Metal deforming – By use of roller or roller-like tool-element – Included in roller-cluster
Patent
1994-09-21
1996-09-10
Bray, W. Donald
Metal deforming
By use of roller or roller-like tool-element
Included in roller-cluster
72 89, 72 16, B21B 108, B21B 3712
Patent
active
055534759
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an H-shaped steel having a good dimensional accuracy by hot rolling employing a universal rolling mill.
BACKGROUND ART
Facilities for hot rolling an H-shaped steel comprise a breakdown rolling mill 1, a universal rough rolling mill 2, an edger rolling mill 3, and a universal finish rolling mill 4 as shown in FIGS. 1(a) and 1(b). In the facilities, raw materials such as slab 5, bloom 6, or beam blank 7 shown in FIG. 2 are successively rolled by the above-described mills to form an H-shaped steel having a predetermined sectional dimension.
In the above-mentioned facilities, the breakdown rolling mill 1 is a two high mill having upper and lower rollers provided with, along a roller barrel, a plurality of open passes 8 or closed passes 9 shown in FIG. 3. In this mill, there is formed a roughly H-shaped billet.
In the universal rough rolling mill having horizontal rollers and vertical rollers, the web w of the billet is reduced by the horizontal rollers 10a and 10b in the thickness-wise direction, and the flanges f of the billet are reduced by the horizontal rollers 10a and 10b, and the vertical rollers 11a and 11b in the thickness-wise direction, respectively as shown in FIG. 4(a). With respect to the widths of flanges, they are reduced by the rolling mill having edger rollers 12a and 12b as shown in FIG. 4(b).
At this stage, the billet obtained by the breakdown rolling is usually rolled over a plural times, and then, it is finished as a final product by the universal finish rolling mill as shown in FIG. 4(c).
In a rolling of the H-shaped steel conducted in a procedure such as above, there is used a rolling mill having horizontal rollers functioning as an upper roller and a lower roller constituting a pair, and vertical rollers functioning as a right roller and a left roller constituting a pair. When a rolling of a material is conducted, a rolling reaction is exerted to each one of the rollers, thereby elastically deforming them. As a result, clearances between the rollers become larger during the operation when compared with the clearances with no load. When the web and flanges are reduced at an usual draft, the thickness of each part after rolling is equal to the dimension of the clearance between the rollers which have rolled the part. Accordingly, if the clearance between the rollers during the rolling is at an inappropriate value, there may be a case where the thickness after the pass differs from an aimed value. Particularly, since there are conducted plural passes of rolling in the usual universal rough rolling, the dimensional fluctuation in a certain pass results in an external disturbance to the-next pass, which functions as a factor inviting the degraded dimensional accuracy of the final product.
Furthermore, demands for thin H-shaped steel have been increasing in the recent years. In the production of these thin H-shaped steels, flange portions which have a cooling rate smaller than that of the web portion are sometimes forcibly cooled by water in the process of hot rolling or after the completion of the final product from the viewpoint of reducing the residual stress or of preventing shape defects. In this occasion, if the thicknesses of the flanges in right and left upper and lower parts are uneven, the temperature of each parts of the steel cannot be uniform. This unevenness of cooling may give rise to shape defects in the resulting product.
Various methods have been studied with respect to a control of clearance between the rollers in the course of rolling. As a typical method, there is so-called set up control. In this method, it is intended to adjust the clearance between the rollers beforehand, namely when no load is applied thereto, by estimating the rolling reaction (rolling load) by means of the linear relationship between the rolling reaction and the increment of clearance between the rollers. As documents regarding this respect, it can be referred to JP-A-63-104714 and JP-A-63-123510, which respectiv
REFERENCES:
patent: 4512169 (1985-04-01), Miura
patent: 4958509 (1990-09-01), Kusaba et al.
patent: 5009094 (1991-04-01), Hayashi et al.
patent: 5203193 (1993-04-01), Iguchi et al.
Hayashi Hiroyuki
Iguchi Takaaki
Inamura Shinji
Bray W. Donald
Kawasaki Steel Corporation
LandOfFree
Method for detecting setting errors of clearance between rollers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for detecting setting errors of clearance between rollers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for detecting setting errors of clearance between rollers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1311924