JPH09277004A - Roll for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give the effect to the restraint of heat conduction at the edge parts of a cast slab by specifying a distance from the surface of a roll to a covered groove and the cross sectional area of the groove and arranging plural cooling water holes. SOLUTION: A through-hole 7 is arranged at the axial center of the roll body 1. The through-hole 7 is used to a water-passage hole for water cooling. On the outer peripheral part at the center of barrel longitudinal direction of the roll body 1, plural surface water-passage grooves 9 are arranged in the range of 1/3-4/5 length to the barrel length and both end parts thereof are communicated with the through-hole 7 for water cooling through branched water passage holes 8. The groove 9 is closed with a groove covering material 2, and fixed with welder parts 5. The groove covering material 2 is covered with a high strength alloy material builtup welding layer 3 and further, covered on this builtup welding layer with a builtup welding layer or a thermal-spaying coating layer 4 to form a roll surface layer. Then, the distance from the surface layer to the covered groove 9 is 20-70mm and the cross sectional area of one round groove or square groove 9 is 3-20% to the outer diameter area of the roll 1 and the number of the cooling water holes (grooves 9) is made to 4-64 pieces. By this structure, the high durable continuous casting roll having sufficient strength can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll for continuous casting of steel or the like, and more particularly to a water-cooled continuous casting roll which is excellent in oxidation resistance, wear resistance, heat resistance and thermal shock characteristics for high temperature cast pieces.

[0002]

2. Description of the Related Art In a continuous casting roll, a cast high-temperature cast piece comes into direct contact with the roll, so that the roll receives bending heat to cause bending deformation and runout. Therefore, the compressive force applied to the cast piece is not constant, and quality defects such as internal cracks and center segregation occur in the cast piece, which has become a problem. For this reason, revolver rolls, sleeve rolls, etc. have been used that allow cooling water to pass through from the roll center axis to cool the entire length of the surface layer.

However, in these rolls, since the entire length of the roll is cooled, the roll is deformed by uneven heat, which is still insufficient as a measure against local heating. For example, in JP-A No. 64-87045, a surface cooling roll is proposed, but there is no clear regulation on the cooling width,
It was still insufficient as a measure against uneven heat.

[0004]

The surface cooling roll has a certain effect to prevent overheating of the entire roll and to reduce deformation and runout of the entire roll length, but the surface temperature difference in the roll axial direction still exists. . Moreover, the temperature of the edge portion in the width direction of the cast piece was lowered by the full length cooling, and the quality defect of the cast piece was likely to occur. Further, in order to directly roll the cast piece, the slab edge has to be reheated, and a separate measure is required. The present invention solves the above-mentioned conventional problems, even if the cast piece comes into contact with the continuous casting roll, there is little heat removal of the cast piece slab edge, and the roll surface layer portion has oxidation resistance, wear resistance, corrosion resistance, and heat resistance. It is an object of the present invention to provide a water-cooled continuous casting roll having excellent properties and thermal shock characteristics.

[0005]

In order to achieve the above object, the inventors of the present invention have conducted extensive studies and found that it is effective to cool only the central outer peripheral portion of the roll in the axial direction. The invention was completed. The present invention made based on the above findings, in the outer peripheral portion of the roll in the cylinder length direction,
In the range of 1/3 to 4/5 of the body length, a plurality of roll cooling water passage capped grooves are provided, and both ends of the groove are communicated with the water passage holes of the roll shaft center by the water passage holes. The distance from the roll surface layer to the covered groove is 20 to 70 mm, the cross-sectional area of one circular groove or square groove is 3 to 20% of the roll outer diameter area, and 4 to 64 cooling water holes. The gist is a water-cooled continuous casting roll having the following features. The gist of the present invention is also a water-cooled continuous casting roll in which the roll cooling water passage cover groove is provided in parallel or spirally with respect to the axis.

Further, according to the present invention, a cooling water groove is formed on the outer periphery of the center of the roll in the cylinder length direction, and both ends of the groove are communicated with the water holes of the roll shaft center by the water holes. A strip material for groove lid, a multi-divided cylindrical material or a spiral strip-shaped lid material is welded and fixed, and a build-up welding layer of a material having durability equal to or higher than that of a roll material is provided on the lid material, A water-cooled continuous casting roll having a material coating layer having oxidation resistance, abrasion resistance, and heat resistance formed thereon, and stress-relieved as required, is the gist of the invention.

A cooling water groove is formed on the outer periphery of the center of the roll in the cylinder length direction, and both ends of the groove are communicated with the water holes of the roll shaft center by the water holes, and oxidation resistance is provided outside the cooling water groove. Sleeve having heat resistance, wear resistance, and heat resistance is shrink-fitted, and if necessary, a more durable material is coated, one end of the sleeve is welded and fixed to the roll body, and the other end is a free end. A water-cooled continuous casting roll having a sleeve slip-off preventing metal member fixed to the surface of the side axial roll is also the subject matter of the present invention. Furthermore, on the inner surface of the groove for passage of the roll cooling water, the overlay welding layer of the corrosion-resistant alloy, the water-cooled continuous casting roll formed with either the corrosion-resistant alloy sprayed layer or the corrosion-resistant alloy plating layer, or in the cooling water channel A water-cooled continuous casting roll provided with a non-uniform flow device that causes roll cooling water to flow to the casting piece side of the water channel is also the subject matter of the present invention.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional side view of a roll of the present invention. Reference numeral 1 denotes a roll main body, and usually the roll main body is supplied with a through hole 7 in the axial center, and the through hole 7 remains as it is. It serves as a water passage hole for water cooling.

As shown in the cross section of FIG. 2 or FIG.
In the roll of the present invention, a plurality of holes 8 communicating with the axial through hole 7 are formed on both sides of the roll at the same distance from the center cc 'line at equal intervals from the outer circumference of the roll so as to be symmetrical positions.
The holes 8 allow the cooling water passing through the axial center portion to be guided to the outer peripheral portion of the roll 1.

On the outer surface of the central portion of the roll, the holes 8 on both sides are provided.
After performing a groove engraving process to form a circular groove or a square groove 9 that connects the cooling water to the roll axis, it is closed with the lid member 2 so as to be flush with the roll surface, and the cooling water guided from the hole 8 to the outer peripheral portion is closed. Use as a passage. The size of the hole 8 is approximately the same as that of the groove 9. Further, the water passage holes 7 have a size capable of supplying the required cooling water to each hole 8. Specifically, the cross-sectional area of one hole 8 is 3 to 20% of the cross-sectional area of the water passage hole 7 and is determined by the casting conditions. In order for the roll to exert a cooling effect without surface temperature unevenness during the casting rotation, a minimum of four circular grooves or square grooves 9 are required. Further, a circular groove having a cross-sectional area of 3% of the water passage hole 7 has a hole diameter of 8 mm or less, and if the hole diameter is smaller than this, manufacturing processing is difficult, so that a maximum of 64 grooves are formed. The lid member 2 is liquid-tightly fixed to the roll surface by the welded portion 5. After that, a build-up welding layer 3 of a high-strength and high-alloy material is provided on the entire surface of the roll including the lid material surface, and if necessary, a build-up welding layer of oxidation resistance, wear resistance and heat resistance material as a finishing layer. Alternatively, the thermal spray coating layer 4 is formed, and the stress relief heat treatment is appropriately performed for finishing.

In order to flow the cooling water into the hole 8, the water passage hole 7 is sealed with the plug 6 at the branch portion. As a result, the cooling water is distributed to one end of the roll as shown by the arrow, and the drift device 1
Water is discharged from 0, passes through the holes 8, the grooves 9, the holes 8 and the water holes 7 and is discharged from the other end of the roll. The drift device 10
As shown in FIG. 4, the tip has a structure in which a forced jet flow can be made in the direction of the hole 8, and the cooling water is more concentrated on the roll surface portion with which the cast piece comes into contact.

FIG. 5 shows the case where the cooling water passage 9 formed on the outer surface of the central portion of the roll is formed in a spiral shape, and the water passage hole 8 connecting the through hole 7 and the groove 9 is formed. Need only be formed one at each end of the groove 9, and the number of processing steps is reduced. The water passage groove 9 is formed liquid-tight by welding the lid member 2 or the winding strip plate 2 obtained by dividing the cylinder in the longitudinal direction, as in FIG. 1. The lid member 2 may be applied only to the portion where the groove 9 is formed, or may be applied to the entire roll surface.

FIG. 6 shows a structure in which a high-strength high-alloy pipe material 11 covering the entire surface of the roll is shrink-fitted as a groove cover material for passing cooling water. A pipe-shaped high-strength roll material is shrink-fitted in place of the high-strength high-alloy pipe material, and the surface thereof is covered with a build-up welding layer of oxidation resistance, wear resistance and heat resistance material similar to that shown in FIG. A thermal spray coating layer may be formed and stress relief heat treatment may be appropriately performed. The lid member 11 is fixed to one end of the roll by welding 12, and a shift prevention stopper plate 14 is welded to the other end. In the shrink fitting method, one end of the surface layer pipe material is preferably a free end to allow expansion and contraction. In order to enhance the liquid tightness between the roll and the lid material, it is effective to provide the seal metal layer 13 having a high coefficient of thermal expansion on the roll surface or the inner surface of the lid material 11 before shrink fitting the lid material.

Occasionally, the cooling water passing through the covered groove may corrode the inner surface of the groove 9 or cause scale to be clogged. These can be prevented by appropriately selecting the cross-sectional area of the groove portion, but as shown in FIG. 10, on the inner surface of the groove, the buildup welding layer 19 of the corrosion resistant alloy, the corrosion resistant alloy sprayed layer 19 or the corrosion resistant alloy or the metal plating layer 19 is formed. The formation of either of these is effective in preventing corrosion and scale generation. In this case, it is preferable that the overlay has an overlay of 0.1 to 5 mm on the inner surface of the groove. SUS30 as a meat filling material
A quaternary material may be used, or a self-fluxing alloy may be used. Electroless N
You may perform i plating. This corrosion-resistant build-up construction can also be applied to branch water passage holes, if necessary.

[0015]

As described above, the present invention mainly has a structure for cooling the central outer peripheral portion of the continuous casting roll, and the contact portion with the cast piece is cooled, so that the temperature drop at the roll barrel end is reduced. . That is, the temperature of the barrel end is higher than that of the conventional revolver roll having a groove for cooling water passage over the entire length of the roll barrel, and it is effective in suppressing heat removal of the cast slab edge.

The required cooling width of the continuous casting roll varies depending on the size of the cast piece to be manufactured, the roll size, etc., but is preferably about 1/3 to 4/5 of the body length, and the depth / position of the cooling water groove is
It is preferable to set the distance from the roll surface to the edge of the cooling water groove to 20 to 70 mm. The depth and position of the cooling water groove should be selected in consideration of uneven cooling, roll strength and cooling effect. One of the points for securing the strength of the buildup welded structure roll is to shift the position of the welded portion 5 of the lid member 2 in FIG. 1 to the outside of the cooling water passage hole 8.

Since the continuous casting roll of the present invention is water-cooled at the portion in contact with the cast piece, the surface temperature of the roll does not rise so much and it is resistant to thermal shock. Therefore, by selecting an oxidation resistant, abrasion resistant and heat resistant material for the surface layer material, a highly durable continuous casting roll having sufficient strength can be obtained. Of course, the same applies to build-up welding, and by selecting the chemical composition of the high alloy material, the durability at high temperatures can be further improved. Further, it is possible to provide a continuous casting roll having the same performance at a lower cost than the continuous casting roll made of a high alloy material as a whole, which is extremely useful industrially.

[0018]

EXAMPLES The present invention will be described specifically with reference to Examples.
This does not limit the invention. Example 1 In order to investigate the amount of deflection of the continuous casting roll, the material J
With IS SNCM220, roll bearing is φ100m
m × 311mmL, body size is φ120mm × 7
00mmL, 1/4 of the body length, 1 / of the body length on the outer periphery of the roll center with a 30mm diameter hole for cooling water passing through the roll center axis
3, 1/2 and 3/4 length, width 15mm depth 5mm
8 parallel grooves for passage of cooling water were provided at positions at a depth of 20 mm from the roll surface at equal intervals, and both ends of the grooves were communicated with the water holes 7 of the central axis by the water holes 8 having the same cross-sectional area. A SUS304 material having a thickness of 20 mm is attached as a lid material on the groove,
A test roll was made. In addition, a comparative test roll having the same dimension as the parallel groove for passage of cooling water in the entire body length and a cooling water passage hole having a diameter of 30 mm only in the central portion of the roll and having the same dimensions and the same main body material were prepared. .

The amount of deflection is measured as shown in FIG.
One side of the roll body rotating at 2 rpm
5. Heat with a burner 15 having a crater width of 600 mm so that the temperature near the roll surface becomes 350 ° C., and a cooling water nozzle 16 having a nozzle width of 600 mm is provided on the opposite side, and 6 liters /
A minute of cooling water (15 ° C) was sprayed. After heating and cooling were repeated 0.8 times while rotating the roll for 100 hours, the rotation of the roll was stopped and the bending of the roll due to thermal stress was measured with a gauge 17. The test results are shown in FIG. It was confirmed that when the cooling water passage groove length was longer than 1/3 of the body length, the amount of bending was small, and the quality and shape of the slab was improved.

Example 2 In order to investigate the effect of suppressing heat removal from the edge of the cast slab, a parallel groove for cooling water passage having a length of 1/2 of the body length was formed in the center under the same conditions as in Example 1. Using the above-described test roll and a comparative roll having parallel grooves for passage of cooling water in the entire length of the cylinder, the roll surface temperature was measured while rotating the roll under the conditions of Example 1 as shown in FIG. Figure 9 shows the test results
Shown in It can be seen that by cooling only the center of the roll, the surface temperature at the end of the roll increases. That is, since it is effective in suppressing heat removal from the edge of the cast slab, it is not necessary to heat the edge of the cast slab in the case of direct feed rolling, which is a great industrial effect.

[Brief description of drawings]

FIG. 1 is a sectional side view of a continuous casting roll of the present invention.

FIG. 2 is a partial cross-sectional perspective view showing an arrangement of roll cooling water through holes of a circular groove.

FIG. 3 is a partial cross-sectional perspective view showing an arrangement of roll cooling water through holes of a square groove.

FIG. 4 is an explanatory perspective view showing a range of action of the deflector.

FIG. 5 is a partial cross-sectional perspective view showing an arrangement of spiral-direction roll cooling water passage holes.

FIG. 6 is a sectional side view of the continuous casting roll of the present invention in which a roll surface layer material is shrink-fitted.

FIG. 7 is an explanatory diagram for testing the continuous casting roll of the present invention.

FIG. 8 is a graph showing the results of a bending test of a continuous casting roll.

FIG. 9 is a graph showing an end heat removal state of a continuous casting roll.

FIG. 10 is a cross-sectional view of a portion in which a build-up welding layer of a corrosion-resistant alloy is formed on the inner surface of a groove with a lid.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Roll main body 10 Drift device 2 Groove cover material 11 Shrink fitting pipe material 3 High-strength and high-alloy material build-up welding layer 12 Attachment welding part 4 Build-up or thermal spray coating layer 13 Seal material build-up part 5 Groove cover welding part 14 Fallout prevention Stopper 6 Water flow prevention plug 15 Heating burner 7 Shaft center water flow hole 16 Cooling water nozzle 8 Branch water flow hole 17 Bending measurement dial gauge 9 Surface water flow groove 19 Groove on the inner surface of groove

Claims (6)

[Claims] 1. A plurality of lid cooling grooves for passing roll cooling water are provided on the outer periphery of the center of the roll in the cylinder length direction in the range of 1/3 to 4/5 of the cylinder length, and water is passed through both ends of the groove. It is connected to the water hole of the roll axis by a hole, the distance from the roll surface layer to reach the covered groove is 20 to 70 mm, and the cross-sectional area of one circular groove or square groove is relative to the roll outer diameter area. 3 to 2
A water-cooled continuous casting roll having 0% and 4 to 64 cooling water holes. 2. The water-cooled continuous casting roll according to claim 1, wherein the lid cooling groove for passing the roll cooling water is provided in parallel or spirally with respect to the axis. 3. A cooling water groove is formed on the outer periphery of the center of the roll in the longitudinal direction of the roll, and both ends of the groove are communicated with water holes of the roll shaft center by water holes, and a groove lid is provided on the cooling water groove. A strip material, a multi-divided cylindrical material or a spiral strip-shaped lid material is welded and fixed, and a buildup welding layer of a material having durability equal to or higher than that of a roll material is provided on the lid material, and the lid material is provided thereon. The water-cooled continuous casting roll according to claim 1 or 2, wherein a material coating layer having both oxidation resistance, abrasion resistance, and heat resistance is formed and stress-relieved if necessary. 4. A cooling water groove is formed on the outer periphery of the center of the roll in the longitudinal direction of the roll, and both ends of the groove are communicated with water holes of the roll shaft center by water holes, and oxidation resistance is provided outside the cooling water groove. Sleeve having heat resistance, wear resistance, and heat resistance is shrink-fitted, and if necessary, a more durable material is coated, one end of the sleeve is welded and fixed to the roll body, and the other end is a free end. The water-cooled continuous casting roll according to claim 1 or 2, wherein a sleeve slip-off preventing metal fitting is fixed to the surface of the side axial roll. 5. On the inner surface of the groove with a lid for passing roll cooling water,
The water-cooled continuous casting roll according to any one of claims 1 to 4, wherein a build-up welded layer of a corrosion-resistant alloy, a corrosion-resistant alloy sprayed layer, or a corrosion-resistant alloy plated layer is formed. 6. The water-cooled continuous casting roll according to claim 1, further comprising a drift device in the cooling water passage for flowing the roll cooling water to the casting piece side of the water passage.