Metal fusion bonding – Process – With condition responsive – program – or timing control
Patent
1992-04-02
1994-06-28
Heinrich, Samuel M.
Metal fusion bonding
Process
With condition responsive, program, or timing control
228158, 228170, 228265, 72202, 72203, 219617, 219645, B23K 2004
Patent
active
053239512
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method of joining steel sheet bars inclusive of slab with each other in hot rolling as well as a continuous hot rolling method, and is more particularly to attain a rapid and simple joining operation.
BACKGROUND ART
In the hot rolling of the steel sheet bar, since steel sheet bars inclusive of slabs taken out from a heating furnace hitherto been rolled individually, there were various troubles encountered later at a finish rolling step:
As a countermeasure on the above problems, there is proposed a continuous rolling method wherein a back end portion of a preceding sheet bar is successively joined with a front end portion of a succeeding sheet bar at an entry-side transfer line of a hot finish rolling mill and then subjected to finish rolling, and also there are various methods of joining the sheet bars.
For example, Japanese Patent laid open No. 60-244401 discloses an induction heating pressure welding method using a so-called solenoid type coil S (see FIG. 8), and also Japanese Patent laid open No. 61-159285 discloses an electric heating pressure welding method using an electrode roll.
Furthermore, Japanese Patent laid open No. 61-144203 discloses a joining wherein the front end portion of the succeeding sheet bar is butted to the back end portion of the preceding sheet bar and at least side edge regions in widthwise direction at the butted portion are preliminary joined and rolled at a reduction of not less than 20%.
However, in the methods disclosed in Japanese Patent laid open No. 60-244401 and Japanese Patent laid open No. 61-159285, the full back end face of the preceding sheet bar and the full front end face of the succeeding sheet bar are joining faces and the heating is carried out over a whole area of such joining faces, so that there are caused the following problems: long; and heating equipment is stopped, a long loop is required, while when the heating is carried out during the running of the sheet bar, it si required to take a long running distance and hence the equipment length becomes long.
Furthermore, the method disclosed in Japanese Patent laid open No. 61-144203 has problems that a long time is required for obtaining sufficient joining strength, and the problem of the item iii) is still restrained, and also
SUMMARY OF THE INVENTION
It is an object of the invention to advantageously solve the above problems and to provide a rapid and simple joining method as well as a continuous hot rolling method using such a joining method.
The inventors have made various studies in order to solve these problems and found that in the joining of the sheet bars, it is not always required to join the butted faces of the preceding and succeeding sheet bars over the full area thereof and hence it is enough to join at least both side edge regions at a given ratio.
Furthermore, the inventors have found that when the joint region between the end portions of the preceding and succeeding sheet bars is subjected to a finish rolling, a special means is added at an initial stage of the finish rolling to realize a stronger joining.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of a transfer line at an entrance side of a finish rolling mill including a joining apparatus suitable for carrying out the invention;
FIGS. 2(a)-(g) are plan views of preferable cut shapes at back and front end portions of a preceding sheet bar and a succeeding sheet bar according to the invention;
FIG. 3 is a diagrammatical view of an induction heating apparatus (split type) of transverse system according to the invention;
FIG. 4(a) is a schematic view showing a flow of eddy current induced by the transverse system, and FIG. 4(b) is a graph showing a temperature distribution of a butted region when heating by the same system;
FIG. 5 is a diagrammatic view of an induction heating apparatus (c-shaped) of another transverse system;
FIGS. 6(a) and (b) are schematic views showing a change of end portion shape of sheet bars before and after pushing;
FIG. 7 is a graph showing
REFERENCES:
patent: 4706871 (1987-11-01), Kajiwara et al.
patent: 5121873 (1992-06-01), Sekiya et al.
patent: 5172846 (1992-12-01), Hayashi et al.
Patent Abstracts of Japan, vol. 12, No. 321 (M-736) (3168), Aug. 31, 1988.
Database WPI, Section Ch, Week 7628, Derwent Publications Ltd., London, Great Britain, Class M21, AN 76-52785X(28).
Amagasa Toshiaki
Aoki Fujio
Ebihara Masanori
Hatano Naoki
Ishikawa Takashi
Heinrich Samuel M.
Kawasaki Steel Corporation
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