JPS59137101A - Rolling method of h-beam - Google Patents

Abstract

PURPOSE:To eliminate the joint defect of a sectional sleeve and to enlarge the freedom of the sleeve by applying a specific magnification ratio larger than the draft of a web part to the draft of a flange part in a universal rolling of an H-beam provided with sectional sleeves. CONSTITUTION:An H-beam is formed by rolling with a roughing mill 1, a roughing universal mill 2(UR mill), an edging mill 3, and a finishing universal mill 4 (UF mill). Both of UR mill 2 and UF mill 4 have sectional sleeve type rolls 5 each of which is constituted of sectional sleeves 6, 7 and a spacer 8 having diameter smaller than those of the sleeves 6, 7. Further, the draft of a flange part 9 is made to about 1.2-2.0 times the draft of a web part 10. By the elongations in the width and longitudinal directions of the flange part 9, the web part 10 is pulled to flatten a projecting part 11. In this way, the defect of a joining part is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling H-section steel using split sleeve type rolls as horizontal rolls of a universal mill.

<Prior art> Universal rolling of H-beam steel requires horizontal rolls with different roll widths for each series, and the number of rolls required is large because the worn parts of the side walls must be ground and reused. Become. For this reason, various horizontal rolls have been proposed in which the sleeve to be fitted onto the arm is divided into a plurality of parts in the axial direction, and the divided sleeves are integrated using various methods so that the width can be adjusted.

A problem with such a split sleeve type roll is the joint between the divided sleeves or the joint between the sleeve and the spacer. In other words, it is a contact between rigid bodies, and it is possible to eliminate the gap by finishing the contact surfaces, but it is difficult to completely eliminate the gap because sleeves need compatibility and are subject to wear. spreads due to the rolling load, and thorn-like protrusions are generated in the rolled part of the web. When a web having such protrusions is rolled, a lap eave is formed. Such a lap eave has a serious defect and cannot be used as a product.

As a method to prevent such defects, there is a method (1982) in which the protrusions caused by the joints of 12-sleeve horizontal rolls are made into smooth protrusions, and then only the protrusions are removed during edge rolling. Patent application No. 21
No. 48710: Method of rolling section steel and its rolling mill row),
(11) The outer diameter of the spacer for adjusting the roll width arranged between the sleeves in the horizontal rolls of the finishing rolling mill is made smaller than the outer diameter of the sleeve, and the web portion corresponding to the spacer is finished rolled in the rough rolling mill of the previous stage. There is a method in which this part is not rolled down at all in the finish rolling mill (Japanese Unexamined Patent Publication No. 57-150702, rolling method for double-barrel steel), but in any of these methods, the split sleeve type A rolling process is required either before or after a universal rolling mill using horizontal rolls to eliminate the bulge at the joint.

Furthermore, in case (I), the edger roll needs to have a special shape, and in case (11), the horizontal roll of the roughing mill is not a split type but an integrated roll. Incidentally, the roll body needs to have a special shape in which the center bulges out.

<Object of the Invention> This invention was proposed in view of the above circumstances, and its purpose is to obtain a smooth web surface using a normal split sleeve type horizontal roll without performing special correction rolling. The object of the present invention is to provide a method for rolling H-section steel that allows for rolling of H-beam steel.

<Structure of the Invention> The method for rolling an H-beam steel according to the present invention is such that when performing universal rolling using ordinary split sleeve type rolls as horizontal rolls, the flange part rolling reduction is 1 of the web part rolling ratio.
．． Universal rolling is performed so that the thickness is 2 times or more, preferably 2.0 times or less. Note that it is preferable that all passes except the empty pass be rolled under the above conditions.

<Example> The present invention will be described below based on illustrated embodiments.

What is shown in Figure 1 is the pass line for H-beam steel, including a rough rolling mill 1 and a rough universal rolling mill (hereinafter referred to as UR mill).
2, an edger mill 3, and a finishing universal rolling mill (hereinafter referred to as UF mill) 4.

The horizontal rolls of the UR mill 2 and the UF mill 4 are conventional split-sleeve rolls 5, with a split sleeve 6.7 and an outer diameter smaller than that of this sleeve, as shown in FIG. It consists of a spacer 8 for adjusting the roll width.

In universal rolling with such a configuration, the flange part 9 rolling car is set to ψf=in (tr 2 /1f1), and the web part 10 rolling reduction rate is set to ψ, = Jn (tvz 71
w1), 162≦ψf/ψ1≦2.0 However, the flange portion 9 is rolled down more strongly than the web portion 10 so that tl: plate thickness before rolling t2: plate thickness after rolling.

The conventional reduction ratio ψf/9'v is about 0.9 to 1.1,
Normally, a UF mill or the like aims for 1.0, but when rolling down using the split sleeve type roll 5 at such a rolling reduction ratio, a bulge 11 is generated in the center of the web portion as shown in Fig. 2. become. On the other hand, in the present invention,
Since the flange portion 9 is strongly compressed, the flange portion 9 extends in the width direction and the length direction, and accordingly, the web portion 10
is pulled and thinned, resulting in a flat web surface.

Here, in the split sleeve type roll 5, it is sufficient that the roll side surface contacts the entire inner surface of the flange, as well as the inner corner portion between the flange and the web and two-thirds or more of the web surface. Theoretically, it is sufficient for the roll 5 to roll only the inner surface of the flange and the inner corner, but if the web thinning is performed only by tension, variations in the thickness of the web will occur, so rolls of approximately 215 mm or more of the web surface may be used. It is necessary to restrain it by 5.

Furthermore, if the rolling ratio is smaller than 1.2, a bulge will occur, and if it is larger than 2.0, the web will become thinner and the residual stress in the rolled material will increase, which will increase the occurrence of bending during the cooling process, resulting in straightening, etc. Further, the side surfaces of the roll 5 are subject to severe wear, which is not preferable.

Example A beam blank with a web height of 1268 m and a web thickness of 791 m was rolled into a H400 x 400 x 13/21 product using a UR mill for 13 passes and a UP mill for one pass under the rolling conditions shown in the following table. In both cases, pressure was applied using a split sleeve type roll.

As a result of such pressure, the difference in web thickness is tz-(t+-1-13)/2#40μm in FIG. could be distinguished, but the bulge in the center of the web could hardly be seen.

Example UP When rolling the H400X400X13/21 in a mill, the central bulge amount was measured while changing ψf/ψ between 1.0 and 2.0. Figure 4 is a graph showing the results, and although it varies depending on the application, the central bulge amount is 0.
If it is 7% or less (ψf/ψv is 1.2 or more), it is sufficiently practical and there is no problem in terms of appearance such as painting. 0.4
% or less (ψ, /ψ, is 1.4 or more), it can be used for the same purposes as those rolled with integral rolls.

Furthermore, if ψf/ψ is larger than 2.0, the residual stress after cooling becomes large, which may cause problems such as bending during cutting.

Furthermore, the UR mill has an edger mill at the rear stage, and in combination with this edger mill, the patent application No. 56-214
Since methods such as 840 can also be used in combination, the method of the present invention exhibits extremely excellent effects particularly in UF mill rolling.

<Effects of the Invention> As described above, according to the present invention, a smooth web surface can be easily obtained using a normal split sleeve type horizontal roll without performing special correction rolling, and it is extremely economical. Furthermore, the degree of freedom of split sleeves is increased, and (1) the usage limit of the sleeve is expanded, (11) rolling is possible even if the spacer positions of the upper and lower horizontal rolls do not match, and corner processing on the spacer side of the 010 sleeve is possible. No longer needed. +IV) If the radii of the inner corners of the web and flange match, it becomes possible to roll multiple sizes with the same roll by replacing the spacer.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the pass line of the H-beam steel, Fig. 2 is a schematic diagram showing the universal mill used in this invention, Fig. 3 is a schematic diagram showing the H-beam steel after rolling, and Fig. 4 is a schematic diagram showing the H-shape steel after rolling. It is a graph showing the relationship between the rolling reduction rate and the amount of central bulge. 1. Rough rolling mill, 2. UR mill, 3. Edger mill, 4. UP mill, 5. Split sleeve roll,
6, 7...Divided sleeve, 8.φ spacer, 9. flange portion, 1o.φ unib portion, 11..bulging portion. Figure 1 Figure 2 Figure 3 Figure 6 ff1l base (% spear)

Claims (1)

[Claims] (1) A method for rolling an H-section steel, which comprises universal rolling of an H-section steel using split-sleeve type rolls as horizontal rolls, the rolling reduction of the flange portion being 1.2 times or more the reduction ratio of the web portion.