JP5803523B2 - H-shaped steel rolling method and finishing universal rolling mill - Google Patents

Description

  The present invention relates to a method for rolling H-section steel and a finishing universal rolling mill.

  The background art of the present invention will be described by taking the production of H-section steel as a specific example. FIG. 1 shows a typical example of a conventional H-section steel rolling equipment line. This line of equipment consists of one or more RE-E groups 2 consisting of one breakdown rolling mill (BD) 1, followed by a four roll intermediate universal rolling mill (R1, R2) and an edger rolling mill (E). And 4-roll finish universal rolling mill 3 (F).

  The H-section steel manufactured by the rolling equipment row as described above has a great number of types and sizes. Furthermore, with the diversification of consumer needs, the tendency to increase the variety and size is increasing. In order to produce these various types and sizes of shape steel by the conventional rolling method, a large number of dedicated rolling rolls and dedicated guides corresponding to the shape steel are required, and the number of roll / guide replacements increases. , Time loss increases and productivity is significantly impaired.

  Therefore, in Patent Document 1 relating to rolling of shape steel, in order to create multiple sizes without frequently changing roll guides, thickened portions 7 as shown in FIG. A rolling roll mill (R3) is installed in front of a 4-roll finish universal rolling mill to reduce the thickened portion 7, and at the same time, the flange is expanded outwardly to propose a rolling method capable of widening the web height. Patent Document 2 proposes a rolling method capable of reducing the web height by applying a reduction in the web height direction with left and right vertical rolls. In this rolling method, the reduction in the web height direction may increase the vicinity of both end portions of the web from the other web thicknesses.

As described above, the thickened portion 7 may be generated at both ends of the web in rolling the shape steel. In the conventional rolling, as the roll for rolling down the flange, a roll having a radius of about 75% of the radius of the horizontal roll for rolling down the web (hereinafter referred to as a normal roll) has been used. However, in rolling of shape steel, a phenomenon called wall thickness recovery is observed immediately after the reduction, and the thickness is increased on the roll exit side than the thickness immediately below the roll. The phenomenon is particularly noticeable at both ends of the web, and it is usually difficult to completely eliminate the thickened portion at that part by the heel roll, resulting in problems such as poor shape of the web and deterioration of product accuracy. there were.

  On the other hand, the shaft center of a pair of saddle rolls called a high-precision rolling device (see Patent Document 3) having a flange is moved from the central axis of the upper and lower horizontal rolls to the exit side in the rolling direction. Although the rolling forming method was devised by prescribing the web before the flange and engaging the rolling roll by defining the diameter and the rolling reduction ratio of the web and the flange, the rolling reduction of the flange on the exit side in the rolling direction from the central axis of the upper and lower horizontal rolls However, due to disadvantages such as web buckling, the occurrence of thickened portions at both ends of the web has not been eliminated.

Japanese Examined Patent Publication No. 3-42122 JP-A-2-80102 JP-A-5-31522

  The present invention eliminates the thickened portion at both ends of the H-shaped steel web portion that occurs when the web height is divided, so that a multi-size product having a uniform web thickness from the same set of rolls is frequently used for rolls and guides. A rolling method for H-section steel and a finishing universal rolling mill that can be manufactured without recombination are provided.

The present invention has been made to solve the above problems, and the gist thereof is as follows.
(1) In rolling of H-section steel using a finishing universal rolling mill that applies a final pass to create multiple sizes by widening or reducing the web height while rolling down the thickened portions at both ends of the web,
The thickened portion is provided for web widening by the final pass, generated by the web high contraction by the final pass, and generated at the same time as the web high contraction of the final pass, Either
Used as 15 to 40% of the horizontal roll diameter as vertical roll diameter of the finish universal rolling mill,
回 転 Install the rotation axis of the roll and the rotation axis of the horizontal roll on the same plane.
A method for rolling H-section steel, wherein the thickened portions at both ends of the web are reduced in a final pass.
(2) A finishing universal rolling mill for producing a final pass by forming a multi-size H-section steel by widening or reducing the web height while reducing the thickened portions at both ends of the web,
The thickened portion is provided for web widening by the final pass, generated by the web high contraction by the final pass, and generated at the same time as the web high contraction of the final pass, Either
A horizontal roll that rolls the H-shaped steel web in the web thickness direction and widens the flange outward;
A hard roll for rolling a flange of the H-shaped steel, which is installed so as to have a rotation axis on the same plane as the rotation axis of the horizontal roll, in the flange thickness direction,
A finishing universal rolling mill characterized in that the diameter of the hard roll is 15 to 40% of the diameter of the horizontal roll.

  The present invention eliminates the thickened parts at both ends of the H-section steel web part that occurs when creating the web height, which was difficult to eliminate with the prior art, and has a uniform web thickness from the same set of rolls. Can be manufactured. Thereby, the effect that reduction of the rolling time by reduction of the number of roll sets to hold and omission of roll reassignment can be aimed at without carrying out frequent recombination of a roll and a guide is acquired.

It is explanatory drawing of a H-section steel rolling equipment row | line | column. It is explanatory drawing of the thickening part of the both ends of the web of H-section steel. It is explanatory drawing of the small diameter roll in the finishing universal rolling mill concerning embodiment of this invention. It is a graph which shows the thickness ratio of a web and a flange in case a hard roll diameter is 75% of a horizontal roll diameter. It is a graph which shows the thickness ratio of a web and a flange in case a hard roll diameter is 40% of a horizontal roll diameter. It is a graph which shows the thickness ratio of a web and a flange in case a hard roll diameter is 19% of a horizontal roll diameter. It is a graph which shows the thickness ratio of a web and a flange in case a hard roll diameter is 15% of a horizontal roll diameter. It is a graph which shows the thickness ratio of a web and a flange in case a hard roll diameter is 9% of a horizontal roll diameter. It is a graph which shows the relationship between the ratio of a hard roll diameter and a horizontal roll diameter, and a meat restoration rate.

  In the following, embodiments of the present invention will be described by taking the production of H-section steel as a specific example. First, a conventional technique will be described. FIG. 1 shows a typical example of a conventional H-section steel rolling equipment line. This line of equipment includes one breakdown rolling mill (BD) 1 and then one or more R-E groups 2, each consisting of a four-roll rough universal rolling mill (R1, R2) and an edger rolling mill (E), And 4 roll finishing universal rolling mill 3 (F). In addition, in FIG. 1, the schematic which looked at the breakdown rolling mill, the 4-roll universal rolling mill (configuration common to R1, R2), and the 4-roll finishing universal rolling mill from diagonally upward is also described for reference. .

  For example, in the rolling of the shape steel in the rolling equipment row as shown in FIG. 1, the thickened portions 7 as shown in FIG. 2 are formed at both ends of the web 9 in order to create multiple sizes without frequently changing roll guides. Is installed, and a web roll enlargement roll roll (R3) is installed in front of the 4-roll finish universal rolling mill 3 to reduce the thickened portion 7 and at the same time expand the flange 10 to the outside so that the web height can be widened. A rolling method has been proposed (see Patent Document 1). A rolling method has also been proposed in which the web height is reduced by left and right vertical rolls so that the web height can be reduced (see Patent Document 2). In this rolling method, the vicinity of both end portions of the web 9 may be larger than other web thicknesses due to the reduction in the web height direction. Note that the thickened part for web height enlargement is larger than the thickened part generated when the web height is reduced, and if the thickened part for web height enlargement can be eliminated, the thickened part in either case can be eliminated. In the following, only the elimination of the thickened portion for increasing the web height will be described. FIG. 2 is an explanatory view of the thickened portion 7 at both ends of the H-shaped steel web. The thickened portion 7 is enlarged and illustrated.

  FIG. 3 is a front view of the finishing universal rolling mill 11 according to this embodiment (FIG. 3A), and a hard roll portion (a conventional hard roll or a small diameter hard roll installation portion according to the present invention). ) Is an enlarged top view (FIG. 3B). For the sake of explanation, FIG. 3B shows both the rigid roll 4 having a conventional diameter and the small-diameter rigid roll according to the present invention (however, only the right rigid roll 26 is shown).

  As shown in FIG. 3, the finishing universal rolling mill 11 includes a pair of upper and lower horizontal rolls 22, 23 (upper horizontal roll 22, lower roll) that lowers the web 9 of the material 20 to be rolled from the vertical direction and widens the flange 10 from the inside. A horizontal roll 23) and a pair of left and right hard rolls 25, 26 for pressing the flange 10 of the material 20 to be rolled from the outside are provided. The diameters of the rigid rolls 25 and 26 (left rigid roll 25 and right rigid roll 26) according to the present embodiment are smaller than the diameters of the horizontal rolls 22 and 23. For example, the diameters of the rigid rolls 25 and 26 are as follows. The length was 15 to 40% of the diameter of the horizontal rolls 22 and 23. That is, as shown in FIG. 3B, the diameters of the hard rolls 25 and 26 (only the right hard roll 26 is shown in FIG. 3B) are smaller than the diameter of the hard roll 4 in the conventional rolling mill. ing. In addition, it is desirable to make the diameters of the above-described rigid rolls 25 and 26 15 to 40% longer than the diameters of the horizontal rolls 22 and 23 in detail with reference to FIGS. Explain the rationale.

Since the diameters of the hard rolls 25 and 26 are smaller than the diameters of the horizontal rolls 22 and 23, as shown in FIG. 3B, the hard rolls 25 and 26 (FIG. 3B) as compared with the conventional finishing universal rolling mill. Is also shown on the rigid roll 26), and the contact length between the rolled material 20 and the flange 10 is shortened. This shortened contact length 6 is illustrated in FIG. In a short rolling section, the rolling of the flange 10 in the roll bite is abruptly performed, and the change in the thickness ratio of the flange 10 with respect to the web 9 becomes large, and the thickness ratio between the web and the flange becomes uniform. The web thickness ratio and the flange thickness ratio are defined by the following two formulas (1) and (2), respectively.
Where t _web is the product web thickness (mm), t _flange is the product flange thickness (mm), H _r is the horizontal roll radius (mm), V _r is the saddle roll radius (mm), and x is directly under the roll. The rolling direction position (mm) with 0 mm as the positive rolling direction.

  As described above, according to the present embodiment, by setting the diameters of the rigid rolls 25 and 26 to be smaller than the diameters of the horizontal rolls 22 and 23, the thickness ratio between the web and the flange is uniform, and the web 9 and the flange Synchronization under 10 rolls is realized. Here, the contact length between the hard rolls 25 and 26 and the flange 10 of the material 20 to be rolled is shortened so that the reduction of the web 9 and the flange 10 is synchronized. In this case, the length is 15 to 40% of the diameter of the horizontal rolls 22 and 23. Below, with reference to FIGS. 4-8, the result of having examined the thickness ratio of the web 9 and the flange 10 of a to-be-rolled material is demonstrated.

  4 to 8 are graphs showing the thickness ratio (the product thickness) between the web 9 and the flange 10 of the material to be rolled when the hard roll diameter is shorter than the horizontal roll diameter, and FIG. FIG. 5 shows a case where the hard roll diameter is 40% of the horizontal roll diameter, FIG. 6 shows a case where the hard roll diameter is 19% of the horizontal roll diameter, FIG. When the roll diameter is 15%, FIG. 8 is a graph for the case where the hard roll diameter is 9% of the horizontal roll diameter. In addition, since it is not directly related to the point which makes the magnitude | size of a hard roll diameter small about the entrance side web thickness and entrance side flange thickness of a to-be-rolled material, a rolling direction position is 0 mm--40 mm in FIGS. The graph is shown only for the range of 0) immediately below the roll and 0 side of the upstream of rolling.

As shown in FIG. 4, for example, when the hard roll diameter is 75% of the horizontal roll diameter, which is a configuration generally used in conventional rolling equipment, the thickness ratio of the web 9 is changed. The change in the thickness ratio of the flange 10 is gradual. That is, the flange 10 constrains the elongation of the web 9 in the rolling direction. As shown in FIG. 5, when the hard roll diameter is 40% of the horizontal roll diameter, the change in the thickness ratio of the flange 10 is less gradual than in the case shown in FIG. Furthermore, as shown in FIGS. 6-8, it turns out that the change of the thickness ratio of the flange 10 becomes steep as the hard roll diameter becomes small (19% -9% of the horizontal roll diameter).

  Moreover, as shown in FIGS. 4-8, the thickness ratio of the web 9 is constant. Here, as shown in FIGS. 5 to 7, when the hard roll diameter is 40%, 19%, and 15% of the horizontal roll diameter, the hard roll diameter is 75% of the horizontal roll diameter (shown in FIG. 4). The thickness ratio of the flange 10 is closer to that in the case of (case). That is, for example, the rolling rate in the rolling direction in the case where the diameter of the rigid roll shown in FIGS. 5 to 7 is smaller than that in the conventional rolling equipment shown in FIG. The elongation of the web 9 is restrained from being restrained by the elongation of the flange 10, and the reduction in synchronization is realized.

Under the conditions shown in FIG. 5 to FIG. 7 described above, the rolls of the web 9 and the flange 10 are synchronized by reducing the diameter of the rigid roll as compared with the horizontal roll, and the web-flange is stretched in the rolling direction. Restraint is reduced. However, as shown in FIG. 8, when the rigid roll diameter is 9% of the horizontal roll diameter, the thickness ratio of the flange 10 is too large with respect to the thickness ratio of the web 9, and the case shown in FIG. Conversely, the elongation in the rolling direction of the flange 10 is constrained by the web 9. Due to this restriction, it becomes difficult to eliminate the thickened portions 7 at both ends of the web formed for different web heights.

  In rolling of shape steel, when the reduction of the web 9 and the flange 10 in the cross section is not synchronized, for example, when only the web 9 is reduced, the metal flow in the rolling longitudinal direction is caused by reduction around the web 9. Will occur. However, since the metal flow in the rolling longitudinal direction does not occur around the flange 10, the flange 10 restrains the metal flow in the rolling longitudinal direction of the web 9, thereby preventing the thickened portion 7 from being eliminated and the reduction in restoration in the cross section from being prevented. It will be. The same applies when only the flange 10 is rolled down. Therefore, by synchronizing the reduction of the web 9 and the flange 10, the restriction of the metal flow in the rolling longitudinal direction is suppressed, and the elimination of the thickened portion 7 and the reduction of restoration in the cross section are realized. In other words, the above-described synchronization under reduction is very effective for eliminating the thickened portion 7 and reducing the restoration in the cross section.

  From the knowledge obtained with reference to FIGS. 4 to 8 described above, when rolling down the material 20 to be rolled in the finishing universal rolling mill 11, the diameter of the hard roll is 15% to 40% of the diameter of the horizontal roll. By doing so, the thickness ratio between the web 9 and the flange 10 becomes closer than before, the reduction of the synchronization is achieved, and the thickened portions 7 at both ends of the web formed for different web heights are efficiently used. It can be seen that it can be resolved. Further, as the thickness ratio between the web 9 and the flange 10 approaches, synchronization of the reduction of the web 9 and the flange 10 is promoted, so the diameter of the hard roll is more preferably 15% to 25% of the diameter of the horizontal roll. desirable.

On the other hand, FIG. 9 is a graph showing the relationship between the ratio of the hard roll diameter to the horizontal roll diameter (that is, the hard roll diameter / the horizontal roll diameter, represented by 0 to 1) and the meat restoration rate (%). Specifically, when rolling is performed with the diameter of the hard roll being 9%, 15%, 19%, 40%, 75% of the diameter of the horizontal roll, the respective meat restoration rate (recovered immediately after the reduction) It is the graph which showed the ratio (%) of the thickness which has been. In addition, the graph shown in FIG. 9 illustrates the meat restoration rate when the area reduction rate (cross-sectional reduction rate) is 5%.

As shown in FIG. 9, the meat restoration rate during rolling is the lowest value (55%) when the diameter of the hard roll is 19% of the diameter of the horizontal roll, and is 9% (95 %) And 75% (100%), the values are extremely high. As described above, by setting the diameter of the rigid roll to be a predetermined diameter smaller than the diameter of the horizontal roll, the elongation in the rolling direction of the material to be rolled increases with the synchronization of the web 9 and the flange 10 under the reduction, This is because the meat restoration rate decreases.

Further, from the graph shown in FIG. 9, when the hard roll diameter is 15%, 19%, and 40% of the horizontal roll diameter, the hard roll diameter, which is a general roll diameter ratio in the conventional rolling equipment, is horizontal. The meat restoration rate is reduced as compared with 75% of the roll diameter. That is, as described above, by setting the rigid roll diameter to 15% to 40% of the horizontal roll diameter, synchronization between the web 9 and the flange 10 is promoted and the meat restoration rate can be reduced. It turns out that it is possible.

As described above, according to the knowledge that can be seen from FIGS. 4 to 8 and FIG. 9, the diameter of the hard roll is set to a predetermined diameter smaller than the diameter of the horizontal roll (that is, 15% to 40% of the horizontal roll diameter). In comparison with the above, the synchronization of the web 9 and the flange 10 is reduced, and the thickened portions 7 formed at both ends of the web 9 can be efficiently eliminated with the same set of rolls, and the web height is different. In addition, a product having a uniform web thickness can be manufactured. In addition, it is possible to reduce the number of roll sets to be held and to omit roll reassignment, so that the rolling time can be shortened.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the form of illustration. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

As an example of the present invention, the change in the thickness of the thickened portion during rolling was measured when rolled with a conventionally used hard roll and when rolled with a small diameter hard roll according to the present invention. did. As the material to be rolled, such a material was used that a H-shaped steel having a product dimension of 600 mm in web height, 300 mm in flange width, 12 mm in web thickness, and 28 mm in flange thickness was manufactured. Moreover, the thickened part (cross-sectional area 800mm < ² >) for expanding web height is formed in the both ends of the web of a to-be-rolled material. A conventionally used hard roll having a roll diameter of φ1000 mm was used, and a small diameter roll according to the present invention having a roll diameter of φ250 mm was used. The horizontal roll diameter at this time was φ1315 mm in all cases. That is, when the small-diameter hard roll according to the present invention is used, the hard roll diameter is about 19% of the horizontal roll diameter (corresponding to the case of FIG. 6 described in the above embodiment). Table 1 below shows the thickness of the thickened portion and the web thickness at that time in each case.

  As shown in Table 1, when rolling the material to be rolled with thickened portions formed at both ends of the web, when rolling with a conventionally used hard roll, the thickness is 2.26 mm before rolling. The formed thickened part became 2.00 mm in thickness after rolling. On the other hand, when rolling is performed with a small roll (about 19% of the horizontal roll diameter) according to the present invention, the thickened portion formed with a thickness of 2.26 mm before rolling has a thickness of 1 after rolling. 70 mm. From this result, by making the hard roll diameter a small diameter roll that is about 19% of the horizontal roll diameter, the thickened part formed in the material to be rolled can be effectively eliminated by rolling compared to the conventional one. In the example, an improvement of about 15% was observed. Therefore, by performing rolling using the small-diameter hard roll according to the present invention, a product having a more uniform web thickness distribution than before can be produced. In addition, when manufacturing products with different web heights (for example, H-section steel series), it is not necessary to use a plurality of roll sets, and it is possible to reduce the number of roll sets to be held and omit roll reassignment. Thereby, shortening of rolling time and efficiency of rolling are achieved.

  In addition, according to the graph of FIG. 9 demonstrated in the said embodiment, when a rigid roll diameter is made into a small diameter roll which is about 19% of a horizontal roll diameter, on the other hand, the meat restoration rate is 55%. In the present embodiment, as described in Table 1, about 75% (1.70 / 2.26 × 100 = about 75%) is restored. This is because the graph of FIG. 9 shows the meat restoration rate when the area reduction ratio under reduction is 5%, whereas the measurement in this example shows that the area reduction ratio under reduction is 2%. It is because it went.

  The present invention can be applied to a rolling method for H-section steel and a finishing universal rolling mill.

DESCRIPTION OF SYMBOLS 1 ... Breakdown rolling mill 2 ... RE group 3 ... Finishing universal rolling mill (conventional)
4 ... Hard roll (conventional)
6 ... Contact length to be shortened 7 ... Thickened part 9 ... Web 10 ... Flange 11 ... Finishing universal rolling mill 20 ... Rolled material 22 ... Upper horizontal roll (horizontal roll)
23 ... Lower horizontal roll (horizontal roll)
25 ... Left roll (hard roll)
26 ... Right roll (hard roll)

Claims (2)

In rolling the H-section steel using a finishing universal rolling mill that applies a final pass to create multiple sizes by widening or reducing the web height while rolling down the thickened parts at both ends of the web,
The thickened portion is provided for web widening by the final pass, generated by the web high contraction by the final pass, and generated at the same time as the web high contraction of the final pass, Either
Used as 15 to 40% of the horizontal roll diameter as vertical roll diameter of the finish universal rolling mill,
回 転 Install the rotation axis of the roll and the rotation axis of the horizontal roll on the same plane.
A method for rolling H-section steel, wherein the thickened portions at both ends of the web are reduced in a final pass. A finishing universal rolling mill that applies a final pass to create a multi-size H-section steel by widening or reducing the web height while reducing the thickened portions at both ends of the web,
The thickened portion is provided for web widening by the final pass, generated by the web high contraction by the final pass, and generated at the same time as the web high contraction of the final pass, Either
A horizontal roll that rolls the H-shaped steel web in the web thickness direction and widens the flange outward;
A hard roll for rolling a flange of the H-shaped steel, which is installed so as to have a rotation axis on the same plane as the rotation axis of the horizontal roll, in the flange thickness direction,
A finishing universal rolling mill characterized in that the diameter of the hard roll is 15 to 40% of the diameter of the horizontal roll.