JPS5837042B2 - Manufacturing method of shaped steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling H-shaped steel or ■-shaped steel by hot rolling.

As is well known, in general, in order to manufacture H-shaped steel and ■-shaped steel by the rolling method, a square steel ingot is bloomed into a square or rectangular cross-section bloom, slab, or rough-shaped steel billet, and then rough and finish rolling is performed. In addition, methods for directly casting blooms, slabs, or rough-shaped steel pieces by continuous casting have also come to be adopted.

By the way, recently there has been an increase in demand for H-beam steel with a wide flange width and a large cross-sectional area, and the process of turning the steel into a rough shape, cooling it, and cleaning cold defects involves an extremely large thermal loss. Since a method of hot rolling all the way through to the product has been adopted, the following problems have arisen in the well-known method for producing rough-shaped steel billets.

(1) As shown in Fig. 1, the well-known production method by blooming rolling mainly performs web rolling of a rectangular steel ingot 1 with a horizontal mill consisting of an upper roll 2 and a lower roll 3. Rolling is performed as follows, and roll sets 2' to 3', 2 are sequentially rolled in the same manner.
The rough-shaped steel piece d is finished with a thickness of 2 nt to 3'', but as is clear from Fig. 1, in this rolling method there is no elongation in the width direction of the flange. In order to obtain shaped steel pieces (ultimately products), thick steel ingots are required.

Therefore, in order to obtain the rough-shaped steel billet d from the steel ingot 1, the number of passes is increased, and the blooming ability is reduced.

In addition, when producing blooms or slabs with good blooming efficiency in the blooming process and obtaining rough-shaped steel slabs in the rough rolling process, the rectangular steel slab 4 shown in Figure 3A (this may also be a rectangular steel ingot) is used. The width f of the flange-equivalent side surface 5 of the rectangular steel piece (hereinafter simply referred to as a rectangular steel piece) must be larger than the flange width g of the rough-shaped steel piece 6 in Fig. 3A, and the rough shape with a wide flange width To produce billets, thick billets must be heated.

Therefore, not only does the heating time in the heating furnace become longer, but the number of rolling passes also increases, resulting in a significant reduction in rolling efficiency.

(2) As mentioned above, when hot rolling is carried out from a steel ingot to a product without intermediate cooling, especially in the case of existing equipment, the above (1)
In addition to this, the process of forming rough shaped billets takes too much time, which tends to cause an imbalance in capacity between rough and finish rolling in the subsequent process, resulting in a problem that productivity does not improve.

(3) Making rough shaped steel pieces with wide flanges by continuous casting tends to cause mold thermal distortion and casting defects;
Also, problems remain, such as the fact that the flange part is likely to be insufficiently trained.

(4) Furthermore, in relation to the above item (1), in the method of forming a rectangular steel billet by blooming rolling and then making it into a rough shape steel billet in a rough rolling process, the thickness f of the rectangular steel billet 4 in Fig. 3A is compared. Since the web thickness S of the rough-shaped steel billet 8 shown in Figure 3 is small, the stretching of the web to a certain product is extremely large compared to the method in which the rough-shaped steel billet is made into a rough-shaped steel billet by blooming rolling and then rough rolling is performed.

As a result, the crop length increases, resulting in a significant decrease in yield.

The purpose of the present invention is to provide an efficient method for manufacturing a section steel with a high yield without the above-mentioned problems. A plurality of pressing surfaces having different top angles of the central bulge are provided for the roll pair or roll pair group, and then a side surface corresponding to the flange of the rolled material having a square or rectangular cross section is pressed so that the center of the central bulge is the center of the central bulge. After rolling the rolled material in the order of the apex angle to correspond to the axis corresponding to the web center and splitting the flange-compatible side surface, a web pressing bulge consisting of a crest portion and an outwardly inclined portion and the web pressing bulge portion are formed. A pair of rolls having deep grooves on both sides that do not contact the flange of the material to be rolled are used to repeatedly roll down the web portion of the material to be rolled without restraining the flange of the material to be rolled, thereby performing rough rolling while metal flow to the flange. The method of manufacturing a section steel is characterized by rolling the steel and then finishing rolling.

The present invention will be explained in more detail below with reference to the drawings.

Now, if the rough shaped steel piece d obtained in Fig. 1 is an H or I section steel, it will have a caliber h as shown in Fig. 2. i. The pieces are roughly shaped in the order of j by horizontal rolls, and then sent to a finish rolling process (not shown).

The rough-shaped steel pieces obtained in the present invention are similarly processed through a cooling process to remove defects before being manufactured into products, or alternatively, they can be manufactured into products through direct hot roughing and finishing rolling processes without going through the cooling process. It is something that

As mentioned above, there are various problems with the well-known rolling technology in increasing the absolute length of the flange width after the slab is made into a rough shape. The flange widths t and u of the rolled steel pieces 7 and 8 at the time of rolling are the width f of the flange-equivalent side surface 5 of the rectangular steel piece 4 and the rough-shaped steel piece 6,
It is usually smaller than the flange width g.

Therefore, the present inventors have researched a method for obtaining a rough shaped steel piece from the steel piece 4, for example, having a flange width larger in absolute value than the width f of the flange-equivalent side surface 5 of the rectangular steel piece 4, and as a result, the present invention method has been developed. As a result, they succeeded in developing the above-mentioned width f, in other words, it became possible to manufacture a section steel with a wide flange from a rolled material consisting of a thin rectangular or rectangular cross-section steel ingot or slab. It is something.

For convenience of explanation of the present invention, the names of each part of the rolled material are defined as shown in FIGS. 4 and 5.

In FIGS. 4 and 5, the X axis passing through the center of the rolled materials 9, 9' is called the web center corresponding axis, and the Y axis perpendicular to this is called the central axis.

Both side surfaces 10 and 10' parallel to the Y-axis are referred to as flange-equivalent side surfaces, and both side surfaces 11 and 11' parallel to the X-axis are referred to as web-equivalent side surfaces.

Now, the material to be rolled 9 is rolled by a pair of rolls 12. shown in FIG.
1 2', but the roll pair 1 2 . 1
2' is the central bulging part 13.13', the central bulging part 1 3
．． Grooves 14 provided symmetrically around 1 3'
, 15, 14', and 15', and during rolling, the roll axis 16. Axis 1 perpendicular to 1 6'
7.17' is made to coincide with the X-axis.

For convenience of explanation, FIG. 6 shows roll pair 1 2 . 1 2' are shown separated, but both rolls 1 2 . 1 2
The roll pair 12.12' that simultaneously rolls and rolls the material 9 to be rolled may be a vertical roll or a horizontal roll.

Next, the details of the rolling procedure are shown in FIG. The central bulge 13.13 is aligned with the axis X corresponding to the web center of the material 9 to be rolled at 1 2'.
When the flange-equivalent side surfaces are pressed while aligning their centers, the flange-equivalent side surfaces are spread out as shown in FIG. 7A, filling the grooves 14, 15, 14', and 15'.

In this case, the central bulge 1 3 . As shown in the figure, the longitudinal section parallel to the roll axis of 1 3' is an isosceles angle with slightly rounded apex and sides, and if the apex angle, that is, the apex angle, is 2α, then the initial pressure Therefore, it is better to be small, and then to increase as the pass progresses in the order of A and C in Figure 7.

That is, if the rolled material 9 is pressed in the order of increasing apex angles such as 2α, 2β, and 2γ, the side surface corresponding to the flange can be pushed down and expanded without difficulty.

In this case, the grooves are, for example, 15a and 15b in Fig. 7A and C.
It changes like this.

The shapes and dimensions of the central bulge and groove according to the present invention are not limited to those described above, and can be designed within the scope of the present invention.

For example, the shape of the central ampullae is semicircular when expressed in cross section.
It is possible to use the same type or a combination of suitable shapes such as a trapezoid, an equilateral triangle, and a rectangle, as long as they have rounded corners necessary for rolling.

The same goes for grooves, which should be designed according to the intended steel section.

Therefore, such suppression surfaces may be provided in the same role,
The roles may be different.

In the present invention, a group of roll pairs is used to refer to the case where a plurality of pairs of rolls with different pressing surfaces are used, and the type and number of pressing surfaces are preferably designed according to the product type, rolling, and quality conditions.

Now, the side surface 1 corresponding to the web of the rolled object 9 which has gone through the process shown in Fig. 7 C.
1. 11' is further shown in FIG. 8 as a pair of rolls 23.23
'To be rolled by.

The pair of rolls 23, 23' are formed symmetrically with respect to the central axis Y, and have a flat top part 24, 24' parallel to the axis X corresponding to the web center, and an outer inclined part 25, 25'. It consists of a projecting portion 26.26' and a deep groove portion 27.27'.

The purpose of using a pair of rolls having such a shape is to generate a positive metal flow toward the flange-equivalent side surface 10.10' of the rolled material 9 by the outwardly inclined portions 25.25' of the web pressing bulges 26, 26' during rolling. In order to enhance this effect, the present inventors have found the following requirements for the roll shape as a result of experiments.

However, U: Length of the bottom of the web pressing bulge Uo = Product web internal method (see Figure 9) U1: Breakdown finish web internal method S: Flat top length In Figure 8, the rolled material 9 is When finishing the web with thickness t and breakdown finish web internal method U1, the length U of the bottom part of the web pressing bulge is set by U.

The reason for designing the relationship <U1 is to easily guide the rolled material 9 to the next-stage rough universal mill, and to prevent the flange from being rolled down and crushed by the next-stage rough universal mill. In addition, if the top length S is equal to the bottom length U of the web pressing bulge, the structure is the same as the conventional blind hole rolling method, and the rolled part is equal to the bottom length U of the bulge. The web portion of the material 9 is stretched in the length direction, and the side surface 10 corresponding to the flange is extended in the length direction. 1 The metal flow in the 0' direction is reduced.

Furthermore, when the length S of the flat top part is smaller than 1/3 of the length U of the bottom part of the web pressing bulge, the angle of inclination that the surfaces of the externally inclined parts 25, 25' make with the axis X corresponding to the web center becomes small; As a result, excess thickness remains on the side surface of the material to be rolled 9 corresponding to the web, which increases the amount of rolling reduction in the next rough universal mill, which is unfavorable in terms of process balance.

Note that the height h from the bases P, P' of the web pressing bulges 26, 26' to the flat tops 24, 24' is determined by the required web finishing dimension t in the breakdown mill and the bottom length of the web pressing bulges. It is determined by the relationship with SaU.

In addition, the deep groove portions 27 and 27' are flange-equivalent side surfaces 10 and 10.
It may be designed as appropriate as long as the elongation along the web center corresponding axis X and center axis Y direction due to meckle flow in the 'direction is not restricted.

Further, the rolls 23, 23' may be vertical rolls or horizontal rolls, and may be provided on the same roll as the pair of rolls 12, 12' having the central bulge and groove, or may be different rolls. do not have.

Figure 10A shows an example of the structure of a roll for carrying out the method of the present invention, in which a pair of rolls consisting of an upper roll 28 and a lower roll 28' are provided with kat1 to kat4.
The hole forming at3 has a central bulge 13 on the upper roll 28.
, 13a. 13b, the lower roll 28' has central bulges 13', 13a'. Groove 1 on 13b' and each upper and lower roll
5.15a and 15b.

In addition, ka7 4 has flat top portions 24, 24', externally inclined portion 25,
25', deep groove 27.27'.

Figure 10 shows a well-known intermediate universal mill consisting of upper and lower horizontal rolls 29, 29' and left and right vertical rolls 30, 30', and Figure 10 (c) shows upper and lower horizontal rolls 31, 31' and left and right vertical rolls 32, 32'. This is a well-known finishing universal mill consisting of:

With the rolling equipment row configured as above, the web height is 300 mm.
Table 1 shows an example in which an H-beam steel with a flange width of 300 mm, a web thickness of 10 mm, and a flange thickness of 15 mm was rolled.

In the conventional rough rolling method to be compared, a rectangular steel ingot (or billet) 1 shown in FIG. 1 is rolled between a pair of upper and lower rolls 2-3. 2'-
3', 2"-3" *2/// 3 /l/ to form a rough shaped billet d, and then finished in the order of calibers h, i, and j in Figure 2, and then the middle universal at the opening in Figure 10. This is a method of rolling with a finishing universal mill shown in FIG. 10.

As is clear from Table 1, the present invention provides a method for manufacturing sections with wide flanges from thin square or rectangular cross-section steel pieces in an extremely efficient manner and with a high yield, and is extremely useful in practice. It is something.

Therefore, the present invention can be applied to a process consisting of a well-known rolling mill train having a roughing mill followed by a blooming mill, and high efficiency can be obtained immediately.

In other words, it is extremely easy to roll the material to be rolled into a rectangular or rectangular cross-section with a blooming mill, and it is extremely difficult in terms of rolling balance to subsequently apply the method of the present invention to a rough-shaped steel billet with a rough horizontal mill. This is because it is advantageous, and the ability to easily produce rough-shaped steel pieces with different dimensions from the same square or rectangular steel piece is also extremely advantageous in terms of rolling schedules, making it possible to improve productivity.

Furthermore, when a reheating process is adopted, that is, when a rolled material with a rectangular cross section that has undergone a cooling treatment process is used, a thinner material can be used, making reheating easier and improving efficiency.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of a rolling method using the well-known web rolling method, Fig. 2 is an explanatory diagram of the roll force lever after the well-known rough shaped steel billet, and Fig. 3 A, B, C, and D are well-known rolling methods. 4 and 5 are diagrams explaining the names of each part according to the present invention. Figure 6 is a diagram explanatory of rolling procedures according to the present invention. Figure 7 A, B, and C. 8 is an explanatory diagram of the rolling procedure of the side surface corresponding to the flange according to the present invention, FIG. 8 is an explanatory diagram of the rolling procedure according to the present invention, FIG. 9 is a schematic cross-sectional diagram of the H-beam steel, and FIG. 10 is a rolling example of the present invention. FIG. 1... Steel ingot, 2... Upper roll, 3...
...Lower roll, 4...Rectangular steel piece, 5...
... Flange equivalent side surface, 6 ... Rough shaped steel piece, 7
, 8... Rolled steel piece, 9, 9/-... Rolled material, 12, 12'... Roll, 1 3 ,
1 3'... Central bulge, 14, 14', 1
5.15'...Groove, 16. 1 6'・
...Roll axis center, 17, 17'...
...Axis, 1 8. 1 8'...Roll for rolling down the web, 19, 19'...Bulging portion, 20, 20'...Top pressing surface, 21...
...Flange part, 22... Web part, 23.2
3'...roll, 24.24'...curved top,
25, 25'...Outward inclined part, 26, 26', curved/web pressing bulge part, 27, 27'...Deep groove part, 2B, 28'... Roll, 29, 29', 3
1, 31'...Horizontal roll, 30.30',
32.32'...Montachi roll.

Claims (1)

[Claims] 1. For a pair of rolls or a group of roll pairs each having a pressing surface consisting of grooves symmetrical about the central bulge, a plurality of pressing surfaces with different angles at the top of the central bulge are provided, and then a square or rectangular cross-section covering is provided. The flange-equivalent side surface of the rolled material is rolled in the order of the apex angle, with the center of the central bulge aligned with the axis corresponding to the wafer offshore center of the rolled material, and the flange-equivalent side surface is split open, and then the apex and the outer surface are separated. The web portion is repeated without restraining the flange portion of the material to be rolled by a pair of rolls having a web pressing bulge portion consisting of an inclined portion and a deep groove on both sides of the web pressing bulging portion that does not contact the flange of the material to be rolled. A method for manufacturing a section steel, characterized by performing rough rolling while rolling down to allow metal flow to a flange portion, and then performing finish rolling.