CN102215989A

CN102215989A - Process for producing t-bar steel and series of rolling devices

Info

Publication number: CN102215989A
Application number: CN2009801454102A
Authority: CN
Inventors: 高岛由纪雄; 山口阳一郎; 高桥英树
Original assignee: NKK Corp
Current assignee: JFE Steel Corp; JFE Engineering Corp
Priority date: 2008-11-20
Filing date: 2009-11-19
Publication date: 2011-10-12
Anticipated expiration: 2029-11-19
Also published as: KR101043564B1; KR20110028553A; JP2010149181A; JP4544371B2; WO2010058861A1; CN102215989B

Abstract

A process for producing T-bar steel which includes an intermediate rolling step, in which the web and flange of a T-shaped steel bar roughly formed into a T shape are rolled, and a finishing step, in which the T-shaped steel bar obtained in the intermediate rolling step is finish-rolled into the shape of a product. The intermediate rolling step comprises: a rolling step using a first universal roughing mill, wherein upper and lower horizontal rolls reduce the entire upper and lower surfaces of the web in the thickness direction; an edger rolling step in which the edge faces of the flange are reduced; and a rolling step using a second universal roughing mill, wherein upper and lower horizontal rolls, each having a roll surface that is the same width as the intended inner height of the web and also having a corner which is located on the web-tip side and has been processed into a shape that does not roll the web surface, are used to reduce the upper and lower sides of the web in the thickness direction, excluding an area near the tip. Simultaneously with this rolling, one of right and left vertical rolls is used to reduce the edge face of the web in the height direction of the web, while keeping the periphery of the vertical roll in contact with the horizontal rolls, while the other vertical roll is used to reduce the flange in the thickness direction thereof.

Description

The manufacture method of T-steel and rolling equipment group

Technical field

The present invention relates to the manufacture method and the rolling equipment group of T-steel (T-bar) by hot rolling.

Background technology

The cross sectional shape of T-steel has been shown among Figure 12.T-steel 10 is that the cross section that is formed by web (web) 11 and the edge of a wing (flange) 12 is the shaped steel of T word shape, uses widely in fields such as shipbuilding, bridges.T-steel is fabricated to the finished product of various sizes according to its purposes, service condition, use location etc.

Normally used T-steel is of a size of web height: about 200～1000mm, web thickness: about 8～25mm, web inside dimensions (inner height of web): about 190～980mm, flange width: about 80～300mm, the thickness of the edge of a wing: about 12～40mm.And, being used for the T-steel of shipbuilding, web height mostly is more than 2 times of flange width greatly.

In addition, even web height and flange width are about equally, also intensity is as required selected the T-steel of the web thickness a plurality of sizes different with edge of a wing thickness, is applied to structure.As shown in figure 13, sometimes use the benchmark of side dimension (the outer height of web) Ao (identical) of inside dimensions Ai with the web of web as web height with the web height among Figure 12, even it is constant that the also equal situation of change in size web inside dimensions Ai is called the web inboard, it is constant that the situation that web outside size Ao is equal is called web outside.Inboard when constant at web, shown in Figure 13 (a), if edge of a wing thickness t f is changed to tf1, tf2, tf3, then because Ai is constant, Ao is changed to Ao1, Ao2, Ao3.In addition, when web outside was constant, shown in Figure 13 (b), if edge of a wing thickness t f is changed to tf1, tf2, tf3, then because Ao is constant, Ai was changed to Ai1, Ai2, Ai3.When size for connection is different in the longitudinal direction T-steel, under the inboard constant situation of web, the inner surface on the edge of a wing (face of web side) is in equal height, and the outer surface on the edge of a wing produces step.On the contrary, under the constant situation of web outside, when connecting in the longitudinal direction, the outer surface on the edge of a wing produces step in the height that equates at inner surface.Use the T-steel of which kind of type, select from the angle of application property according to purposes and use position.

T-steel is generally with 12 welding of web 11 and the edge of a wing and manufacture, but also proposed the technology that goes out T-steel by rolling and integrally formed.For example, to make web thickness, edge of a wing thickness, web height and flange width is the T-steel of various sizes for efficient, proposed in roll the equipment of hot rolling (for example patent documentation 1) that has respectively disposed a universal rolling machine (universal mill) in operation and the finish rolling operation.

Figure 14 shows the one example, has: thick moulding roll mill 1, and it is rolling blank steel billet of taking out of from heating furnace (not shown) back and forth, and the cross section dumming is T shape roughly; Thick universal rolling machine 2, it is used for will be that roughly the T-steel base (not shown) of T shape shape is configured as the roughly T-steel of finished size by this thick moulding roll mill 1 dumming; Edging mill (edger mill) 3 is arranged near the downstream of thick universal rolling machine 2 (Figure 14 (a)); With smart universal rolling machine 5.The rolling process that is undertaken by thick universal rolling machine 2 and edging mill 3 rolls operation in being, the rolling process that is undertaken by smart universal rolling machine 5 is the finish rolling operation.

In Figure 14 (b), schematically show the structure of thick universal rolling machine 2, in Figure 14 (c), schematically show the structure of edging mill 3, in Figure 14 (d), schematically show the structure of smart universal rolling machine 5.Thick universal rolling machine 2 has horizontal roll (horizontal roll) 21a, 21b and perpendicular roll (vertical roll) 22a, 22b, in addition, smart universal rolling machine 5 has

horizontal roll

51a, 51b and

perpendicular roll

52a, 52b, by adjusting mill opening (roll gap) separately, even do not change roll, also billet rolling can be become the finished product of various edges of a wing thickness, web thickness.Edging mill 3 has

edger roll

31a, 31b, and they are made of large-diameter portion 33 and minor diameter part 32, utilizes minor diameter part 32 to depress the end face on the edge of a wing 12, thereby can adjust flange width.

The method of using 3 thick roll mills and 3 edging mills efficiently to make T-steel is disclosed in patent documentation 2.In this technology, after roughing system, depress the end face 11a of web 11 and the end face 12a on the edge of a wing 12 simultaneously by 3 edging mills shown in Figure 15, also the height of web 11 is adjusted.

And, the manufacture method of the hot roll T shaped steel with following feature is disclosed in patent documentation 3, promptly, the thick shaped blooms of T-steel is carried out reciprocal when rolling at least 2 universal rolling machines by arranged in series, shown in Figure 16 (a) and Figure 16 (b), depress the web and the edge of a wing of this thick shaped blooms to thickness direction by a universal rolling machine UR, the edge of a wing of depressing described thick shaped blooms to width by another universal rolling machine UF, perhaps, simultaneously depress the edge of a wing and depress web to short transverse to width, wherein, the thick shaped blooms of T-steel carries out roughing system to steel billet and is shaped to.

In addition, following technology is disclosed in patent documentation 3, promptly, in carrying out, rolls the thick shaped blooms to T-steel and after T-steel carried out moulding, by carrying out finish rolling, make T-steel, wherein, the thick shaped blooms of T-steel carries out roughing system by thick roll mill BD to steel billet and is shaped to, roll in described for carrying out back and forth rolling to this thick shaped blooms by at least one thick universal rolling machine UR and at least one the double formula roll mill E that is adjacent configuration, depress the web thickness of this thick shaped blooms and edge of a wing thickness and the web height of this thick shaped blooms is adjusted by thick universal rolling machine, and depress the flange width of thick shaped blooms and depress the end thickness of web by double formula roll mill, described finish rolling is to described edge of a wing thickness by smart universal rolling machine UF, at least one size in described web thickness or the described web height is adjusted (Figure 17).

The special public clear 43-19671 communique of patent documentation 1:JP;

Patent documentation 2:JP spy opens clear 57-4301 communique;

Patent documentation 3:JP spy opens the 2007-331027 communique.

Summary of the invention

Utilize under the situation that rolling equipment shown in Figure 14 is rolled, in roll in the thick universal rolling machine 2 of operation, utilize

horizontal roll

21a, 21b to depress web 11 along the thickness of slab direction of the web 11 of T-steel base H, and the thickness of slab direction along the edge of a wing 12 of T-steel base (being rolled part) H between perpendicular roll 22a and

horizontal roll

21a, 21b is depressed the edge of a wing 12.The side of not depressing the perpendicular roll 22b of the edge of a wing 12 1 sides and

horizontal roll

21a, 21b joins and disposes, when depressing the edge of a wing 12, the side that the mode that does not move with

horizontal roll

21a, 21b by the axial power that acts on

horizontal roll

21a, 21b from perpendicular roll 22a is pushed horizontal roll 21a, 21b.In addition, utilize near the edging mill 3 the downstream be arranged on thick universal rolling machine 2, depress the end face of width on the edge of a wing 12 of T-steel base H, adjust the width on the edge of a wing 12.In the finish rolling operation, by smart universal rolling machine 5, be shaped as the edge of a wing 12 vertical between

horizontal roll

51a, 51b and perpendicular roll 52a, the 52b, web is not depressed on its short transverse, thereby finishes the hot rolling of T-steel.

That is, under the situation of having used rolling equipment shown in Figure 14, in roll in the operation, use thick universal rolling machine 2 to adjust web thickness and edge of a wing thickness, and, depress edge of a wing end face by edging mill 3 and adjust flange width, but, do not use roll to depress web along the short transverse of web.Therefore, the height that produces web not necessarily forms the situation of target size, in addition, web leading section (the end face 11a of the web 11 among Figure 12) at cross sectional shape (perpendicular to the cross sectional shape of the length direction of finished product, below identical) go up to form circular-arcly, be undesirable as finished form.Though also have after hot rolling by the countermeasure with the leading section cut-out formation finished product of web such as gas cutting, slitting shears, but after hot rolling, append the cut-out operation in this case, thereby make the manufacturing cost of T-steel increase, makes become during required long-term (producing delay at delivery date etc.).

In patent documentation 1, put down in writing following technology, promptly, cut-out portion is set on the horizontal roll of smart universal rolling machine, shaping (Figure 21 of patent documentation 1 and Figure 22) is carried out in the end that cuts off web in the finish rolling operation, but because can in cut-out portion, produce overlap (bur), fillet (shear droop), so can not obtain the good finished product of cross sectional shape.

Utilize and disclosedly in the patent documentation 2 depress the method for the end face 12a on the end face 11a of web 11 and the edge of a wing 12 simultaneously, also can adjust web height by 3 edging mills.But only the end face of web 11 is limited when edging.Therefore, in the big situation of web height, when making the T-steel of the little size of web thickness, if will depress the web end face powerfully, then web 11 produces and buckles, and can not adjust web height accurately.Especially for being the shipbuilding T-steel of the size more than 2 times of flange width as web height, existing to be easy to produce and buckle and make the problem of the deterioration in accuracy of web height.

With respect to this, the milling method of patent documentation 3 records utilizes the perpendicular roll of the second universal rolling machine shown in Figure 16 (b) to depress web along short transverse, thereby the web front end is shaped and adjustment web height size.But though utilize this universal rolling machine to play the effect of depressing flange width and web front end simultaneously, the reduction in thickness on the web and the edge of a wing is had to little of a few percent degree.This is because the step-like horizontal roll that has minor diameter part and large-diameter portion owing to use is depressed flange width, thereby need use the perpendicular roll with minor diameter part in edge of a wing side, can not utilize this perpendicular roll to depress two ends, the edge of a wing, and produce step on the thickness of the edge of a wing.In addition, by depressing flange width, the thickness of edge of a wing front end increases, thereby the step on the thickness of the edge of a wing is bigger, produces the possibility height that folds into defective blemish such as (flaw) at edge of a wing outer surface.And, though be provided with 2 universal rolling machines, in fact only depress thickness by a universal rolling machine according to the above structural problem of the second universal rolling machine, exist the pass number to become many problems.

In addition, in the universal rolling machine UF of Figure 16, the perpendicular roll of one side depress the edge of a wing and the rolling counter-force that produces act on horizontal roll axially, but because the perpendicular roll of web front not with the contacts side surfaces of horizontal roll, so can not be by the axial load of perpendicular roll support horizontal roll.That is, effectively depress under the situation of edge of a wing thickness,, can not strengthen edge of a wing reduction ratio because be difficult to the axial load of several thousand kN of supporting role on horizontal roll.

And, owing to think that the inclination angle on the edge of a wing in rolling in preferred (makes edge of a wing portion under the situation of web level with respect to the inclination angle of vertical direction.Be equivalent to α-90 ° of Figure 11) be below 5 degree, thereby in the time will utilizing the second universal rolling machine effectively to depress edge of a wing thickness, the contact length of edge of a wing inner surface and horizontal roll side is elongated, also has the problem that is easy to produce defective because of the slip of roll and rolled parts on the inner surface of the edge of a wing.

On the other hand, in the thick universal rolling machine of putting down in writing in the patent documentation 3 shown in Figure 17 of use and another method of double formula roll mill, thick universal rolling machine is that one thereby pass number are many, wish that in addition making the angle on the edge of a wing is below above 5 degree of 0 degree, therefore exists the problem that is easy to produce defective on the inner face of the edge of a wing.

The present invention proposes in order to solve the above problems, its purpose is the manufacture method and the rolling equipment group that provide following, the shape that described manufacture method is used to make the web leading section well and obtain the web height of expectation accurately and is made T-steel with few pass number efficiently.

Problem of the present invention can realize by following means.

(1) a kind of manufacture method of T-steel comprises: in roll operation, be that the web and the edge of a wing of the T-steel base of T shape shape is rolled to dumming; And finish rolling operation, carry out to form the finish rolling of finished form by the T-steel base that rolls the operation acquisition in described, it is characterized in that, rolling operation in described comprises: the rolling process that is undertaken by the first thick universal rolling machine, wherein, horizontal roll is up and down depressed whole of top and bottom on the thickness of slab direction of web; The flanging operation is depressed the end face on the edge of a wing; Reach the rolling process that is undertaken by the second thick universal rolling machine, wherein, use the width of roll outer peripheral face to equate with target web inside dimensions and the bight of web leading section side be processed to not rolling web face shape about horizontal roll, depress web near leading section the top and bottom of thickness of slab direction, and about perpendicular roll in the perpendicular roll of a side depress the edge of a wing along the thickness of slab direction on the edge of a wing, the perpendicular roll of opposite side make the outer peripheral face contact up and down horizontal roll and depress the end face of web along the short transverse of web.

(2) as the manufacture method of above-mentioned (1) described T-steel, it is characterized in that, in the rolling process that is undertaken by the described second thick universal rolling machine, the outer peripheral face of the perpendicular roll of depressing the web end face is contacted with up and down horizontal roll and adjust aperture between the perpendicular roll of opposite side and the horizontal roll side up and down, make the constant and T-steel of a plurality of sizes that edge of a wing thickness is different of web inside dimensions thus.

(3) a kind of rolling equipment group of T-steel, the T-steel base that with the dumming is T shape shape is as being rolled part, rolling this is rolled the web and the edge of a wing of part, it is characterized in that, dispose following roll mill and constitute: the first thick universal rolling machine, the width with roll outer peripheral face is greater than the described horizontal roll up and down that is rolled the target web inside dimensions of part; Edging mill is depressed the described end face that is rolled the edge of a wing of part; And the second thick universal rolling machine, have up and down horizontal roll and about perpendicular roll, in the described horizontal roll up and down, the width of roll outer peripheral face equates with the described target web inside dimensions that is rolled part, and the bight of web front is processed to the shape of not rolling web face, in the perpendicular roll about described, the perpendicular roll of one side is depressed this edge of a wing along the thickness of slab direction on the edge of a wing, and the perpendicular roll of opposite side makes the outer peripheral face of this perpendicular roll contact with up and down horizontal roll and depresses the end face of web along the short transverse of web.

The invention effect

Manufacture method and rolling equipment group according to T-steel of the present invention, by following effect, can obtain just can make the shape of web leading section good and can obtain the effective manufacture method and the rolling equipment group of the T-steel of the web height expected accurately, industrial extremely useful by hot rolling.

1. roll the web thickness of operation and depressing of edge of a wing thickness because utilize in this two sides enforcement of the first and second thick universal rolling machines, so compare with the situation of using a thick universal rolling machine rolling thickness, can increase the web thickness of per 1 pass and the drafts of edge of a wing thickness, thereby the minimizing pass improves rolling efficiency.In addition, by with many of any roll mill configurations at least in the first thick universal rolling machine, edging mill, the second thick universal rolling machine, can further improve rolling efficiency.

2. by the second thick universal rolling machine, the periphery of perpendicular roll is contacted with a side of not depressing edge of a wing thickness (web front) of horizontal roll, support because of depressing the axial rolling counter-force that acts on horizontal roll that edge of a wing thickness produces, and depress the end face of web along short transverse, thereby can prevent moving axially of horizontal roll, and can the good T-steel of rolling dimensional accuracy.

3. because the bight of the web front of the employed horizontal roll of the second thick universal rolling machine is processed to the shape of not rolling web face,, can obtain good web front end shape so also can not form enation even depress the web front end.

Description of drawings

Fig. 1 is the figure of an example of the configuration of the expression rolling equipment of implementing the T-steel that the present invention uses.

Fig. 2 is the figure that the structure of the first thick universal rolling machine of implementing the present invention's use is described, Fig. 2 (a) is the one example, and Fig. 2 (b) is the schematic diagram of other examples of explanation.

Fig. 3 is the schematic diagram of an example of the explanation structure of implementing the edging mill that the present invention uses.

Fig. 4 is the schematic diagram of an example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Fig. 5 is the schematic diagram of the another one example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Fig. 6 is the schematic diagram of another example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Fig. 7 is the schematic diagram of another example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Fig. 8 is the schematic diagram of another example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Fig. 9 is the schematic diagram of another example of the explanation structure of implementing the second thick universal rolling machine that the present invention uses.

Figure 10 is the schematic diagram of an example of the explanation structure of implementing the smart universal rolling machine that the present invention uses.

Figure 11 is the schematic diagram of explanation in the shape for lugs of rolled parts web front end generation.

Figure 12 is the cutaway view of the cross sectional shape of expression T-steel.

Figure 13 is the figure of the size shape of the inboard constant and T-steel that the outside is constant of expression, and Figure 13 (a) is the figure of the inboard constant T-steel of expression, and Figure 13 (b) is the figure of the constant T-steel in the expression outside.

Figure 14 is the figure that represents the rolling equipment of T-steel in the past, Figure 14 (a) is the allocation plan of roll mill, Figure 14 (b) is the figure of the structure of the thick universal rolling machine of explanation, and Figure 14 (c) is the figure of the structure of explanation edging mill, and Figure 14 (d) is the figure of the structure of the smart universal rolling machine of explanation.

Figure 15 is the figure of structure that represents the edging mill of T-steel in the past.

Figure 16 is the figure that represents the structure of the universal rolling machine in the milling method of T-steel in the past, and Figure 16 (a) is the figure of the structure of the expression first universal rolling machine, and Figure 16 (b) is the figure of the structure of the expression second universal rolling machine.

Figure 17 is the figure of the milling method of the expression T-steel in the past that uses thick universal rolling machine, edging mill, smart universal rolling machine.

The specific embodiment

Below, use accompanying drawing to describe the embodiment of manufacture method of the present invention and rolling equipment group in detail.

Fig. 1 shows an example of rolling equipment group of the present invention, in the drawings, and the thick moulding roll mill of 1 expression, 2 expressions, the first thick universal rolling machine, 3 expression edging mills, 4 expressions, the second thick universal rolling machine, 5 expression finishing mills.The blank steel billet (not shown) of taking out of from heating furnace (not shown) is by the thick moulding roll mill 1 rolling T-steel base that is roughly T shape for cross sectional shape.Can utilize known equipment as thick moulding roll mill 1, for example for the double formula roll mill of the roll with pass has been installed.Utilize the rolling T-steel base that obtains of rolling equipment group, depress the web and the edge of a wing (in roll operation), wherein, the rolling equipment group is that the first thick universal rolling machine 2, edging mill 3 and the second thick universal rolling machine 4 form near configuration.

Fig. 2 (a) shows the schematic diagram of the structure of the explanation first thick universal rolling machine 2.The first thick universal rolling machine 2 has at the horizontal roll 21a, the 21b that rotate on the trunnion axis and the perpendicular roll 22a, the 22b that rotate on vertical axis.

Horizontal roll

21a and 21b dispose in opposite directions, and

perpendicular roll

22a and 22b dispose in opposite directions.In the present invention, make the target inside dimensions L (distance from edge of a wing inner surface to web leading section) of width (depressing the width of the face) W1 of the roll outer peripheral face of

horizontal roll

21a, 21b greater than web 11.Preferably, form web 11 target inside dimensions L about 105～150%.

In the first thick universal rolling machine 2, by

horizontal roll

21a, 21b along whole on the short transverse of depressing web 11 as the thickness of slab direction of the web that is rolled part H 11 of T-steel base, the side that utilizes perpendicular roll 22a and

horizontal roll

21a, 21b along the edge of a wing 12 thickness of slab direction depress the edge of a wing 12.Come web 11 is carried out the thickness of slab adjustment by the aperture of adjusting

horizontal roll

21a, 21b, come the thickness of slab adjustment is carried out on the edge of a wing 12 by the aperture between the side of adjusting perpendicular roll 22a and horizontal roll 21a, 21b.When depressing the edge of a wing 12, because do vertically in order to power from the side of the side of

horizontal roll

21a, 21b by perpendicular roll 22a, so preferably make on the perpendicular side of roll 22b, so that

horizontal roll

21a, 21b can not move vertically by the opposite side that is pressed in horizontal roll 21a, 21b.In addition, the side of perpendicular roll 22b and the horizontal roll pushed by perpendicular roll 22b also can form the perpendicular shape that does not tilt shown in Fig. 2 (b).

Fig. 3 shows the schematic diagram of the structure of explanation edging mill 3.Edging mill 3 has

edger roll

31a, 31b,

edger roll

31a, 31b have big footpath roll portion 33 and path roll portion 32 on horizontal axis, 33 guiding of big footpath roll portion are rolled the web 11 of part H, roller surface (the depressing face) 32a of path roll portion 32 along the edge of a wing 12 width depress the end face 12a on the edge of a wing 12.The roller diameter of preferred big directly roll portion 33 and the roller diameter of path roll portion 32 are adjusted in the process of the end face 12a that passes through the path roll portion 32 rolling edges of a wing 12, greatly the gap that has a little between the top and bottom of the thickness of slab direction of the roller surface of footpath roll portion 33 and web 11.By the gap of a little is set, the unnecessary rolling counter-force of generation when eliminating big footpath roll portion 33 and contacting with web, and big directly roll portion 33 carries out work as guiding piece, the effect of the web face that makes the up and down length unanimity till the edge of a wing front end up and down can be produced, thereby dimensional accuracy can be improved.Preferred gap is below the 2mm.

Fig. 4 shows the schematic diagram of the structure of the explanation second thick universal rolling machine 4.In addition, Fig. 5～Fig. 9 also is the schematic diagram of the structure of the thick universal rolling machine 4 of explanation, and is as described below, is the distortion of Fig. 4.The second thick universal rolling machine 4 has at the horizontal roll 41a, the 41b that rotate on the trunnion axis and the perpendicular roll 42a, the 42b that rotate on vertical axis.

Horizontal roll

41a and 41b dispose in opposite directions, and

perpendicular roll

42a and 42b dispose in opposite directions.In the second thick universal rolling machine 4, adjust the mill opening of

horizontal roll

41a, 41b and adjust the thickness of slab of web 11, and the aperture between the side of the side by adjusting perpendicular roll 42a and

horizontal roll

41a, 41b is adjusted the thickness of slab on the edge of a wing 12.At this moment, move vertically, make the side face c of perpendicular roll 42b contact and dispose with the side b of the opposite side of

horizontal roll

41a, 41b in order not make

horizontal roll

41a, 41b.

The width of the roll outer peripheral face of

horizontal roll

41a, 41b (depressing the width of face) W2 form with web 11 in roll operation about equally value of target inside dimensions L (distance till the end face 11a from edge of a wing inner surface to the web leading section) (be W2＜W1 also can).In addition, roll the target inside dimensions L in the operation in the web 11, the increase of the small web height that the smart universal rolling machine that consider utilizing becomes last rolling process produces is preferably formed usually to respect to the value about the short 0～5mm of inside dimensions of the T-steel in finished product stage.That is, the width W 2 of the face of circumferentially depressing of preferred levels roll 41a, 41b is with respect to the value about the little 0～5mm of web inside dimensions of T-steel finished product.Because the width of

horizontal roll

41a, 41b is the size that equates with the target inside dimensions L of web 11, thus the preceding end in contact of perpendicular roll 42b and web 11 and depressing, thus can adjust the shape of the height and the end face 11a of web 11.

And, in the present invention, the bight a of the web front of

horizontal roll

41a, 41b is carried out Machining of Curved Surface, chamfering, step etc. perhaps is set.Usually carry out circular-arc processing to being assembled in the bight that H shaped steel etc. has a horizontal roll up and down on the thick universal rolling machine of shaped steel on the edge of a wing, cooperate the finished form of rolling shaped steel.But rolling to T-steel wished that the web front end is configured as the right angle, thereby from cooperating the viewpoint of finished size same, thinks that the bight of web front does not need to carry out circular-arc processing.But when the web front end was depressed by perpendicular roll 42b, the volume that produces the pressure part made the distortion of web thickness increase in the cross section.And, do not have in the bight under the situation in space, the distortion of the web front end that is depressed flows to the little gap between the side b of opposite side of the side face c of perpendicular roll 42b and

horizontal roll

41a, 41b, as shown in figure 11, front end at web forms enation 15, and the rolling meeting that utilizes smart universal rolling machine to carry out produces defectives such as sandwiching defective.

For fear of this defective, in the present invention, the horizontal roll bight is processed into the shape of not rolling web face and is rolled.Thus, because between the side face of the face of circumferentially depressing of

horizontal roll

41a, 41b web 11 front ends near and perpendicular roll 42b, be formed with big space, so form local deformation (projection 15) in little gap when the end face 11a that has prevented at web is depressed.

As concrete example, the shape of the bight a of

horizontal roll

41a, 41b forms by circular-arc processing (Fig. 4, Fig. 7), chamfer machining (Fig. 5, Fig. 8) or step processing (Fig. 6, Fig. 9) and waits the shape that forms, and guaranteeing not increases the space that the variant part of web face of thickness of slab direction of the web of generation is rolled to the thickness because of the web front end.Circular arc also can be an elliptic arc, and in addition, the central angle of circular arc and elliptic arc is not limited to 90 degree, can suitably select.In addition, the angle of chamfering is not limited to 45 degree, can suitably select.When chamfering and step are set, preferably the bight is rounded.

Usually, under the situation of circular-arc processing, implementing arc radius is the above processing of 20mm, under the situation of chamfer machining, implements the above processing of C20, thereby can prevent to produce enation.In addition, preferably add man-hour carrying out step, the width of step part is formed more than the 20mm.On the other hand, preferred processing dimension on be limited to make web 11 in roll the target inside dimensions L in the operation the web face more than 70% be rolled.That is, the width W 2 that is preferably with respect to the roll outer peripheral face of

horizontal roll

41a, 41b is in 30%.Thus, when utilizing perpendicular roll 42b along the end face of the rolling web 11 of the short transverse of web, utilize

horizontal roll

41a, 41b (promptly along the major part of the rolling web 11 of thickness of slab direction of web, near leading section), even thereby utilize perpendicular roll 42b to depress the end face 11a of web leading section, web 11 can not buckled yet.

In addition, under the situation of the shape that the horizontal roll bight is formed not rolling web face, the web end side of horizontal roll forms the opening greater than web thickness.The A/F d of preferred this opening is (a web thickness+10mm)～(about web thickness+200mm).Be limited to more preferably (about web thickness+100mm).Even the shape except above-mentioned shape, the width of also preferred non-rolling portion: 30% of 20mm～L, and d is in above-mentioned scope.

The side b of the close web front end of horizontal roll 41a (41b) can be vertical shown in Fig. 4,5,6 both, also can be shown in Fig. 7,8,9, similarly tilt with the side of edge of a wing side, preferably with the angled θ of vertical: 5＜θ≤10 °.Be provided with under the situation of inclination, consistent with this angle of inclination and in the periphery of perpendicular roll 42b the inclination of equal angular is set also, the width center that forms with roll crown is the laterally zygomorphic chevron shape of summit and the hypotenuse with inclination.Wherein, be provided with the blunt end part of width at the width center of the roll crown of depressing the web front end greater than the web thickness that is rolled part H.

In being undertaken, roll in the operation, carry out back and forth rolling till obtaining to carry out the shape of finish rolling by the first above-mentioned thick universal rolling machine 2, edging mill 3 and the second thick universal rolling machine 4.Preferably utilize the first and second thick universal rolling machines, the reduction ratio that carries out web thickness and edge of a wing thickness be 10～30% rolling.Wherein, it is rolling below 10% that the specific pass of the last roll mill that also can roll in end etc. carries out reduction ratio, does not perhaps depress and rolled parts is passed through etc.

In addition, when utilizing the second thick universal rolling machine 4 along the rolling web 11 of thickness of slab direction, it is poor to produce thickness of slab in the part of being depressed by horizontal roll 41a, 41b and near the part (the web leading section 11a) that is not depressed sometimes.In the reciprocal operation of rolling, utilize the first thick universal rolling machine 2 to depress the thickness of web front end and to have eliminated thickness of slab poor, even therefore also no problem by the second thick universal rolling machine generation thickness of slab difference.Though worry back and forth producing harmful blemish such as sandwiching defective in the boundary portion of thickness of slab difference in the operation of rolling,, in the reduction ratio of web thickness is scope below 30%, do not produce blemish according to the inventor's research.Wherein, become under the situation of the last roll mill that rolls in the end at the second thick universal rolling machine, the web reduction ratio on the smart universal rolling machine 5 of subsequent processing is little, so also consider to change operation according to the step that produces on the second thick universal rolling machine.That is, big to the situation of the indelible degree of finish rolling of being undertaken under in this thickness of slab difference by smart universal rolling machine 5, oppositely carry and be rolled part H, utilize the first thick universal rolling machine 2 to be rolled once more, depress whole of short transverse of web and elimination gets final product.On the other hand, under the situation of the degree that this thickness of slab extent can be eliminated for the finish rolling of being undertaken by finishing mill 5, roll operation in the end, beginning finish rolling operation gets final product.Also can in roll mill opening that the last pass of operation makes the second thick universal rolling machine 4 greater than the size that is rolled part H, rolling and make and be rolled part H and pass through, in this case, it is not poor not produce thickness of slab near the web front end.

In addition, in roll in the operation, preferably be rolled the cross section view of part observing from rolling direction, the angle of the crossing α between the edge of a wing and the web forms 95＜α≤110 °, more preferably forms 95＜α≤100 °.By forming this angle of the crossing, horizontal roll separates after rolling apace with the edge of a wing inner face that is rolled, and prevents to produce defective on the inner surface of the edge of a wing.In addition, the roll amount of shortening and improve a piece of writing in the time of can reducing roll wear, thus prolong roll campaign.Form at angle of the crossing α under the situation of 95＜α≤100 ° the edge of a wing and web, on thick

universal rolling machine

2,4, the side of depressing edge of a wing side that makes horizontal roll 21,41 with the angled θ of vertical: the mode of 5＜θ≤10 ° tilts.

The invention is not restricted to configuration shown in Figure 1, if having the first thick omnipotent calender 2, edging mill 3 and second thick universal rolling machine 4 each equipment more than one, then the configuration to other any ways can both be suitable for.For example, can be more than two with any the continuous configuration at least in the first thick universal rolling machine, edging mill, the second thick universal rolling machine.In addition, also can change the configuration sequence of the first thick universal rolling machine, edging mill, the second thick universal rolling machine, for example in roll operation begin to dispose edging mill, the second thick universal rolling machine most.And it is rolling, direct by (be not rolled and pass through roll mill) that each roll mill can reverse usually, therefore also can make rolling order inconsistent with the order of roll mill.

In to roll T-steel that operation obtains rolling by the finish rolling operation be finished size.The schematic diagram of the structure that smart universal rolling machine is described has been shown among Figure 10.Smart universal rolling machine 5 has at the horizontal roll 51a, the 51b that rotate on the trunnion axis and the perpendicular roll 52a, the 52b that rotate on vertical axis, the side of

horizontal roll

51a, 51b and roll outer peripheral face quadrature.

In the finish rolling operation, will rolling the angle of the crossing α that makes the edge of a wing and web in the operation in last operation, to form the angle of the crossing that rolled parts greater than 90 ° angle is configured as the edge of a wing and web be 90 °.When utilizing the rolling edge of a wing that is rolled part H of the smooth perpendicular roll 52a of periphery, the edge of a wing is shaped as vertical with web.The reduction in thickness on the edge of a wing is a few percent, even big also preferred gently depressing below 5%.At this moment, by make perpendicular roll 52b press on

horizontal roll

51a, 51b not with the side of a side in opposite directions, the edge of a wing,

horizontal roll

51a, 51b are moved vertically.

In smart universal rolling machine, web almost is not depressed, and perhaps, is gently depressed with the reduction in thickness of a few percent according to the degree of adjusting shape, size.Especially, by the second thick universal rolling machine 4 carry out rolling, produce in the part of being depressed by

horizontal roll

41a, 41b and near the part that is not depressed (the web leading section 11a) under the situation of thickness of slab difference, it is poor to eliminate this thickness of slab gently to depress web.In order to reach this purpose, the width of the face of depressing that makes

horizontal roll

51a, 51b is greater than web inside dimensions (thereby greater than W2).Preferably, form web 11 inside dimensions about 105～150%.

If use above manufacture method of the present invention and rolling equipment group, then can make the identical and T-steel of a plurality of sizes that edge of a wing thickness is different of inside dimensions.The T-steel that inside dimensions is constant, shown in Figure 13 (a), even edge of a wing thickness t f changes, web inside dimensions Ai is also constant.In the present invention, the aperture between the side of a perpendicular roll 42a by adjusting the second thick universal rolling machine and the side of

horizontal roll

41a, 41b can be adjusted the thickness of slab tf on the edge of a wing.At this moment, move vertically, be configured to make the side face c of perpendicular roll 42b to contact with the side b of the opposite side of

horizontal roll

41a, 41b in order not make horizontal roll 41a, 41b.At this because the width of the roll outer peripheral face of

horizontal roll

41a, 41b equates with the web inside dimensions, so can with edge of a wing thickness irrespectively with web inside dimensions Ai rolling be constant size, can easily make the constant T-steel of inside dimensions.

[embodiment]

[first embodiment]

Use rolling equipment shown in Figure 1, by the steel ingot in the rectangle cross section with thickness 250mm, width 310mm, rolling is the T-steel of target size with web height 300mm, flange width 100mm, web thickness 9mm, edge of a wing thickness 16mm.

The first thick universal rolling machine 2 uses the roll mill of the structure shown in Fig. 2 (a).The width W 1 of the face of depressing of horizontal roll forms 320mm and greater than the target inside dimensions L of web (for 283mm), the side of horizontal roll and vertical angulation θ are 7 °.About perpendicular roll configuration become in opposite directions, cross sectional shape the width center with roll crown of forming is the summit and has from the tilted laterally zygomorphic chevron shape of hypotenuse of 7 ° of angles of vertical.In addition, about perpendicular roll in the perpendicular roll pushed of the side to horizontal roll adjust pressing force, make and can not move along horizontal axis because of the rolling horizontal roll that makes to the edge of a wing.

Edging mill 3 uses the edging mill of structure shown in Figure 3.The large-diameter portion of edger roll and the step of minor diameter part are 44mm, and the roll width of guaranteeing large-diameter portion is more than the 500mm, and the roll width of minor diameter part is more than the 200mm.In addition, the inclination angle of step part is with vertical angled 7 °.

The second thick universal rolling machine 4 uses the roll mill of structure shown in Figure 4.The roll mandrel of horizontal roll is not reinforced especially, used common structure.The width W 2 of the face of depressing of horizontal roll is 283mm, with in the web target inside dimensions of rolling in the operation equate that the side of the rolling edge of a wing one side of horizontal roll is from tilted 7 ° of angles of vertical.In addition, the size of the Machining of Curved Surface of horizontal roll bight a forms circular-arc (the web end side A/F d of horizontal roll is the web thickness+about 60mm that is rolled part) of radius 30mm.In addition, about perpendicular roll in the perpendicular roll of the side that the edge of a wing is rolled, its cross sectional shape width center with roll crown of forming is the summit and has from the vertical angle of inclination the laterally zygomorphic chevron shape of 7 ° hypotenuse that the perpendicular roll of depressing the opposite side of web leading section along short transverse forms the smooth cylinder type of roll crown.

Smart universal rolling machine 5 uses the roll mill of structure shown in Figure 10.The width of horizontal roll is 320mm.

Begin most, utilize the rolling described steel ingot of thick moulding roll mill 1 (the double formula roll mill of concave roll has been assembled in use), form the roughly T-steel base of T section shape.The web thickness of the T-steel base that is obtained is 40mm, and edge of a wing thickness is 75mm, and web height is 365mm, and flange width is 130mm.Then, utilize, carry out the back and forth rolling of 5 passes, depress the web and the edge of a wing the approaching in order rolling unit that is configured to of the first above-mentioned thick universal rolling machine 2, edging mill 3 and the second thick universal rolling machine 4.Roll the pass schedule of operation in table 1, having illustrated.

[table 1]

Table 1

(mm)

Annotate 1:U1: the first thick universal rolling machine

Annotate 2:E: edging mill

Annotate 3:U2: the second thick universal rolling machine

In the second thick universal rolling machine 4, use perpendicular roll to depress the web leading section along the web height direction, web height is adjusted.At this moment, the perpendicular roll of depressing the web front end forms the state with the horizontal roll contacts side surfaces, on one side the axial load of support level roll be rolled on one side.At last, utilize smart universal rolling machine 5 with horizontal roll and perpendicular roll, the edge of a wing applied gently depress on one side be rolled and the inclination on the edge of a wing be shaped as vertical on one side.Gently depress web portion.Measuring web height, flange width, web thickness, the edge of a wing thickness of resulting T-steel after the hot rolling, is the size with congruence, has confirmed can satisfy by hot rolling manufacturing according to the present invention the T-steel of target size.Especially, the rolling web height that is difficult to adjust by in the past can carry out hot rolling in the scope of desired value ± 1mm, and end surface shape is also good.

Further, use identical rolling equipment, identical and edge of a wing thickness is the inboard constant T-steel of 19mm when making inside dimensions and being 16mm with edge of a wing thickness.T-steel base after using thick moulding roll mill 1 pair cross-section size identical blank steel billet being rolled during as 16mm with edge of a wing thickness is of a size of web thickness 33mm, edge of a wing thickness 75mm, web height 365mm, flange width 123mm.Then, utilization according to the rolling unit that the approaching configuration of this order forms, is carried out the back and forth rolling of 5 passes with the first thick universal rolling machine 2, edging mill 3 and the second thick universal rolling machine 4, depresses the web and the edge of a wing.Roll the pass schedule of operation in having illustrated in the table 2.

[table 2]

Table 2

(mm)

Annotate 1:U1: the first thick universal rolling machine

Annotate 2:E: edging mill

Annotate 3:U2: the second thick universal rolling machine

In the second thick universal rolling machine 4, use perpendicular roll to depress the web leading section along the web height direction, web height is adjusted.At this moment, the perpendicular roll of depressing the web front end is identical when being 16mm with edge of a wing thickness, forms the state with the horizontal roll contacts side surfaces, on one side the axial load of support level roll be rolled on one side.At last, utilize smart universal rolling machine 5, the edge of a wing is applied gently depress and be rolled, the inclination on the edge of a wing is shaped as vertical with horizontal roll and perpendicular roll.Gently depress web portion.Obtained that the each several part after the hot rolling is of a size of web height 303mm, flange width 100mm, web thickness 9mm, the edge of a wing is thickness 19mm and the finished product of size congruence.The web inside dimensions is 284mm, is to be the identical value of finished product of 16mm with edge of a wing thickness.

On the other hand, as a comparative example, use and to set to such an extent that the rolling equipment in the past (Figure 14) that constitutes greater than the thick universal rolling machine of web width, edging mill rolls operation in implementing, make T-steel by a face width degree of depressing with horizontal roll.Steel ingot size, the T-steel each several part target size after hot rolling is identical when being 19mm with the edge of a wing thickness of example of the present invention.Roll the pass schedule of operation in having illustrated in the table 3.Have only a thick universal rolling machine in the equipment of comparative example, be the back and forth rolling of 9 passes so carry out the pass number, rolling up to target size.

[table 3]

Table 3

(mm)

Annotate 1:U: the first thick universal rolling machine

Annotate 2:E: edging mill

In comparative example,,, produced size and departed from so web height greater than the 300mm of target, forms about 306mm because can not depress the front end of web.Therefore, need to cut off the end of web after rolling, need spended time and expense, manufacturing cost increases.In addition because the pass number increases, so compare with embodiments of the invention, in the rolling time that rolls increase to about 2 times, productivity ratio significantly reduces.

In addition, in the foregoing description of the arrangement of having used table 1 and table 2, attempting the width of the horizontal roll of W1 and smart universal rolling machine is changed to 340mm respectively, but the result is still good.And, in the above-described embodiments, the chamfer machining (Fig. 5) of the shape of the bight a of the horizontal roll of the second thick universal rolling machine 4 being carried out C20 (d=web thickness+40mm) and to it in that (d=web thickness+30mm) replaces circular-arc (Fig. 4) of radius 30mm and under the situation about being rolled, the result is also still good from the bight of horizontal roll to carrying out step processing (Fig. 6) the width 50mm.

[embodiment 2]

Below as the second embodiment of the present invention, use rolling equipment shown in Figure 1 rolling with web height 500mm, flange width 150mm, web thickness 12mm, edge of a wing thickness 22mm T-steel as target size from the steel ingot in rectangle cross section with thickness 300mm, width 620mm.

The first thick universal rolling machine 2 uses the roll mill of the structure shown in Fig. 2 (b).The width W 1 of the face of depressing of horizontal roll for 530mm greater than the web inside dimensions, the side of horizontal roll and vertical angulation θ are 7 °.About perpendicular roll configuration become in opposite directions, the width center with roll crown of forming on cross sectional shape is the summit and has from the vertical angle of inclination the laterally zygomorphic chevron shape of 7 ° hypotenuse.In addition, about perpendicular roll in the perpendicular roll of the side of pushing horizontal roll adjust pressing force, make that horizontal roll can be because of not moving up at trunnion axis to the rolling of the edge of a wing.

Edging mill 3 uses the edging mill of structure shown in Figure 3.The large-diameter portion and the step between the minor diameter part of edger roll are 67mm, and the roll width of guaranteeing large-diameter portion is more than the 550mm, and the roll width of minor diameter part is more than the 200mm.In addition, the inclination angle of step part and vertical are angled 7 °.

The second thick universal rolling machine 4 uses the roll mill of structure shown in Figure 4.The width W 2 of the face of depressing of horizontal roll for 477mm with in the web target inside dimensions of rolling in the operation equate 7 ° of the sides of horizontal roll of depressing the edge of a wing from the vertical angle of inclination.In addition, the size of the Machining of Curved Surface of horizontal roll bight a is circular-arc (the d=web thickness+60mm) of radius 30mm.In addition, about perpendicular roll in the perpendicular roll of a side on the rolling edge of a wing, the width center with roll crown of forming on cross sectional shape is the summit and has from the vertical angle of inclination the laterally zygomorphic chevron shape of 7 ° hypotenuse that the perpendicular roll of depressing the opposite side of web leading section on short transverse forms the smooth cylinder type of roll crown.

Smart universal rolling machine 5 uses the roll mill of structure shown in Figure 10.The width of horizontal roll is 520mm.

At first, use thick moulding roll mill 1 that described Rolling from Ingot is made the roughly T-steel base of T section shape.The web thickness of the T-steel base that is obtained is 50mm, and edge of a wing thickness is 95mm, and web height is 585mm, and flange width is 185mm.Then, utilize the first above-mentioned thick universal rolling machine 2, edging mill 3, the second thick universal rolling machine 4 near the rolling unit that configuration forms, are carried out the back and forth rolling of 5 passes according to this order, depress the web and the edge of a wing.Roll the pass schedule of operation in table 4, having illustrated.

[table 4]

Table 4

(mm)

Annotate 1:U1: the first thick universal rolling machine

Annotate 2:E: edging mill

Annotate 3:U2: the second thick universal rolling machine

Utilize the second thick universal rolling machine 4 so that the perpendicular roll of web front is rolled by the state that is pressed in the horizontal roll side, depress the web leading section, web height is adjusted along the web height direction.At last, utilize smart universal rolling machine 5, the inclination on the edge of a wing is shaped as vertical with horizontal roll and perpendicular roll.Measure web height, flange width, web thickness, the edge of a wing thickness of the T-steel that is obtained after the hot rolling, the size of formation and congruence, web height is in the scope of desired value ± 1mm, and end surface shape is also good.

As a comparative example, use in the rolling equipment enforcement in the past that constitutes by the first universal rolling machine (a) shown in Figure 16, edging mill and the second universal rolling machine (b) and roll operation, make the T-steel of same size.Roll the pass schedule of operation in table 5, having illustrated.In the equipment of this comparative example, because can not use the second universal rolling machine to depress the thickness on the web and the edge of a wing, so carry out the reciprocal rolling target size that is rolled down to that the pass number is 9 passes.Therefore, compare with embodiments of the invention, in the rolling time that rolls be increased to about 2 times, productivity ratio significantly worsens.Finished size and congruence do not have special problem.

[table 5]

Table 5

(mm)

Annotate 1:U1: the first thick universal rolling machine

Annotate 2:U2: the second thick universal rolling machine

Can confirm according to above result, manufacture method and rolling equipment by T-steel of the present invention, even large-sized T-steel that web height 500mm, flange width 150mm are such, also can be by the good T-steel of hot rolling manufacturing dimension precision, and compared with the past, significantly improved rolling efficiency.

Industrial applicibility

Manufacture method and rolling equipment group according to T-steel of the present invention, can obtain just can make the shape of web leading section good and can obtain accurately effective manufacture method and the rolling equipment group of the T-steel of the web height expected by hot rolling, industrial extremely useful.

Label declaration

1 thick moulding roll mill

2 first thick universal rolling machines

3 edging mills

4 second thick universal rolling machines

5 smart universal rolling machines

10 T-steels

11 webs

11a end face (web)

12 edges of a wing

12a end face (edge of a wing)

15 enations

21a, 21b horizontal roll

22a, 22b erect roll

31a, 31b edger roll

32 minor diameter parts

32a depresses face

33 large-diameter portions

41a, 41b horizontal roll

42a, 42b erect roll

51a, 51b horizontal roll

52a, 52b erect roll

The width of the outer peripheral face of the horizontal roll of the W1 first thick universal rolling machine

The width of the outer peripheral face of the horizontal roll of the W2 second thick universal rolling machine

The target inside dimensions of L web

H is rolled part (T-steel base)

The a bight

The b side

The c side face

The d A/F

The inside dimensions of Ai, Ai1, Ai2, Ai3 web

The side dimension of Ao, Ao1, Ao2, Ao3 web

Tf1, tf2, tf3 edge of a wing thickness

Claims

1. the manufacture method of a T-steel comprises: in roll operation, be that the web and the edge of a wing of the T-steel base of T shape shape is rolled to dumming; And the finish rolling operation, carry out it is characterized in that with form the finish rolling of finished form by the T-steel base that rolls the operation acquisition in described,

Rolling operation in described comprises:

The rolling process that is undertaken by the first thick universal rolling machine, in the described first thick universal rolling machine, horizontal roll is up and down depressed whole of top and bottom on the thickness of slab direction of web;

The flanging operation is depressed the end face on the edge of a wing; And

The rolling process that is undertaken by the second thick universal rolling machine, in the described second thick universal rolling machine, use the width of roll outer peripheral face and bight web leading section side identical with target web inside dimensions be processed to not rolling web face shape about horizontal roll, depress web near leading section the top and bottom of thickness of slab direction, and about perpendicular roll in the perpendicular roll of a side depress the edge of a wing along the thickness of slab direction on the edge of a wing, the perpendicular roll of opposite side makes outer peripheral face contact with up and down horizontal roll and depresses the end face of web along the short transverse of web.

2. the manufacture method of T-steel as claimed in claim 1 is characterized in that,

In the rolling process that is undertaken by the described second thick universal rolling machine, the outer peripheral face of the perpendicular roll of depressing the web end face is contacted with up and down horizontal roll and adjust aperture between the perpendicular roll of opposite side and the horizontal roll side up and down, make the constant and T-steel of a plurality of sizes that edge of a wing thickness is different of web inside dimensions thus.

3. the rolling equipment group of a T-steel, the T-steel base that with the dumming is T shape shape is as being rolled part, and rolling this is rolled the web and the edge of a wing of part, it is characterized in that, disposes:

The first thick universal rolling machine, the width with roll outer peripheral face is greater than the described horizontal roll up and down that is rolled the target web inside dimensions of part;

Edging mill is depressed the described end face that is rolled the edge of a wing of part; And

The second thick universal rolling machine, have up and down horizontal roll and about perpendicular roll, in the described horizontal roll up and down, the width of roll outer peripheral face is identical with the described target web inside dimensions that is rolled part, and the bight of web front is processed to the shape of not rolling web face, in the perpendicular roll about described, the perpendicular roll of one side is depressed this edge of a wing along the thickness of slab direction on the edge of a wing, and the perpendicular roll of opposite side makes the outer peripheral face of this perpendicular roll contact with up and down horizontal roll and depresses the end face of web along the short transverse of web.