JPS59199152A - Continuous casting method of thin plate - Google Patents

Abstract

PURPOSE:To prevent surface oxidation and to eliminate the need for a descaling stage by casting a thin billet with two casting rolls in an inert gaseous atmosphere and drawing the billet along plural cooling rolls thereby cooling the billet to a specific temp. or below. CONSTITUTION:Casting rolls 1, 1' are formed of copper or a copper alloy or a steel material and contain internally water cooling mechanisms. These rolls are made into a large diameter to increase the contact area with a molten metal 4. Stationary gates 7 of a refractory material are provided to both ends of the rolls 1, 1' so as to inscribe the same. The molten metal 4 is charged into the space formed of the two rolls 1, 1' and the two gates 7. Then the solidified shell formed when the metal 4 is cooled by contacting with the surfaces of the rolls 1, 1' is united to one body to form a billet 3. The billet 3 is cooled by moving along cooling rolls 2, 2', 2'' contg. internally water cooling mechanisms. The casting rolls and cooling rolls are in the system substd. with inert gas and the temp. of the billet emerging to the outside of the system is maintained at <=150 deg.C and the surface oxidation of the billet is obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin plate continuous casting method that omits the descaling step and prevents a decrease in yield due to scale loss pressure.

Conventionally, the method of manufacturing cold rolled steel sheets that omitted the hot rolling process was as follows:
Thin plate slab (2 to 5 pieces thick) → Descaling (e.g. pickling)
Cold rolled steel sheets are manufactured through the process of → cold rolling → annealing. In this process, the surface of the slab is oxidized and undergoes a descaling process.

Therefore, the yield is reduced due to oxidation of the slab (school loss), and the process becomes complicated because it includes descaling, which causes an increase in costs.

The present invention provides a method for manufacturing cold-rolled steel sheets that eliminates the conventional hot rolling process described above. This was done with the aim of preventing oxidation of the surface of the slab during production of thin plates and omitting the descaling process.

That is, the present invention uses a continuous casting apparatus having two casting rolls to continuously cast a strip-shaped thin plate of iron, non-ferrous metal or alloy, in an inert gas atmosphere, and immediately casts the obtained slab into a cast iron. The present invention relates to a continuous thin plate casting method characterized in that the slab is cooled along a plurality of cooling rolls in an active gas atmosphere until the slab temperature becomes 150'OC or less.

To the method of the present invention? In this case, the slab obtained by the twin-drum continuous thin plate casting apparatus is immediately cooled by passing it along internal water-cooled rolls. In this case, casting equipment?
The cooling hole for the slab is located in a system purged with an inert gas such as Ar, and the slab comes out of the system when the temperature reaches about 150° C. or less and is wound up. S, slab temperature is 150
When it exits the system at a temperature higher than 'O' (when it comes into contact with the atmosphere), the surface is oxidized and school is generated.

In this way, in the method of the present invention, since the surface of the slab is not completely oxidized, the subsequent descaling step (pickling step) can be omitted and cold rolling can be performed immediately.

FIG. 1 is a diagram showing an example of an embodiment of the method of the present invention.

In Fig. 1, 3 is a thin plate slab, and 5'1' is a thin plate slab 6.
Water-cooled casting rolls 2.2', 2' are the slab 3
4 is a molten metal; 5 is a molten metal 4 such as molten steel;
6 is a ladle for pouring the molten metal 4.

The water-cooled casting rolls 1, 1' are installed horizontally and are driven to rotate (in the direction of the arrow) by a drive device (not shown).The water-cooled casting rolls 1, 1' are made of copper, copper alloy, or steel, for example. , has a built-in water cooling mechanism (see Fig. 2), and has a considerably large diameter roll to obtain a large contact area with the molten metal 4.
A fixed weir 7 made of refractory material is inscribed in both ends of the a-built o-/I/1.1' to seal the sides. vinegar,
Molten metal 4 is poured into a space formed by two water-cooled casting rolls 1, 1' and two fixed weirs 7. The molten metal 4 comes into contact with the surfaces of the water-cooled casting rolls 1 and 1' and is cooled, resulting in a solidified shell that is integrated into a slab 3. The solid slab 3 is cooled by passing along copper cooling rolls 2.2' and 2', which have a built-in water cooling mechanism similar to the water cooling rolls 1 and 1'.

Furthermore, the above twin drum casting machine 2 and the roll cooling zone are in a system purged with an inert gas such as Ar, and the temperature of the slab exiting the system is about 150'0 or less. X, as mentioned above, when the slab temperature exceeds 150°O, it comes out of the system (
When exposed to the atmosphere, the surface is oxidized and school is formed.

In the second round, water-cooled casting roll 1. 1/, cooling roll 2.
2', f shows a cross-sectional view of an example, and FIG.
It is an enlarged view of the alpha part of pronation.

8 in FIG. 2, 11 indicates the roll surface, and 12 indicates the cooling water inlet.

According to the method of the present invention detailed above, the following effects can be achieved.

(1) Thin plate casting machine and slab cooling roll cooling zone C2
. The school process (pickling process) can be omitted.

(2) Yield is improved because there is no scale loss due to oxidation.

(3) The cooling rate of the slab is high due to roll cooling.
The device can also be made more compact.

Next, the dimensions and performance of the structural members when steel is cast by the method of the present invention are shown.

(1) Water-cooled casting rolls 1, 1' Made of copper alloy and internally water-cooled, the roll diameter is 1800 mm.
A roll having a width of 1500 square meters was used. The slab size is 4
++o+”X 1200 gmW, and the roll rotation speed was about 15 m/sin.

(2) Slab cooling rolls 2, 2', ! Made of steel and internally water-cooled, the roll diameter is 1000mmφ and the roll width is 1.
500. , , were arranged in three side rows, and the roll spacing was approximately 200 tones. The slab plate thickness is 41Elt, and the slab temperature just before contacting the slab cooling roll is 1300~13
50'C! The temperature of the slab after contacting the three cooling rolls was approximately 150'0.

(4) Molten metal 4 temperature The molten metal 4 temperature in tundish 5 is the same as normal steel material.
00-1560'O.

The surface of the slab produced under the above conditions was not oxidized at all, the descaling process could be omitted, and there was no scale loss due to oxidation (yield was improved).

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an embodiment of the method of the present invention. Figure 2 tAJ, (BJ is roll 1°1', 2 in Figure 1
, 2', 2 is a cross-sectional view of an embodiment of the internal water cooling system in 2. Figure 2 tBJ is an enlarged view of the α section of Figure 2 (AJ). −

Claims (1)

[Claims] When continuously casting thin strips of iron, non-ferrous metals, or alloys, a continuous casting machine with two casting rolls is used to cast in an inert gas atmosphere, and the obtained slab is immediately cast in an inert gas atmosphere. A thin plate continuous casting method characterized by cooling the slab along a plurality of cooling rolls until the slab temperature becomes 150"C or less.