JP2012000658A - Mold for continuous casting and working method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold structure and a working method for the mold, which improve the fitting property of a sleeve and a water-cooling protector while making the simple structure of a bisected sleeve mold applicable, for a copper-alloy mold for continuous casting, in particular a carbon mold.SOLUTION: There is disclosed a mold for continuous casting, in which a U-shaped sleeve 13 bisected at its short-side is arranged on the inner wall of a water-cooling protector 11. In the mold for continuous casting, there are provided: a heat conductive sheet 14, which has compression restorability and is arranged on the long-side inner wall of the water-cooling protector; and an expanding means 18, which is arranged between the short-side bisected sleeves and pushes both sleeves against the long-side inner wall of the water-cooling protector via the heat conductive sheet.

Description

  The present invention relates to a continuous casting mold of a copper alloy, and more particularly to a continuous casting mold using a two-part sleeve and a method of construction thereof.

  Generally, continuous casting of a copper alloy is performed using a mold having a casting space with both ends open. The molten metal poured from one end of the mold is extracted from the inner wall of the mold and gradually solidifies from the contact surface with the inner wall of the mold while passing through the mold. By continuously pulling out the solidified ingot from the other end, a long ingot is continuously manufactured.

  Depending on the type and characteristics of the copper alloy to be cast, the material of the mold inner wall is copper, copper alloy or copper alloy plated, carbon sleeve inserted, or hollow carbon material. There is.

  In particular, a mold in which a carbon sleeve is inserted into the inner wall of a copper mold is superior to cooling in which the mold is directly brought into contact with a copper alloy or a plated surface in order to achieve uniform cooling of the ingot.

  There are two types of mold structures for inserting a carbon sleeve, one using a monolithic sleeve and the other using a split sleeve.

  In continuous casting of copper alloys, the cross-sectional shape can be broadly divided into round and rectangular depending on the application. Inserting a carbon sleeve in a round cross-section casting mold that produces materials such as cables, pipes, or round bars is relatively small and symmetrical with the cast ingot. It is common to insert (for example, patent document 1).

  However, rectangular cross-section casting molds for producing materials such as plates, strips, strips, etc. cannot insert carbon sleeves by shrinking due to the large ingot size and the large number of rectangular cross-sectional shapes.

  Therefore, a method of inserting a two-divided carbon sleeve by sliding and combining a four-divided carbon plate with a well and fixing it with an iron back plate is generally used.

  FIG. 6 shows a cross-sectional view of a prior art two-part carbon mold. In FIG. 6, the inner wall of the copper protector 21 provided with the cooling water channel 12 is combined with the carbon sleeve 22 divided into two U-shapes on the short side, and the outer surface dimension of the carbon sleeve 22 is the inner wall dimension of the copper protector 21. Insert smaller.

  FIG. 7 shows a cross-sectional view of a prior art quadrant carbon plate mold. In FIG. 7, an iron back plate 24 having a cooling water channel 12 provided therein is arranged in a well shape, and a carbon plate 26 is fixed to a long side side back plate 24 via a copper plate 25 by a fixing bolt 27. A structure in which the carbon plate 26 is directly fixed to the side-side back plate 24 by fixing bolts 27 is formed.

  In the case of continuous casting of copper alloy, the cooling conditions from the molten metal to complete solidification are severe, and if it is not cooled uniformly, the concentration of solute elements occurs at the inflection point of the temperature gradient, and the solvent Due to the eutectoid reaction with the elements, segregation occurs in the crystal grains and in the grain boundaries. This becomes a defect such as fogging or peeling in the processing process, and becomes a serious cause of lowering the ingot quality particularly on the longer side than the shorter side of the mold.

  In addition to appearance quality, the quality of the ingot by structure control is an important factor in the subsequent product processing steps. In continuous casting of a copper alloy, the uniformity of cooling is directly linked to the quality of the ingot, and therefore, adhesion between the sleeve and the water-cooled protector is required on the long side of the mold cross section.

  Further, since the sleeve on the inner wall of the mold is in direct contact with the solid metal ingot in addition to the high-temperature molten metal, frequent replacement work is required due to wear due to high temperature and friction.

JP-A-63-220948

  In the four-part carbon plate mold, the carbon plate 26 is pulled to the back plate 24 side by the fixing bolts 27. Therefore, the adhesion between the carbon plate 26 and the back plate 24 is excellent, and uneven cooling of the mold does not easily occur. However, the number of parts constituting the mold is large, and further, it is necessary to provide a female screw hole corresponding to the fixing bolt 27 in the carbon plate 26, which is inferior in maintainability and work efficiency.

  Although the two-part carbon mold has few parts and is easy to maintain, the carbon sleeve 22 divided into U-shapes is combined, so it is necessary to insert the copper protector 21 in a combined state at the same time. There is. In this case, unlike shrink shrinkage, strictly speaking, the outer diameter of the carbon sleeve 22 must be modified to be smaller than the inner diameter of the copper protector 21, and a minute gap is formed at this point. Further, in the copper protector 21 that has been used, the inner wall is corroded due to thermal deformation or oxidation, and if these are corrected, the planar accuracy is impaired. For these maintenance reasons, an air gap 23 is easily generated between the carbon sleeve 22 and the copper protector 21, and the cooling capacity is reduced due to the heat insulation effect of air during casting.

  The present invention has been made in view of such problems, and provides a mold structure for improving the adhesion between a sleeve and a water-cooled protector while utilizing the simple structure of a two-part sleeve mold, and a method for constructing the mold structure. Objective.

  The invention of claim 1 is a continuous casting mold in which a U-shaped sleeve divided into two on the short side is arranged on the inner wall of a water-cooled protector having a rectangular cross section. A continuous casting mold provided with a widening means for pressing the two sleeves against the inner wall of the long side of the water-cooled protector through the heat transfer sheet between the two divided sleeves on the short side. is there.

  The invention according to claim 2 is the continuous casting mold according to claim 1, wherein the heat transfer sheet is made of a graphite sheet.

  According to a third aspect of the present invention, the widening means comprises a key groove provided on the short side of the two-divided sleeve and a wedge that is inserted into the key groove to widen the two-divided sleeve. This is a continuous casting mold.

  A fourth aspect of the present invention is the continuous casting mold according to the third aspect, wherein the keyway has a depth of 50% to 70% of the thickness of the two-piece sleeve.

  In the invention of claim 5, when the two-divided sleeve is assembled and assembled, the dimensional difference between the outer surface of the two-divided sleeve and the inner wall of the water-cooled protector is 1.0 mm or more and 3.0 mm or less on the long side, and the short side Then, the continuous casting mold according to any one of claims 1 to 4, wherein the length is 0.5% or more and 1.0% or less of the long side length of the two-divided sleeve.

  According to a sixth aspect of the present invention, the water-cooled protector having a rectangular cross section, the two pairs of heat transfer sheets provided on the inner surface of the wide surface of the water-cooled protector, and the protector are provided so as to contact the inner side of the heat transfer sheet. Two pairs of U-shaped sleeves having an open end on the narrow surface side thereof, and a key groove formed at the end of the U-shaped sleeve on the water cooling protector side, the length of the short side when engaged Is a mold for a continuous casting machine, characterized in that it comprises two wedges having a width wider than the keyway width.

  The invention according to claim 7 is a method for constructing a continuous casting mold in which a U-shaped sleeve divided into two on the short side is arranged on the inner wall of a water-cooled protector having a rectangular cross section, and compressed on the inner wall of the long-side of the water-cooled protector. A heat transfer sheet having resilience is provided, and a widening means is provided between the two divided sleeves on the short side to press both sleeves against the long side inner wall of the water-cooled protector via the heat transfer sheet, and the widening means The continuous casting mold is pressed by pressing the two-divided sleeve against the inner wall of the water-cooled protector via the heat transfer sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of a sleeve and a water-cooled protector can be improved utilizing the simple structure of a 2 split sleeve mold.

It is sectional drawing which shows one embodiment of this invention. It is a partially broken perspective view of FIG. It is the AA line side view of FIG. FIG. 2 is a partial cutaway perspective view taken along line AA in FIG. 1. 2 is a flow chart illustrating one implementation method of the present invention. It is sectional drawing which shows the conventional mold structure using a 2 division | segmentation sleeve. It is sectional drawing which shows the conventional mold structure using a 4-partition carbon plate.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show an embodiment according to the present invention of the structure of a continuous casting mold having a rectangular cross section.

  The water-cooled protector 11 made of copper or a copper alloy has a rectangular cross section, includes a cooling water passage 12 therein, and a heat transfer sheet 14 made of a graphite sheet having compression restoring property on the inner wall on the long side of the water-cooled protector 11; A U-shaped sleeve 13 divided into two on the short side is provided.

  The two-divided sleeve 13 is made of carbon, graphite, or the like, and the size when the sleeve is assembled together is made smaller than the inner wall of the water-cooled protector 11. Accordingly, the heat transfer sheet 14 is allowed to enter between the inner wall of the long-side water-cooled protector 11 and the two-divided sleeve 13, and the two-divided sleeve 13 can be easily inserted into the water-cooled protector 11.

  A marginal gap 15 is formed on the short side to prevent the sleeve 13 that thermally expands during the casting operation from colliding with the water-cooled protector 11.

  The dimension of the two-divided sleeve 13 in this embodiment is such that the dimensional difference from the inner wall of the water-cooled protector 11 when the sleeves are assembled together is 1.0 mm to 3.0 mm on the long side and the above on the short side. The length of the long side of the two-divided sleeve 13 is 0.5% or more and 1.0% or less.

  Further, between the short side of the two-divided sleeve 13, the two-divided sleeve 13 and the heat transfer sheet 14 are stretched toward the long side of the water-cooled protector 11, and the two-divided sleeve 13 is compressed while the heat-transfer sheet 14 is compressed. The widening means 18 fixed to the 11 inner wall is provided. The widening means 18 will be described in detail with reference to FIGS.

  The widening means 18 includes a key groove 16 provided between the two-sided sleeves 13 on the short side and a wedge 17 inserted into the key groove.

  The key groove 16 is formed so as to cut out the outer periphery of the abutting portion between the two-sided sleeves 13 on the short side, and the depth of the key groove 16 determines the rigidity of the thinned portion 19 formed after the notch. Considering this, the thickness of the two-piece sleeve 13 is set to 50% or more and 70% or less. That is, the thickness of the thinned portion 19 provided between the two-sided sleeve 13 on the short side is set to be 30% or more and 50% or less of the thickness of the two-sided sleeve 13.

  Further, the key groove 16 is configured such that when the heat transfer sheet 14 is compressed to half, no gap is formed between the key groove 16 and the wedge 17, that is, the heat transfer sheet 14 can be compressed more than half.

  The wedge 17 is composed of a pair of carbon gradient keys. The dimensions of the wedge 17 are larger than the width of the keyway 16 at room temperature when the taper faces are reversed and the taper surfaces are arranged face to face. To be. Here, the width of the key groove 16 refers to the width of the space formed by the notch of the two-divided sleeve 13 when the two-divided sleeve 13 is disposed in the water-cooled protector 11 via the heat transfer sheet 14.

  Further, the wedge 17 seals leakage of the molten metal from a minute gap formed between the butted portions of the two-divided sleeve 13 when the two-divided sleeve 13 is fixed to the inner wall of the water-cooled protector 11. Is done.

  The heat transfer sheet 14 compressed by the widening means 18 has compression restoring properties, absorbs unevenness and roughness formed on the inner wall of the water-cooled protector 11, and is in close contact with the two-divided sleeve 13 and the water-cooled protector 11. Is.

  In this continuous casting mold, the two-divided sleeve 13 and the water-cooled protector 11 are brought into close contact with each other via the heat transfer sheet 14, and the cooling unevenness of the mold can be improved.

  As a result, the cooling uniformity required in continuous casting of copper alloys can be strictly controlled, improving the quality of the ingot, and reducing serious product defects such as fogging and peeling in the processing process. it can.

  Further, deformation and wear due to oxidation and thermal stress of the inner wall of the water-cooled protector 11 are reduced, which can contribute to extending the life of the mold and reducing the equipment cost.

  Next, a construction method for inserting a new two-piece sleeve 13 during maintenance of the continuous casting mold according to the present invention will be described with reference to FIG.

  First, in step 31, correction work such as grinding is appropriately performed on the inner wall of the water-cooled protector 11 in which corrosion due to thermal deformation or oxidation occurs during the replacement work of the two-divided sleeve 13.

  In step 32, the heat-transfer sheet | seat 14 which absorbs an unevenness | corrugation at the time of compression is distribute | arranged to the water-cooling protector 11 long side inner wall. Thereby, in addition to the effect mentioned above, the effect of raising the said plane accuracy with respect to the deterioration of the plane accuracy of the water-cooled protector 11 at the time of correction work is also acquired.

  Subsequently, in Step 33, the two-divided sleeve is inserted into the water-cooled protector 11. Since the dimension when the two-divided sleeves 13 are assembled together is smaller than the inner diameter of the water-cooled protector 11, the heat transfer sheet 14 and the two-divided sleeve 13 can be easily inserted into the water-cooled protector 11. Since the heat transfer sheet 14 absorbs some pressure when the wedge 17 is inserted, it is not necessary to make the size of the two-piece sleeve 13 smaller than necessary.

  Further, in step 34, the inner surface of the two-divided sleeve 13 is stretched by various methods such as a hydraulic jack, air jack, screw jack, etc., and the heat transfer sheet 14 is compressed and held on the inner wall of the water-cooled protector 11 while being compressed.

  While maintaining this stretched state, in step 35, one wedge 17 made of a carbon gradient key is inserted into the key groove 16 provided on the short side of the two-divided sleeve 13.

  Next, as step 36, another wedge 17 is driven into the keyway 16. The design dimension of the key groove 16 is such that no gap is formed even when the thickness of the heat transfer sheet 14 is compressed to half, and the gradient key with the taper faces reversed and the taper surfaces facing each other has a pair of thicknesses. It is made larger than the dimension of the keyway 16.

  As a result, the tip of the wedge 17 to be inserted later becomes tight before reaching the lower end position of the two-divided sleeve 13. When the two-divided sleeve 13 is crimped and fixed to the inner surface of the water-cooled protector 11, the rear end of the wedge 17 travels above the two-divided sleeve 13. Adjust the height.

  In the construction method of the present invention, the two-divided sleeve 13 is held by the water-cooled protector 11 with a jack or the like while compressing the heat transfer sheet 14, and the two-divided sleeve 13 can be positioned and fixed while maintaining the compressed state.

  For this reason, the two-divided sleeve 13 and the water-cooled protector 11 are in uniform contact with each other via the heat transfer sheet 14 to obtain uniform cooling of the ingot, resulting in poor quality of the ingot, fogging and peeling in the processing step. It is possible to reduce serious product defects such as.

  In addition, since the number of parts constituting the mold is small, the two-divided sleeve 13 can be easily inserted into the water-cooled protector 11, and the two-divided sleeve 13 can be easily positioned and held with a jack or the like, so that the work efficiency during maintenance can be improved. it can.

11 Water-cooled protector 13 2 split sleeve 14 Heat transfer sheet 18 Widening means

Claims (7)

  In a continuous casting mold in which a U-shaped sleeve divided into two on the short side is arranged on the inner wall of a water-cooled protector having a rectangular cross section, a heat transfer sheet having a compression restoring property is provided on the inner wall on the long side of the water-cooled protector A continuous casting mold characterized in that a widening means for pressing both sleeves against the long side inner wall of the water-cooled protector is provided between the two divided sleeves on the short side through the heat transfer sheet.   The continuous casting mold according to claim 1, wherein the heat transfer sheet comprises a graphite sheet.   The continuous casting mold according to claim 1 or 2, wherein the widening means includes a key groove provided on the short side of the two-divided sleeve and a wedge that is inserted into the key groove to widen the two-divided sleeve.   The continuous casting mold according to claim 3, wherein the keyway has a depth of 50% to 70% of the thickness of the two-piece sleeve.   When the two divided sleeves are assembled together, the difference in dimension between the outer surface of the two divided sleeves and the inner wall of the water-cooled protector is 1.0 mm to 3.0 mm on the long side, and the long side of the two divided sleeves on the short side. The casting mold for continuous casting according to any one of claims 1 to 4, wherein the length is 0.5% or more and 1.0% or less of the length. A water-cooled protector having a rectangular cross section;
Two pairs of heat transfer sheets provided on the inner surface of the wide surface of the water-cooled protector;
Two pairs of U-shaped sleeves provided so as to be in contact with the inside of the heat transfer sheet and having release ends on the narrow surface side of the protector;
A keyway formed at the end of the U-shaped sleeve on the water cooling protector side;
A mold for a continuous casting machine, comprising two wedges whose total length of the short side is wider than the width of the keyway when engaged.   In the construction method of a continuous casting mold in which a U-shaped sleeve divided into two on the short side is arranged on the inner wall of a water-cooled protector having a rectangular cross section, the heat transfer sheet having compression / restoration property on the inner wall of the long-side of the water-cooled protector A widening means is provided between the two split sleeves on the short side, and both sleeves are pressed against the inner wall on the long side of the water-cooled protector via the heat transfer sheet. A method for constructing a continuous casting mold, wherein the inner wall of the water-cooled protector is pressed through the heat transfer sheet.

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