KR810000591B1 - Continuous casting mould for metals difference to melting and solidification temperature - Google Patents

Abstract

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Description

Continuous casting mold of metal with large difference in melting temperature and solidification temperature

1 is a cross-sectional view of a continuous casting mold according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to molds for continuous casting of metals having a large difference in melting temperature and solidification temperature, such as white cast iron, high alloy special cast iron, high-speed coating steel, and high alloy copper alloy.

Conventionally, a vertical continuous casting method which is applied to a metal which is hard to cause defects due to quenching such as ordinary steel or stainless steel, and which is suitable for mass production, is directly adopted into a water-cooled metal mold. Moreover, the horizontal continuous casting method which set the graphite die in the water cooling machine is employ | adopted for casting of gray cast iron and the copper alloy copper melting temperature comparatively low, and graphite and a metal which do not react in a molten state.

In the case of continuous casting of a metal that reacts with graphite using a graphite die, the portion where the molten metal is in contact with the graphite is eroded, so the life is remarkably shortened, and when solidified, a sticking phenomenon occurs and breaks for a short time. (Iii) or it becomes impossible to draw out and becomes unusable, and continuous casting becomes difficult. Metals with a large difference in melting temperature and solidification temperature, for example, white cast iron, high alloy special cast iron, high-speed coated steel, high Cu, Cr, Sn-containing copper alloy copper have a large difference between the melting temperature and the solidification temperature. Compared with a small metal, a solidified angle cannot be obtained, and continuous casting is difficult due to inferior fluidity of molten metal.

The present invention uses a refractory material that lubricates by slight abrasion other than graphite in the die in contact with the molten metal, thereby avoiding sticking at the contact portion with the applied metal, thereby reducing the By using a refractory material, continuous casting of the said metal that continuous casting is difficult is made possible easily.

In order to prevent the breakage of the protrusion on the side of the water tank of the die in contact with the applied metal, the present invention is to fix the protrusion as an inner compound and a metal protector, and to fix the protector to a water cooling jacket. This improves the durability of the continuous casting of the metal, which is difficult to continuous casting, and succeeds in the continuous casting for a long time.

Since the die of the first stage of the continuous casting mold according to the present invention comes into contact with the molten metal, it is possible to use a lubricant having a lubricity other than graphite that does not react with the applied metal, for example, metal nitride. Great effect. Since metal nitrides generally do not get wet with molten metal and have excellent lubricity with slight wear, the force to pull out the solidification ingot may be a little, or the breakage of the solidification angle of the metal may occur. none.

Therefore, even when the molten metal reacts with graphite, it is possible to continuously cast the second stage die having the same inner diameter as the die of the first stage by using graphite having a hardness equal to or less than that of the first stage die. .

In the horizontal continuous casting method in which a continuous casting agent of excellent quality can be obtained in continuous casting of metal, meandering phenomenon of the continuous casting material due to partial non-uniform cooling of the continuous casting material occurs, which is then bent in the casting mold. It is known that the power is crazy to destroy the die of the mold.

In order to prevent breakage of the die due to meandering, the first end refractory die protrudes toward the water tank side rather than the end of the water cooling jacket, and the fixing ring of the refractory is fixed with a metal protective device. In other words, the protective device and the water cooling jacket are combined mechanically and strongly. The first stage refractory, the second stage refractory made of graphite, the water cooling jacket, the fixing refractory, and the metal protective device joined in this manner are integrated to prevent the die from being destroyed by meandering.

Metals with a large difference in melting temperature and solidification temperature that are difficult to continuous casting, for example, white cast iron Fe-C-Cr alloy, Fe-CW alloy, Fe-C-Mo alloy, Fe-C-Ti alloy, Cu-Cr alloy Alloys, such as Cu-Co alloys and Cu-Sn alloys, in which the difference between the melting temperature and the solidification temperature in the chemical composition in which the process reactions occur is not more than 100 °, a firm solidification angle cannot be obtained. Since the solidification angle cannot resist the force generated by the pulling force and the frictional force and is destroyed, there is a difficulty in that stable continuous casting is not realized. Also in terms of quality, the fluidity of the applied metal is poor in the temperature range until it solidifies, and thus there is a defect that the surface state and internal properties are remarkably degraded.

On the other hand, in this invention, in order to eliminate the said fault, the 1st stage refractory body which lubricates by the slight abrasion other than the graphite of the length more than once drawn out to the injection end side is inserted, and this refractory on the injection end side is The length of the refractory material of the second stage is more than 1 times or more than 4 times the length of the refractory material of the 1st stage, and it protrudes 1 times or more of the thickness of this refractory to the water tank side rather than the cross section of a water-cooled mold. Since it is formed as a mold inserted into the mold, it is effective for continuous casting of a metal having a large difference in melting temperature and solidification temperature, and excellent quality makes it possible to draw the continuous casting material for a long time.

This invention is demonstrated in detail again by FIG. 1 which shows one form of this invention.

The lubricious first stage refractory die 1 and the graphite refractory die 2 are inserted into the water cooling jacket 3, and the injection end side of the die 1 protrudes from the water cooling jacket 3 to fix the refractory for fixing. It is inserted in (4). The fixing brick 4 is fixed by the metallic protective tool 6 and fixed to the water cooling jacket 3 by the fastening bolt 7. The metal ring protector 6 at the tip of (1), (2), (3), (4) and (6), which is fixed mechanically integrally, is attached to the mounting brick (5) of the molten metal holding passage (8). It is inserted and watertight is maintained.

Solidification of the ingot begins near the inner surface of the die 1 at the position where the fixing refractory 4 and the water cooling jacket 3 are connected. In the intermittent drawing, the cross section S of the solidification angle grown while pulling is stopped is moved to the position of (S ') by drawing, and the tip of (S') is always melted since it is in the die 1 The metal and the die 2 do not come into contact with each other. The solidification front end surface moved to the position of S 'grows to the position of S while drawing is stopped. Since the length of the die 1 needs to protrude to the molten metal side rather than the front end S of the solidification angle cross section immediately before being pulled out, the length a of the protruding portion to the length L of the contact portion with the water cooling jacket 3. Needs to be added. The length (L) needs to be longer than the length of one draw, and the value is appropriately in the range of 1 to 5 times the length of the draw, and does not need to be lengthlessly used. The protrusion a needs a length equal to or greater than the thickness b. When the projection a is shorter than the thickness b, solidification extends to the tip of the die 1, leading to an increase in the resistance to be pulled out, causing wear or destruction of the tip of the die 1, or This may cause cracking, sticking, or sticking, and may also cause breakouts or pulling out.

The projection a does not have to be unnecessarily lengthened. The thickness (b) is 5 ~ 20mm is suitable, if thicker than this, the cooling rate is small, the productivity is lowered. If it is thinner than this, it will not endure long time use by abrasion. The length m of the graphite die 2 needs to be 1 to 4 times the length l of the die 1, and if it is shorter than this, sufficient cooling capacity cannot be obtained. On the contrary, the service life is shortened. In addition, the thickness b 'does not necessarily need to be the same as (b). However, if the thickness b' is smaller than (b), the wear will shorten the life of the die 1, and if too large, the cooling rate will be unnecessarily delayed.

In continuous casting, the entire surface of the continuous casting material is not uniformly cooled, and localized cooling unevenness is likely to occur, and such cooling unevenness inevitably causes meandering phenomenon of the continuous casting material. The meandering phenomenon causes the casting material to exert bending force on the mold, and in the case of the mold which does not protect the base of the protrusion (a) of the die 1, it often causes the destruction of this part, making continuous casting impossible. It was. This problem can be completely avoided by using the fixing refractory material 4 fixed by the fastener protection device 6 fastened as the bolt 7.

Hereinafter, the effects of the present invention will be described according to the examples.

Example 1

Type of molten metal: alloy white cast iron

Main Chemical Composition, 2.5% C, 0.5Si, 0.5% Mn, 2.5% Cr

Difference between Melting Temperature and Solidification Temperature: 178 ℃ (1,301 ℃ -1,123 ℃)

Part size of metal nitride die: a = 15mm, b = 10mm, ℓ = 100mm, D60mm

Part size of graphite die: b '= 8mm, m = 200mm, D = 60mm

Under the above conditions, continuous casting was carried out using the mold indicated in the present invention at a length of 50 mm for one draw. As a result, drawing of continuous cast iron with a weight of 35,0 50 kg was carried out during drawing for 123 hours and 30 minutes. Could achieve. The mature biller averaged 60.5 mm pills.

Example 2

Type of molten metal: 13% Cr steel

Main Chemical Composition: 1.2% C, 0.5% Si, 0.6% Mn, 13% Cr.

Difference between Melting Temperature and Solidification Temperature: 230 ℃ (1430 ℃ -1200 ℃)

Part size of metal nitride die: a = 30mm, b = 15mm, ℓ = 150mm, A = 40mm × 350mm

=15mm, m=300mm, A=40mm×350mmPart size of graphite die:

= 15mm, m = 300mm, A = 40mm × 350mm

(A denotes the cross-sectional shape and dimensions inside the first and second stage refractory)

Under these conditions, continuous casting was carried out using the mold indicated in the present invention at a length of 70 mm, and continuous drawing was carried out with a weight of 32,800 kg while drawing for 97 hours and 50 minutes. there was. The feature shape had a thickness average of 42 mm and a width average of 352 mm.

Example 3

Type of molten metal: 24Cr cast iron

Main Chemical Composition: 2.3% C, 0.5% Si, 0.6% Mn, 24% Cr.

Difference between Melting Temperature and Solidification Temperature: 120 ℃ (1330 ℃ -1210 ℃)

Part size of metal nitride die: a = 25mm, b = 15mm, ℓ = 160mm, D = 8 0mm

=15mm, m=250mm, D=80mm

Part size of graphite die:

= 15mm, m = 250mm, D = 80mm

According to such conditions, continuous casting was carried out using the mold shown in the present invention at a draw length of 60 mm. As a result, the continuous casting material having a weight of 28,200 kg was drawn during the extraction for 75 hours and 30 minutes. Could. The characteristic shape became the square material of 80 mm in thickness average.

Example 4

Type of molten metal: high Cr copper alloy

Main Chemical Composition: 25% Cr, 75% Cu,

Difference in Freezing Temperature of Melting Temperature: 324 ℃ (1400 ℃ -1076 ℃)

Part size of metal nitride die: a = 35mm, b = 18mm, ℓ = 18mm, D = 90mmø

Part size of graphite die b '= 18mm, m = 250mm, D = 90mmø

According to these conditions, continuous casting was carried out using the mold indicated in the present invention by setting the length of one pulling to 80 mm. As a result, drawing of a continuous casting material of 52, 800 kg weight was carried out while pulling out for 148 hours and 35 minutes. Could be achieved. Characteristic type | mold acid became the square material of an average of 92 mm.

Example 5

Type of molten metal: recovered iron

Main Chemical Composition: 3.2% C, 1.8% Si, 0.5% Mn

Difference between Melting Temperature and Solidification Temperature: 137 ℃ (1260 ℃ -1123 ℃)

Part size of metal nitride die: a = 25mm, b = 15mm, ℓ = 160mm, D = 80mmø

Part size of graphite die: b '= 15mm, m = 250mm, D = 80mm

According to the conditions described above, continuous casting was carried out using the mold shown in the present invention at one drawing length of 75 mm, and it was possible to achieve drawing of a continuous cast material having a weight of 95,190 kg during drawing for 167 hours and 20 minutes.

The characteristic shape is an average of 82.5 mm square material, and according to the conventionally used graphite mold, only a continuous casting material of 7,500 kg weight is obtained in 12 hours and 50 minutes, and the remarkable effect of the present invention can be recognized by comparing the two.

Although the features and effects of the present invention have been described above with respect to horizontal continuous casting, the present invention can be applied to other types of continuous casting, for example, vertical or inclined continuous casting molds, and the like.

Claims (1)

An open mold having an injection end and an injection end, wherein in a continuous casting mold in which the injection end is directly connected to a water bath, the first stage refractory having lubricity other than graphite of one or more drawing lengths on the injection end side. The refractory on the injection end side protrudes at least one times the thickness of the refractory from the end face of the water-cooled mold to the water bath side, and the graphite refractory at the second end is 1 times the refractory at the first end on the injection end side. A continuous casting mold for metal having a large difference in melting temperature and solidification temperature, characterized by being formed into a mold inserted in a length of four times or more.

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