JPH0335005B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The technical content described in this specification regarding the hot slab width rolling method and width rolling press apparatus is particularly applicable to long-term hot slab width rolling techniques. This paper proposes the development results of a hot slab width reduction method and press equipment that are advantageous for continuous operation.

Direct rolling (HDR) and hot charge rolling by synchronized operation of a continuous casting machine and a hot strip mill have great advantages such as energy saving, labor saving, and shortening of process time. It is possible to increase continuous casting capacity, reduce surplus slabs by integrating materials, and significantly improve operational efficiency by synchronizing continuous casting and hot rolling.
As a countermeasure, there is a trend to introduce large reduction technology that increases the amount of width change in hot slabs.

(Prior art) Conventionally, the width reduction of hot slabs has been carried out by the V-H rolling method, but there are many problems such as poor width reduction efficiency and increase in clotup loss. There were problems. Therefore, in recent years, a more effective width reduction method has been developed, which is a sizing technology that reduces the width direction over the entire length of the slab (Japanese Patent Laid-Open No. 59-101201, Japanese Patent Laid-Open No. 60
-Refer to Publication No. 203304) has been introduced.

(Problems to be Solved by the Invention) By the way, in width reduction using the above-mentioned sizing technique, the following problems occurred in the anvil due to particularly long press operations.

In other words, as the anvil becomes hot, deformation occurs due to the generation of a temperature gradient within the anvil.

(b) Wear is accelerated due to softening during tempering.

C. Heat cracks occur due to rapid cooling of the anvil surface.

D. Plastic flow occurs due to thermal stress on the surface.

For this reason, the life of the anvil is extremely short during width reduction of hot slabs, which is disadvantageous in that it leads to an increase in the cost of hot coils.

It is an object of the present invention to provide a width rolling method and a press apparatus that do not cause the above-mentioned inconveniences even if pressing work is performed for a long time when a hot slab is width rolled continuously over its entire length.

(Means for Solving the Problems) The present invention provides a means for reducing the width of the hot slab by forcing the width reduction anvils, which are paired with each other across the hot slab conveyance path line, to move toward and away from each other. A hot slab width reduction method (first invention) characterized in that, in carrying out the reduction, a plurality of pairs of individual width reduction anvils are prepared and used alternately by shifting them in a direction perpendicular to the above-mentioned mutual movement. In addition, the present invention includes a plurality of pairs of width reduction anvils facing each other across a hot slab conveyance path line;
An anvil holder for holding these width reduction anvils in a stacked manner, a slider block to which this anvil holder is attached so that it can be shifted up and down, and a thrust device connected to this slider block to force the width reduction anvils to move forward and backward relative to each other. This is a hot slab width reduction press device (second invention) comprising:

FIG. 1 shows one side of the main part of a hot slab width reduction press apparatus suitable for carrying out the present invention, and FIG. 2 schematically shows the entire apparatus.

In the figure, 1 is a plurality of pairs of width reduction anvils (1', 1'' in this example) facing each other across the hot slab conveyance path line, and 2 is an anvil holder that holds the width reduction anvils 1 in a stacked manner. , 3 is a slider block, 4 is a hydraulic cylinder that moves the anvil holder 2 up and down, 5 is the press main body, 6 is a connecting rod connected to the back of the slider block 3, 7 is a crankshaft, 8 is a speed reducer, and 9 is a drive device.

As shown in FIG. 1, this width reduction press device has an anvil holder 2 that holds a plurality of pairs of anvils 1 (1', 1'' in this example) in a stack, and a slider block via a hydraulic cylinder 4. 3, it is built in so that it can be shifted up and down.

Further, the slider block 3 with the anvil holder 2 attached has a connecting rod 6 on its back side,
It is connected to a drive device 9 via a crankshaft 7 and a speed reducer 8, and the anvil 1 is moved back and forth along a pair of grooves formed in the press body 5.
(1', 1'') is designed to force mutual forward and backward movement (see Figure 2).

(Function) In order to reduce the width of a hot slab using the above device, first, as shown in Fig. 3, the opening degree W of the anvil 2, the amplitude 2a, and the transport distance of the hot slab per unit time given below. Set L in advance.

L=(2a-α)/tanθ L: Conveyance distance (mm) θ: Entrance side inclination angle α: Allowance (mm) The slider block prevents the mutual advance and retreat of the anvil 1 placed opposite the hot slab conveyance path line. 3
One cycle consists of releasing the anvil 1 → conveying the hot slab → reducing the width while forcing the reciprocating motion of the hot slab, and by repeating this process, the hot slab that is being fed sequentially is continuously reduced in width to a predetermined width. It's something to push down.

In particular, in this invention, each time a predetermined width reduction step is completed, for example, each time the width reduction of one hot slab is completed, the hydraulic cylinder is controlled to shift the anvil 1' located on the pass line of the hot slab to another one. Position the anvil 1'' on the above pass line and continue to perform width reduction. After shifting the anvil 1'', the anvil 1', which is now in a standby state, is heated by a cooling device (not shown) during the width reduction by the anvil 1''. It is forced to cool down in preparation for the next width reduction (see Figure 1).

Figure 4 shows two pairs of anvils 1 and one hot slab.
This is an example showing an operation pattern when the anvils 1' and 1'' are alternately shifted each time the main width reduction is performed.The present invention is designed to shift the anvils 1' and 1'' alternately each time a predetermined width reduction process is completed. This makes it possible to advantageously prevent a significant temperature rise in the anvil that would otherwise occur during long width reduction operations.

Here, the anvil 1' is stacked on the anvil holder 2,
Although not shown, it is desirable to have a structure in which a gap (not shown) is provided between the 1'' laminations or a heat insulating and heat resistant resin is inserted to minimize heat transfer between the anvils.

(Example) Using the width reduction press shown in Fig. 2, the length was
10.5m, width 1500mm, thickness 220mm, initial temperature 1200℃
Width reduction of the hot slab was carried out with a reduction amount of 300 mm.

The working time for width reduction was 3 hours, and hot slab 1
Each time the width of the book was reduced, the anvils 1' and 1'' were shifted alternately. During the width reduction work, the anvils in the standby state were forcedly cooled by spraying a mist of cooling water onto them.

For comparison, a pair of anvils were used to reduce the width of the hot slab. After the width reduction work was completed, the surface temperature and Mises stress of the anvil were investigated.

When performing width reduction using a pair of anvils,
The surface temperature is 507℃, and the Mises stress is
On the ^other hand, when anvils 1' and 1'' were shifted up and down alternately to lower the width, the surface temperature was 421°C and the Mises stress was 65 kgf/mm2.
It was f/ ^mm2 .

(Effects of the invention) According to this invention, it is possible to prevent as much as possible the temperature rise of the anvil that conventionally occurs when width reduction of hot slabs is carried out, thereby extending the life of the anvil and increasing the efficiency of width reduction work. At the same time, it is possible to reduce the manufacturing cost of the hot coil.

[Brief explanation of the drawing]

1 is a hot slab width reduction press apparatus suitable for carrying out the present invention; FIG. 2 is a perspective view of essential parts of a combination structure of an anvil 1, an anvil holder 2, a slider block 3 and a hydraulic cylinder 4; The figure is an explanatory diagram showing the method of width reduction of a hot slab, and FIG. 4 is a graph showing the operation pattern of width reduction.

Claims (1)

[Scope of Claims] 1. In carrying out the width reduction of the hot slab by forcing the width reduction anvils, which are paired with each other across the hot slab conveyance path line, to approach and separate from each other, A method for width reduction of a hot slab, characterized in that a plurality of pairs of width reduction anvils are prepared and used alternately by shifting them in a direction orthogonal to the above-mentioned mutual movement. 2. A plurality of pairs of width reduction anvils facing each other across the hot slab conveyance path line, an anvil holder that holds these width reduction anvils in a stacked manner, a slider block to which the anvil holder is attached so that it can be moved up and down, and A hot slab width reduction press device comprising a thrust device connected to the slider block and forcing the width lower anvils to move forward and backward relative to each other.