rough universal rolling mill shown in FIG.

FIG. 8B is a front view showing a state in which the lubricating oil supply device X is installed in the vicinity of the horizontal roll corner of the rough universal rolling mill shown in FIG.

FIG. 9 is an explanatory view showing an example of a cross-sectional shape of an unequal side unequal thick angle steel.

FIG. 10 is an explanatory diagram showing an example of a rough cross-sectional shape of a T-section steel.

[Fig. 11] Fig. 11 is a side view (left side) and front view (right side) of the end of the T-longi material, showing an example of groove processing when the ends of the T-long material are welded together. It is. BEST MODE FOR CARRYING OUT THE INVENTION

[0025]

Fig. 1 shows an example of the cross-sectional shape of the T-shaped steel of the present invention in the cross-section direction, where f is a flange, w is a web, fi is a joint between a web w and a flange f, that is, a web w This is a buillet formed at the corner composed of the flange f. In addition, A is the web length, B is the flange width, tl is the web thickness, and t2 is the flange thickness. Furthermore, rl is the arc radius of the fillet part fi (arc radius of the cross section in the section width direction), r2 is the arc radius of the corner on the inner surface side of the flange tip (arc radius of the section in the section width direction), and _{r3 is the} flange. This is the arc radius of the corner portion on the outer surface side of the tip (the arc radius of the cross section in the width direction of the section).

[0026]

The T-section steel of the present invention is a T-section steel that does not have a weld with a web height A of 150 mm or more, and the cross-sectional shape of the violet portion fi in the section width direction is a circle that contacts the web w and the flange f. It is arc-shaped and its arc radius rl (hereinafter sometimes referred to as “Builet R”) is 2 to 10 mm.

[0027]

The fact that it does not have a welded part is not a so-called welded T-section steel obtained by welding and assembling thick plates, but it is obtained by cutting the H-section steel web obtained by hot rolling in half (two divisions). It may be a so-called cut T-section steel. However, from the viewpoint of productivity and cost increase by adding a half-cutting process to the web, it is preferable to use a so-called rolled T-shaped steel obtained by processing into a T-shaped steel by hot rolling. . In addition, from the viewpoint of weldability, it is preferable that the flange thickness is a T-shaped steel that is uniform over the entire width excluding the vicinity of the bullet portion and the flange tip.

[0028]

Since the effect of the present invention is obtained by the definition of the fillet R, the web height A and the flange width B of the T-section steel are arbitrary. However, when it is used as a hull structural member, it is at least twice the web height A It is preferable that it is above. The combination of web height A and flange width B is arbitrary, for example, 250mm x 100mm, 300mm x 100mm, 300mm x 125mm, 350mm x 125mm, 400mm x 125mm 500mm x 150mm, 600mm x 150mm, 700mm x 150mm, 800mm x 150mm It can be selected by the combination of. The combination of web thickness tl and flange thickness t2 is also arbitrary. For example, the force that can be selected according to the thickness of cut T-section steel (standardized thickness of H-section steel and flange thickness) When used as a hull structural member, the flange thickness t2 is the web thickness tl Is preferably larger. In general, the web length A is less than 10 times the flange width B.

[0029]

In the T-shaped steel of the present invention, the fillet R (arc radius rl) of the fillet part fi is 2 to 10ππη, preferably 2 to 8 mm, regardless of the web length A or the flange width B. As mentioned earlier, when welding the ends of T-longi materials, the welding is performed after the butt portion is grooved. In order to avoid welding defects, a scalloping force is applied to cut out part of the web and fillet part in contact with the flange into a fan shape (see Fig. 11). If the fillet R exceeds 10 mm, the volume and width of the fillet portion will increase, so in this scalloping process, a finishing process will be performed so as not to cause a defective finish that leads to a decrease in the strength of the welded joint. The work efficiency of the scalloping process including, and the bending processability when bending the T-longi material along the hull are also reduced.

[0030]

Table 1 shows that Bullet R is 13mn! Shows the fillet cross-sectional area and fillet width of a T-steel of ~ 2mm. Here, the fillet cross-sectional area refers to the cross-sectional area of the fillet part fi (excluding the web part and the flange part) on the right side of FIG. 11 or in FIG. 1, and the fillet R is zero and the web and flange are If it is formed at right angles, the fillet cross-sectional area is zero. In addition, the fillet width refers to the length from the beginning of one side bullet portion fi to the end of the opposite fillet portion fi across the web.

[0031]

According to Table 1, when the fillet R is reduced to 10 mm, the cross-sectional area of the burette is reduced by 41% and the fillet width is 17 It turns out that it decreases by%. If the cross-sectional area and width of the billet portion to be removed in the scalloped cabinet are reduced to such a degree, the work efficiency in the scallop processing including the finishing process is greatly improved. Also, when the fillet R is reduced to 8mm, the fillet cross-sectional area is 6mm compared to the fillet R of 13mm. By reducing the fillet width by 2% and by 28%, and further reducing the bouillette radius to 5mm, the fillet area is also reduced by 85% and the fillet width by 44%.

[0032]

[table 1]

For web thickness 10 mm

[0033]

On the other hand, the T-shaped steel of the present invention is manufactured by a manufacturing method that adopts a method different from the conventional technology as will be described later, so that the fillet R can be reduced to 10 mm or less. Therefore, it is difficult to make the fillet R less than 2 mm.

[0034]

Usually, to manufacture the T-shaped steel of the present invention by hot rolling, rough and finish universal rolling mills are used, and when rolling with these universal rolling mills, the fillet portion is the roll corner portion of a horizontal roll. Rolled and molded. Therefore, if the roll corner R of the roll corner portion is reduced, the force that can reduce the fillet R. As described above with respect to Patent Document 3, simply by reducing the roll corner R, (a) the roll corner The contact condition between the flange and the inner surface of the flange becomes severe, and seizure occurs between the two, resulting in seizure flaws on the inner surface of the flange, making it impossible to produce a product shape steel of appropriate quality. (B) Roll corner As the roll wear increases, the roll corner R increases as rolling continues, and the arc shape collapses, making it impossible to form a smooth single-radius arc. With the technology, the roll corner R cannot be reduced, and as a result, the fillet R cannot be made as small as the present invention.

[0035]

On the other hand, the present inventors have specified a specific roll part during rolling of the rough rolling universal rolling mill. Even if the size of the fillet R is made sufficiently small by reducing the roll corner R of the horizontal roll by injecting rolling lubricant (lubricant) into the position (this manufacturing method will be described in detail later) It has been found that rolling can be performed without causing problems. However, even if this manufacturing method is adopted, if the roll corner of the horizontal roll is less than !!!, it is impossible to prevent the occurrence of seizure flaws on the inner surface of the flange. As a result, it is difficult to mass-produce T-shaped steel by hot rolling. For this reason, in the T-shaped steel of the present invention, the lower limit of fillet R is 2 mm.

[0036]

For the above reasons, the size of the buillet R is 2 to 10 mm in the T-shaped steel of the present invention. [0037]

The billet part has an arc shape in contact with the web and flange in the cross-sectional shape in the cross-section direction (the cross-sectional shape on the right side of Fig. 11). Here, the arc shape does not need to be a strictly accurate arc shape, but it is remarkable as seen in welded T-shaped steel and rolled τ-shaped steel 'cut T-shaped steel obtained by horizontal rolls with rough corners. When the arc force deviates, it shall be excluded. Preferably, an arc that has a radius of rl is defined as a deviation from the arc of radius rl that falls within ± 20% of rl.

[0038]

In the T-section steel of the present invention, it is preferable that the fillet R of the left and right fillet portions fi (fillet portions on both sides of the web) in FIG. 1 is constant over the entire length of the shape steel. When the T-shaped steel of the present invention is manufactured by hot rolling, the left and right fillet portions fi are rolled and formed at the roll corner portion of the horizontal roll of the universal rolling mill, so that it is possible to obtain a fillet portion fi having the same radius over the entire length. it can. That is, there is an advantage that a uniform fillet portion fi is obtained in which the joint portion such as a welded T-shaped steel is not uneven in the longitudinal direction, and the quality control of the member becomes easy. Here, if the fluctuation of fillet R is within a range of ± 20%, it can be regarded as constant over the entire length of the shape steel.

[0039]

In addition, the T-shaped steel of the present invention has four corners on the flange tip (a total of four corners on the flange tip inner surface side and flange tip outer surface side corner) to ensure the perfection of the coating. It is preferable that the cross-sectional shape in the cross-section direction of the shape of the corner of the corner is an arc shape and the arc radii r2, r3 (see FIG. 1) are 2 mm or more. The upper limit of r2 and r3 does not need to be set in particular, and there is no problem even if it reaches half of the flange thickness t2. This arc is also allowed to be slightly deformed. [0040]

Next, a production method suitable for obtaining the T-shaped steel (rolled vertical steel) of the present invention will be described.

[0041]

In this manufacturing method, a steel bar is manufactured by hot rolling using a rough universal rolling mill or a finishing universal rolling mill. Specifically, for example, T-shaped steel pieces obtained by a rough down mill (brake down mill), etc. are used as the first coarse universal mill, edger mill, second coarse universal mill, and finish universal. A steel bar is manufactured by rolling sequentially with a rolling mill. In such a manufacturing method using a rough universal rolling mill and a finishing universal rolling mill, the fillet portion fi is rolled and formed at the roll corner portion of the horizontal roll of the universal rolling mill.

[0042]

Therefore, the roll corner R (radius) of the horizontal roll of the roughing and finishing universal rolling mill is set to a dimension capable of forming the fillet R (2 to 10 mm) of the T-shaped steel of the present invention to be manufactured. During rolling on the upper universal rolling mill, rolling lubricant (lubricating oil for hot rolling) is sprayed from the lubricant supply device onto the roll corner of the horizontal roll to lubricate the horizontal roll corner. At this time, if the rolling lubricating oil is sprayed onto the flange inner surface, the seizure prevention effect is further improved, and seizure of the roll corner portion and the flange inner surface can be more effectively prevented.

[0043]

In addition, as a countermeasure to the problem that the roll corner portion temperature tends to rise as roll corner R becomes smaller and the roll is more likely to be damaged, at least on the rolling exit side of the rough universal rolling mill, Cooling water injection nozzles are arranged, and cooling water is sprayed from the cooling water injection nozzles to the horizontal roll corners to enhance cooling of the roll corners, thereby preventing excessive roll temperature rise and roll damage. Can be prevented.

[0044]

The T-section steel of the present invention having a small fillet R can be produced by the production method as described above. Needless to say, the method for manufacturing the T-shaped steel of the present invention is not limited to the above-described manufacturing method. As described above, the T-shaped steel of the present invention is most suitable as a T-longage material for hull structures, but it can also be used as a structural material in the fields of bridges and construction. Example 1

[0045] Tables 2 and 3 show examples of cross-sectional dimensions of the T-shaped steel of the present invention (hull shaped steel for hull structures). The standard external dimensions (see Fig. 1) are the web height 高 is 300 mm and the flange width B is 125 mm. The web thickness tl is 9-12 mm, and the flange thickness t2 is 16-25 mm.

[0046]

Table 2 shows that the length obtained by subtracting the flange thickness t2 from the web height A (the web tip force length to the inner surface of the flange) and the length obtained by subtracting the web thickness tl from the flange width B are constant. Inside dimension—a definite product with a difference of several millimeters in web length A and flange width B with changes in web thickness tl and flange thickness t2. Such a series of products with a fixed internal law is the distance between the vertical roll 42b on the web tip side and the horizontal rolls 41a and 41b in the second rough universal rolling mill 4 shown in FIG. 6 described later. Can be produced by rolling with a constant value. Also shown in Table 3 is an outside dimension—fixed product where the web height A and flange width B are constant—the web height even if the web thickness tl and flange thickness t2 change. A and flange width B are constant. Such a product series with a constant outer method is a second rough universal rolling mill 4 shown in FIG. 6 to be described later, in which the distance between the roll 42b on the tip side of the web and the horizontal rolls 41a, 41b is set as the web of the material to be rolled. It can be manufactured by adjusting the height to be constant and rolling.

[0047]

In Tables 2 and 3, the R dimension of each part is the arc radius rl (fillet R) of the fillet part is 8 mm, the arc radius r2 of the corner part on the inner side of the flange tip is 5 mm, and the corner part of the corner part on the outer side of the flange tip is The arc radius r3 is 3mm.

[0048]

The cross-sectional characteristics of the T-section steel of the present invention shown in Table 2 are shown in Fig. 2 in comparison with the conventional unequal side unequal thickness angle steel (NAB). In the hull structure, the shape steel is mainly used to reinforce the thick plate. In the hull design, the thick plate portion where the same stress as the shape steel is applied can be considered as a part of the shape steel. Therefore, when considering the cross-sectional performance of a section steel, the section modulus of a plate with a certain width is important. Therefore, the section modulus with a plate of 610 mm width x 15 mm thickness was used as an index here. The section modulus with a plate is calculated by calculating the second moment of section with respect to the centroid axis in the section where a plate of the specified area is joined to the outer surface of the flange of the T-shaped steel, and the value is the farthest in the section of the centroid axis force. Divided by the distance to the point.

[0049]

As shown in Figure 2, the cross-section coefficient of the T-section steel plate with web height A of 300mm and flange width B of 125mm is 300mm x 90min, 350mm x 100mm, 400mm x 100mm A series of 300 mm X 125 mm T-section steel, and 300 mm X It can be seen that 3 series of 90mm, 350mm X 100mm, 400mm X 100mm can be force par.

[0050]

[Table 2]

[0051]

[Table 3]

Sectional dimensions (mm)

Series

A B t1 t2 r1 r2 r3

300 125 300 124 9 16 8 5 3

303 124-9 19 8 5 3

300 125 10 16 8 5 3

303 125 10 19 8 5 3

303 126 1 1 19 8 5 3

306 126 1 1 22 8 5 3

306 127 12 22 8 5 3

309 127 12 25 8 5 3 [0052]

An example of production by hot rolling of the T-shaped steel (rolled vertical steel) of the present invention is shown below. The equipment configuration, rolling mill structure, roll shape, dimensions, etc. are examples, and are not limited to these.

[0053]

From a plume with a rectangular cross section of 25.0mm in thickness and 310mm in width using the rolling equipment shown in Fig. 3. T-shaped steel with a target height of 300mm in web height, 100mm in flange width, 9mm in web thickness and 16mm in flange thickness Rolled. In this T-shaped steel, the arc radius rl (fillet R) of the buillet was 8 mm. In FIG. 3, 1 is a rough shaping rolling mill, 2 is a first rough universal rolling mill, 3 is an edger rolling mill, 4 is a second rough universal rolling mill, 5 is a finishing universal rolling mill, and 6 is an intermediate rolling process. is there.

[0054]

The rough shaping rolling mill 1 is usually a double rolling mill equipped with a roll having a hole shape.

[0055]

FIG. 4 schematically shows the roll configuration of the first rough universal rolling mill 2. This roughing mill ₂ has a pair of opposed horizontal rolls 21a, 21b and a pair of opposed hard rolls 22a, 22b. Is larger than the internal dimension L (distance from the flange inner surface to the web tip on the opposite side). The side surfaces of the horizontal rolls 21a and 21b are inclined.

[0056]

FIG. 5 schematically shows the roll configuration of the edger rolling mill 3. The edger rolling mill 3 includes a pair of opposed horizontal rolls 31a and 31b, and each horizontal roll 31a and 31b has a large-diameter roll portion 33 and a small-diameter roll portion 32, respectively.

[0057]

FIG. 6 schematically shows the roll configuration of the second rough universal rolling mill 4. This second rough universal rolling mill 4 includes a pair of opposed horizontal rolls 41a and 41b and a pair of opposed hard rolls 42a and 42b. The width W2 of the roll surface of the horizontal rolls 41a and 41b The inner dimension of w is less than L (preferably less). The side surfaces of the horizontal rolls 41a and 41b that are in contact with the flange f are inclined.

[0058]

FIG. ⁷ schematically shows a roll configuration of the finishing universal rolling mill 5. The finishing mill 5 is provided with a pair of opposed horizontal rolls 51a and 51b and a pair of opposed hard rolls 52a and 52b. The sides of the horizontal roll 5 la, 5 lb are vertical. [0059]

First, a raw steel piece (not shown) carried out of a heating furnace (not shown) was first rolled into a T-shaped steel piece having a substantially T-shaped cross section by a rough shaping rolling mill 1. This T-shaped slab had a web thickness of 40 mm, a flange thickness of 75 min, a web height of 375 mm, and a flange width of 130 mm.

[0060]

Next, this T-shaped slab was subjected to 5-pass reciprocal rolling in a rolling equipment row in which the first rough universal rolling mill 2, the edger rolling mill 3, and the second rough universal rolling mill 4 were arranged close to each other.ヽ Rolled down the T-shaped billet web and flange (intermediate rolling process 6).

[0061]

In this intermediate rolling process, first, in the first rough universal rolling mill 2, as shown in FIG. 4, the entire length of the web w is reduced in the sheet thickness direction by the horizontal roll rolls 21a and 21b, and the horizontal roll roll 22a The flange f was pressed down in the thickness direction on the sides of the rolls 21a and 21b. Next, in the edger rolling mill 3, as shown in FIG. 5, the web w was guided between the large diameter roll portions 33 of the horizontal rolls 31a and 31b, and the end surface of the flange f was reduced by the small diameter roll portion 32 in the flange width direction. Next, in the second rough universal rolling mill 4, as shown in FIG. 6, most of the web w is squeezed in the thickness direction by the ice flat rolls 41a and 41b, and the hard rolls 42a and the horizontal rolls are rolled. The web f was adjusted by pressing down the flange f in the plate thickness direction on the sides of 41a and 41b, and then rolling down the tip of the web w in the web height direction with the rigid roll 42b.

[0062]

Thus, the T-shaped steel obtained in the intermediate rolling process was finish-rolled to product dimensions with a finishing universal rolling mill 5. In this finishing universal rolling mill 5, as shown in FIG. 7, the entire length of the web w is lightly reduced in the thickness direction by horizontal rolls 51a and 51b, and flanges are formed on the side surfaces of the hard roll 52a and the horizontal rolls 51a and 51b. The slope of f was shaped vertically.

[0063]

In the rough universal rolling mills 2 and 4 and the finishing universal rolling mill 5 used in the series of rolling processes as described above, the roll corner R (radius) of the horizontal roll corner is 2 rough universal rolling mills 2, For No.4, it was 9 min, and for Finishing universal rolling mill 5, it was 8 mm. Then, Figure 8A near the horizontal roll corners, established the lubricating oil supply device X as shown in FIG. 8B, the lubricating oil supply device rolling lubrication oil to the horizontal roll corners from X (for hot rolling lubricant _X l) supplied. 8A and 8B show a state in which the lubricant supply device X is installed in the first rough universal rolling mill 2, FIG. 8B is a front view, and FIG. 8A is a side view of the horizontal roll. 2 rough universal rolling mills 2 and 4 In order to perform reciprocating rolling, a lubricating oil supply device X is installed on each of the front surface (upstream side) and rear surface (downstream side) of the rolling mill, and rolling lubricating oil is injected from the lubricating oil supply device X on the rolling entry side. Then, rolling was performed in a state where the rolling lubricant was adhered to a part of the horizontal roll corner. In addition, since the finishing universal rolling mill 5 performs rolling in only one pass, the lubricating oil supply device X is installed only on the front surface (upstream side) of the rolling mill, and rolling is performed on the rolling entry side in the same manner as the rough universal rolling mill. Rolled while spraying lubricating oil. As a result of rolling while supplying the rolling lubricating oil in this manner, the roll and the inner surface of the flange were not seized, and a product having a good surface with no seizure flaws on the inner surface of the flange could be rolled. In addition, even after rolling products over lOOOOton, almost the same fillet R products with no noticeable roll corner wear could be rolled to the end. As the lubricating oil for hot rolling, those usually used for hot rolling of steel can be used without any problem. In this example, SH-105 manufactured by Daido Chemical Industry was used, but the product could be rolled without any problems.

[0064]

On the other hand, when rolling without supplying rolling lubricant, seizure flaws occurred on the inner surface of the flange, and a product with sufficient quality could not be produced.

[0065]

Next, using the rolling equipment shown in FIG. 3, a T-steel having the same dimensions as the above-described manufacturing example and having an arc radius rl (fillet R) of 5 mm in the fillet portion was manufactured.

The roll corner R (radius) of the horizontal roll corner was 6 mm for the two coarse universal rolling mills and ₅ mm for the finishing universal rolling mill. As in the production example described above, when rolling was performed while spraying the lubricating oil from the lubricating oil supply device X to the horizontal roll corner of each of the universal rolling mills 2, 4, and 5, the horizontal roll and the flange inner surface were seized. Although it could be prevented, after rolling a product of about 150 tons, cracks occurred in the horizontal roll corners of the two rough universal rolling mills 2 and 4, so rolling was interrupted. Since this crack was thought to be caused by an excessive temperature rise at the roll corner, a cooling water injection nozzle that injects cooling water at a position adjacent to the lubricating oil supply device X of the rough universal rolling mills 2 and 4 was installed as a countermeasure. Then, the horizontal roll corner portion immediately after coming into contact with the material to be rolled was water-cooled by spraying cooling water from the cooling water injection nozzle onto the horizontal roll corner portion on the rolling exit side. That is, rolling was performed by injecting rolling lubricating oil on the rolling entrance side and cooling water on the rolling exit side with respect to the horizontal drill corner. As a result, it was confirmed that there was no crack in the horizontal roll corner even when the product with an arc radius rl of 5 mm was rolled about lOOOton. Industrial applicability

[0066] The T-section steel of the present invention has an arcuate fillet and a properly reduced fillet radius compared to conventional T-sections. The work efficiency of scalloping without significantly reducing the strength of welded joints due to poor scalloping finish is greatly improved. Further, when the T-shaped steel of the present invention is used, the bending addability when bending the T-longier material along the hull is improved. Explanation of symbols

[0067]

f Flange

w web

fi Fillet section

rl Arc radius of fillet

r2 Arc radius of the corner on the inner surface of the flange tip

r3 Arc radius of the corner on the flange outer surface side

tl web thick

t2 Flange thickness

A Web height

B Flange width

1 Rough shaping rolling mill

2 First coarse universal rolling mill

3 Edger rolling machine

4 Second coarse universal rolling mill

5 Finishing universal rolling mill

6 Intermediate rolling process

21a, 21b Horizontal roll

22a, 22b firm ronole

W1 Width of horizontal roll

L Internal dimensions of the web

31a, 31b Horizontal roll

32 Small diameter roll

33 Large diameter roll 41a, 41b Horizontal ronole

42a, 42b

W2 7 Flat roll width

51a, 51b Horizontal roll

52a, 52b Hard roll

X Lubricating oil supply device xl Hot rolling lubricating oil

Claims

The scope of the claims

[Claim 1]

T-shaped steel with a web length of 150mm or more and no welds,

The cross-sectional shape of the fillet formed at the joint between the web and the flange in the cross-section width direction is an arc shape in contact with the web and the flange.

A T-section steel having a radius rl of the arc of 2 to 10 mm.

[Claim 2]

The T-section steel according to claim 1, wherein the height of the web is at least twice the width of the flange.

[Claim 3]

The T-section steel according to claim 1 or 2, wherein the T-section steel is processed into a T-section steel by hot rolling.

[Claim 4]

The T-section steel according to claim 1 or 2, wherein the radius rl of the arc of the buillet portion on both sides of the web is constant over the entire length of the section steel.

[Claim 5]

The cross-sectional shape of the corner part of the flange tip in the shape steel width direction is an arc shape,

3. The T-section steel according to claim 1, wherein the arc has a radial force of ½ mm or more.

[Claim 6]

The T-section steel according to claim 1 or 2, which is a T-section steel for ship structure.