JPS63215304A - Method for rolling metal stock - Google Patents

Abstract

PURPOSE:To bring the number of roll pressings to be one, to improve the productivity, and to reduce defective parts at ends to improve the yield by pressing only a couple of faces at ends of a metal stock and rolling the stock from the end toward the central part. CONSTITUTION:A continuously cast slab is weighed and cut to form a bloom 14 having a prescribed size and is heated to a prescribed temp. by a soaking pit 12. The bloom 14 is formed so that its lateral section is formed into a rectangular shape and a short edge face of the bloom 14 is put on a transfer table 16 and the bloom 14 is transferred to a blooming mill 18. At a 1st preforming stage, the top and rear end parts of the bloom 14 are pressed by a rolling roll of the blooming mill 18 to form thin thickness parts. Circular recesses 36, 38 are formed on a couple of faces 28, 30 of the pressed bloom 14 facing each other. The bloom 14 is fallen down to lie and is transferred in a push rolling stage; rolling rolls 32, 34 rotate to roll the bloom 14 from the top end or the rear end toward the central part. The top and rear ends 26 are preformed, then the bloom 14 is transferred to the rolling stage and is rolled by a bloom mill 20 or a billet mill 22 to have a prescribed thickness.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for rolling a metal material, such as a steel billet, after ordinary ingot making or continuous casting, and particularly relates to a method for rolling a metal material after ordinary ingot making or continuous casting, and particularly relates to a method for rolling a metal material after ordinary ingot making or continuous casting. , relates to a method of rolling relatively thick metal materials such as slab rolling.

C. Prior Art] For example, when rolling a steel billet into a bloom, the surface of the steel billet extends more than the inside, resulting in a so-called fishtail in which the ends of the billet are unevenly deformed after blooming. This may occur. Since such fuchtails are not suitable for use after rolling, they are usually cut off and removed as a stubble.

For this reason, there is a problem that the production yield of steel slabs is reduced.

However, in order to prevent fishtail and reduce crop loss, prior to blooming, the front and rear ends of the steel billet were pressed with a blooming roll to form thin sections (so-called preforming). Subsequently, methods of blooming the steel billet are known. In this case, the roll press is used to form a rectangular prism shape from the two pairs of surfaces of the steel piece.
It has been carried out once or multiple times. The steel billet after blooming is further rolled into a thinner steel billet in the next step.

[Problems to be Solved by the Invention] However, the roll press requires accurate positioning and presses the front and rear ends of the billet without rotating the rolls of the rolling mill. Because of this, there is a problem that it takes time and the more the number of presses is, the lower the production efficiency becomes. Furthermore, if the press is applied only once, that is, only to one pair of surfaces, fishtails cannot be sufficiently prevented.

The present invention has been made in view of the above circumstances, and aims to provide a method of rolling a metal material that can improve production efficiency and yield.

Means for Solving Problem C: The method of rolling a metal material according to the present invention involves pressing one end of the metal material with a pair of rolling rolls to form a thin part on a pair of opposing surfaces of the metal material. Then, the other pair of surfaces adjacent to the pair of surfaces are preformed by rolling from the ends toward the center, and the metal material is rolled after this preforming. .

[Operation] According to the present invention, only one pair of surfaces at the end of the metal material is pressed, and the other pair of surfaces are preformed by rolling from the end surface toward the center.

That is, one end of the metal material is roll pressed only once, and the remaining surfaces are preformed by rolling.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 6 of the accompanying drawings.

FIG. 2 shows a schematic diagram of a continuous rolling line 10 used in an embodiment of the present invention. This rolling line 10 is provided with a soaking furnace 12 that soaks the continuously cast bloom (U/4 piece) 14 to a predetermined temperature. A roller table 16 for conveying the bloom 14 extends from the soaking furnace 12 and conveys the bloom 14 to each rolling device. A blooming mill 18, a bloom mill 20, and a billet mill 22 are arranged in this order on the roller table 16.

Next, the operation of this embodiment will be explained.

A steel slab continuously cast by a continuous casting machine (not shown) is weighed into a bloom 14 of a predetermined size, and then heated to a predetermined concentration in a soaking furnace 12, as shown in FIG. The bloom 14 has a rectangular cross section, and its short side is placed on the conveyor 7-7/L/16. The bloom 14 heated in the soaking furnace is conveyed to a blooming mill 18 by table rollers 16.

In blooming rolling 8118, first preforming step 24 is performed. In this first preforming step 24, as shown in FIGS. 3 and 4, the leading and trailing ends of the bloom 14 are pressed by rolls of blooming 1118 to form thin sections.

In this case, the edges of the bloom are rolled by the blooming roll 24.26.
Then, as shown by arrow A in FIG. 3, the upper roll 32 is lowered toward the lower roll 34 for pressing. As shown in FIG. 4, the bloom 14 pressed in this manner has arc-shaped recesses 36.38 formed in a pair of opposing surfaces (short side surfaces) 28.30.

Next, the bloom 14 is laid down, that is, the pair of long sides 4
0.42 in the vertical direction, the indentation rolling step 44 is performed. In the push-rolling step 44, as shown in FIG. 5, the rolling rolls 32, 34 are rotated in the direction of arrow C from the front or rear end of the bloom 14 toward the center. Then, it is rolled approximately 100 times from the end face.

After the front end and rear #i1 portion 26 of the bloom 14 are preformed in this manner, the bloom 14 is conveyed to a rolling step 46 as shown in FIG. In the rolling step 46, as shown in FIG. 2, the material is rolled to a predetermined thickness using a bloom mill 20 or a billet mill 22.

The rolling results comparing this example and the conventional method are shown in FIG. 6 for the leading end (top) and trailing end (bottom) of the steel billet after rolling. The vertical axis indicates the distance from the end surface of a portion where an external surface defect or a mechanical vibrator defect occurs after rolling. Here, external defects include cracks, etc.
Mechanical defects are phenomena such as cavities. As is clear from the graph in Figure 6, it is approximately 150m from the conventional end face.
According to this invention, defects have occurred up to about 101 m.
It can be reduced to 00II1. That is, according to the present invention, the number of defective parts of a steel piece can be reduced to about 2773 compared to the conventional method.

Furthermore, according to this embodiment, preforming by roll press is performed only once, so compared to the conventional preforming by two presses, preforming takes less time and production efficiency can be improved. .

This invention is not limited to the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

For example, when preforming an end part, pressing and rolling are performed using a pair of blooming rolls, but the invention is not limited to this.
A similar effect can be obtained even if preforming is performed continuously by pressing and rolling. Furthermore, in this case, after pressing the end portion, the plume can be advanced without returning and preformed by rolling with vertical rolls, which saves time and can further improve production efficiency.

[Effect of the invention] According to this invention, when preforming the end of a metal material,
Since the roll press is performed only once, production efficiency can be improved, and since the entire circumferential surface of the edge is preformed, defects such as fishtails can be reduced, making it possible to improve the production efficiency of the steel billet. Yield can be improved.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing a method for rolling metal materials according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a rolling line according to an embodiment of the present invention, and FIG. 3 is a press at the end. Fig. 4 is a side view showing the condition, Fig. 4 is a perspective view showing the bloom after pressing, Fig. 5 is a side view showing the pressing process, and Fig. 6 is the length of the defective part of the steel billet after rolling. It is a graph diagram shown in comparison with. 14... Plue 7 (metal material), 24... Press preforming process, 44... Pressing process, 52 Rolling process. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure 114

Claims (1)

[Claims] One end of the metal material is pressed with a pair of rolling rolls to form a thin wall part on a pair of opposing surfaces of the metal material, and then the other pair of surfaces adjacent to the pair of surfaces are pressed from the end to the center. The edges are preformed by rolling towards
A method for rolling a metal material, which comprises rolling the metal material after the preforming.