Processing Technology of Copper Tube with Diversion Hole Curved Crystallizer

Abstract

The invention discloses a processing technology for a copper tube of a guide hole type arc crystallizer, and relates to the technical field of crystallizer copper tube processing, comprising: preparing a straight square blank of the copper tube: drawing the copper tube blank into the straight square blank of the copper tube through a straight core rod and a square die on a horizontal hydraulic press; processing the guide hole: pre-drilling a through hole on the straight square blank that is 12% larger than the diameter of the guide hole in the drawing; filling the guide hole: plugging one end of the processed guide hole with a copper plug, and pouring filler into the other end to fill it; copper tube extrusion molding: inserting an arc core rod into the straight square blank, and under the drive of the horizontal hydraulic press, making the copper tube pass through a die with the same cross-sectional size as the copper tube; cleaning and repairing the guide hole: cleaning the filler in the guide hole and then repairing the guide hole; sawing and milling processing: trimming the total length of the copper tube, sawing the two ends of the crystallizer copper tube, and processing a card slot. The present invention can improve the processing quality of the guide hole of the arc crystallizer copper tube.

Description

Technical Field

[0001] The invention relates to the technical field of crystallizer copper tube processing, in particular to a processing technology of a guide hole type arc-shaped crystallizer copper tube. Background Art

[0002] The mold copper tube is the core component of the steel continuous casting machine. With the continuous development of steel continuous casting technology, in order to improve steel production efficiency and steel quality, in recent years, the continuous casting mold equipment and spare parts market has added many improved types of mold copper tube structures, such as copper tubes with finely processed outer surfaces, grooved copper tubes, and guide hole copper tubes.

[0003] The perforated mold copper tube is cooled by circular holes spaced longitudinally (lengthwise) along the tube wall. During operation, cooling water at a pressure of approximately 1 MPa flows through the perforated holes, transferring heat along the entire circumference of the holes. This results in higher cooling efficiency than conventional tubular mold copper tubes. Furthermore, because the cooling water pressure exerts uniform pressure in all directions around the perforated holes, the pressures in all directions cancel each other out, effectively creating zero pressure on the tube wall. In contrast, the cooling water pressure of other mold copper tubes is unidirectional, causing the tube wall to deform toward the tube's interior, leading to tapering errors. Perforated copper tubes eliminate deformation caused by cooling water pressure during operation, thereby better maintaining the accuracy of the tube during operation.

[0004] In the prior art, when processing the guide holes of the crystallizer copper tube, there are problems of poor processing accuracy and large roundness error of the guide holes. In order to reduce the deformation of the guide holes in the subsequent stretching forming process of the copper tube, the prior art will fill the guide holes before stretching. However, when filling the guide holes in the prior art, there are problems of improving the shrinkage and flattening effect of the guide holes or the subsequent filling is difficult to clean. Summary of the Invention

[0005] In response to the above technical problems, the present invention proposes a processing technology for a guide hole type curved crystallizer copper tube, comprising the following steps:

[0006] S1. Preparation of a copper tube blank: Drawing a copper tube blank with a half-bottom structure into a copper tube blank on a horizontal hydraulic press through a straight core rod and a square die.

[0007] S2. Processing of diversion holes: When processing diversion holes: pre-drill a through hole on the rectangular blank that is 12% larger than the diameter design size of the hole in the drawing; place the rectangular blank on a high-precision special deep hole drilling and boring machine with a guide device for processing, and drill the holes at both ends according to the coordinate position to reduce the position error when processing the diversion hole and improve the processing accuracy.

[0008] S3. Filling the guide hole: Before the final forming of the copper tube, the guide hole processed in S2 is blocked with a copper plug at one end, and filler is poured from the other end to fill it up, so as to reduce the deformation of the guide hole and the transmission of extrusion force during the subsequent extrusion forming process of the copper tube, and ensure that the inner cavity is close to the mold.

[0009] S4. Copper tube extrusion molding: Use an arc-shaped core rod that is consistent with the geometric dimensions and curvature parameters of the inner cavity of the crystallizer copper tube to penetrate into the rectangular blank, and then, driven by a horizontal hydraulic press, make the copper tube pass through a concave die that is consistent with the outer cross-sectional dimensions of the copper tube, thereby completing the extrusion molding of the arc-shaped crystallizer copper tube.

[0010] S5. Clean and repair the guide hole: After extrusion molding, clean the filler in the guide hole; after cleaning, repair the guide hole to ensure that the size and roundness of the guide hole meet the requirements of the drawing.

[0011] S6. Sawing and milling processing: trim the total length of the copper tube according to the requirements of the drawing, saw the two ends of the copper tube of the guide hole type curved crystallizer, and process the pallet groove to complete the processing of the copper tube of the guide hole type curved crystallizer.

[0012] Furthermore, the inner cavity size of the rectangular blank is 6-8 mm larger than the inner cavity of the finished copper tube to ensure the smooth insertion of the subsequent arc core rod; the wall thickness of the rectangular blank is made according to a deformation rate of 18%, that is: the wall thickness of the rectangular blank X = S / (1-18%): where: S is the theoretical wall thickness of the finished product; the rectangular blank is in an annealed state.

[0013] Furthermore, the processing of the diversion holes belongs to the category of fine deep hole processing, which requires ensuring the spacing size of the holes, as well as the processing direction of the holes and the position tolerance between the inner cavity of the copper tube and the holes; when processing the diversion holes: the rectangular blank is placed on a high-precision special deep hole drilling and boring machine with a guide device for processing, and the diversion holes are drilled by drilling at both ends according to the coordinate position to reduce the position error when drilling the diversion holes and improve the processing accuracy.

[0014] Furthermore, a tin-bismuth alloy is selected as a filler to reduce the ovality error of the guide hole. During filling, all holes at one end of the copper tube with a bottom are plugged and hammered tight with a conical copper plug. The copper tube is preheated to 130°C and placed with the bottom end facing downward. A tin-bismuth alloy block is heated to 160-180°C in a crucible, and molten tin-bismuth alloy liquid is poured into the guide hole to fill it. After the copper tube cools to room temperature, it is formed and stretched to minimize deformation of the guide hole and ensure that the inner cavity of the copper tube fits well with the surface of the core rod.

[0015] Furthermore, during the copper tube extrusion forming process, the arc-shaped core rod is connected to the slider of the horizontal hydraulic press through a pin shaft through a hole at one end, and then the straight square blank is put on the arc-shaped core rod, and the other end of the arc-shaped core rod is pushed to the bottom of the inner cavity of the straight square blank; the die is placed against the die base plate on the hollow beam of the horizontal hydraulic press, and the arc-shaped core rod moves under the drive of the slider of the horizontal hydraulic press, thereby driving the straight square blank into the die. Since the straight square blank in the annealed state has good plasticity and ductility, the straight square blank is When passing through the die, under the extrusion of the die, the inner cavity of the straight square blank gradually adheres to the surface of the arc core rod, and extends along the arc core rod. At the same time, under the action of the extrusion resistance, the position of the die changes with the position of the arc core rod, that is: the angle of the die swings along the arc surface on the back, and the upper and lower positions slide along the die base plate; when the straight square blank passes through the die as a whole, the extrusion molding of the copper tube is completed, and then a guide hole type arc crystallizer copper tube with an inner cavity and an outer shape that meet the requirements is extruded.

[0016] Furthermore, when cleaning and repairing the diversion hole: a steel receiving tray is placed at the bottom of the well-type heat treatment furnace, and the bottom end of the extruded copper tube is placed upright on the receiving tray; the copper tube is heated to 150°C, and the molten tin-bismuth alloy flows into the steel receiving tray for recovery; a ball-end rotary file consistent with the design dimensions of the drawing is used, and an extension rod is used. The length of the extension rod is 60% of the total length of the copper tube, and a diameter of Φ5 cold-drawn steel bar is used, which is butt-welded to the handle of the ball-end rotary file; a hand drill or a horizontal milling machine is used as the power, and the ball-end rotary file head is used to expand and repair the diversion hole from both ends, and ensure that the sum of the expansion depths at both ends is not less than the total length of the copper tube; since the ball-end rotary file is guided by the hole, the extension rod used is elastic and bends with the hole, thereby achieving expansion of the elliptical diversion hole, ensuring that the size and roundness of the diversion hole meet the requirements of the drawing.

[0017] Furthermore, the two ends of the copper tube of the guide hole type curved crystallizer are sawed, leaving a processing allowance of 5-10mm at each end, the total length of the copper tube is trimmed, and the card groove is processed to complete the processing of the copper tube of the guide hole type curved crystallizer.

[0018] Furthermore, the material of the crystallizer copper tube is selected from chromium-zirconium copper or silver-copper; when chromium-zirconium copper is selected, the composition ratio by weight is: Cr: 0.9%, Zr: 0.2%, and the rest is Cu; when silver-copper is selected, the composition ratio by weight is: Cu+Ag≥99.9%, Ag: 0.08-0.12%; P: 0.004-0.012%.

[0019] The beneficial effects of the present invention compared with the prior art are as follows: (1) the present invention can ensure that the long axis of the cross section of the elliptical guide hole after extrusion molding is consistent with the size of the finished hole, and can also ensure that the processing allowance during subsequent hole expansion is minimized, reduce the position error when drilling the guide hole, and improve the processing accuracy; (2) the present invention uses tin-bismuth alloy, which has a low melting point and moderate hardness after cooling, and can well ensure the support of the guide hole and extension with the hole during subsequent cold extrusion, facilitate injection operation and subsequent cleaning, is non-toxic, and improves the shrinkage and flattening of the guide hole; (3) the present invention uses tin-bismuth alloy, which has a low melting point and moderate hardness after cooling, and can well ensure the support of the guide hole and extension with the hole during subsequent cold extrusion, facilitate injection operation and subsequent cleaning, is non-toxic, and improves the shrinkage and flattening of the guide hole; (3) The copper tube extrusion molding process of the invention can extrude a guide hole type curved crystallizer copper tube with an inner cavity and an outer shape that meet the requirements; (4) In the prior art, when cleaning and repairing the guide hole, it is impossible to ensure that the ellipticity requirements of the hole are met. The only way is to enlarge the size of the pre-drilled guide hole to ensure that the cross-sectional area of ​​the finished hole is equivalent to the design to meet the performance requirements, but it is impossible to ensure that the size of the guide hole meets the requirements of the drawing. Through the secondary processing of the guide hole using a spherical rotary file with an extension rod of the present invention, a product that meets the requirements of the drawing can be processed, solving the problem of the hole shape not being consistent with the drawing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the extrusion molding of the copper tube of the guide hole crystallizer of the present invention.

[0021] Figure 2 This is a front view of the guide hole type crystallizer copper tube of the present invention.

[0022] Figure 3 For the present invention Figure 2 Cross-sectional view along the AA direction.

[0023] Figure 4 Schematic diagram comparing the ideal and actual contours of the guide holes in the crystallizer copper tube after extrusion molding of the present invention.

[0024] Figure 5 It is a schematic structural diagram of the ball-end rotary file and the extension rod of the present invention.

[0025] Figure 6 Schematic diagram of the rectangular blank structure of the crystallizer copper tube of the present invention Figure 1 .

[0026] Figure 7 Schematic diagram of the rectangular blank structure of the crystallizer copper tube of the present invention Figure 2 .

[0027] Figure 8 Schematic diagram of the rectangular blank of the crystallizer copper tube after processing the guide hole of the present invention Figure 1 .

[0028] Figure 9 Schematic diagram of the rectangular blank of the crystallizer copper tube after processing the guide hole of the present invention Figure 2 .

[0029] Figure numbers: 1-arc core rod; 2-filler; 3-rectangular blank; 4-die; 5-copper plug; 6-ideal contour line of diversion hole; 7-actual contour line of diversion hole; 8-extension rod; 9-ball-end rotary file handle; 10-ball-end rotary file head. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0031] The present invention proposes a processing technology for a guide hole type curved crystallizer copper tube, comprising the following steps:

[0032] S1. Preparation of a straight square blank 3 for a copper tube: The copper tube blank is drawn into a straight square blank 3 on a horizontal hydraulic press through a straight core rod and a square die. The copper tube blank needs to be made into a structure with a half bottom, and the bottom serves as a process head. The process head is used to press against the end of the straight core rod to limit the movement of the copper tube blank and the straight core rod, so as to achieve relative movement between the square die and the copper tube blank during extrusion molding; the inner cavity size of the straight square blank 3 is 6-8mm larger than the inner cavity of the copper tube finished product to ensure the smooth insertion of the subsequent curved core rod 1; the wall thickness is made according to a deformation rate of 18%, that is, the wall thickness of the straight square blank X = S / (1-18%): where: S is the theoretical wall thickness of the finished product, and the straight square blank 3 is required to be in an annealed state.

[0033] S2. Processing of guide holes: Since the finished crystallizer copper tube is arc-shaped, the path direction of the guide hole is consistent with the arc shape of the copper tube. The arc-shaped deep hole cannot be directly processed by mechanical processing methods, and can only be pre-processed in the straight tube stage of the copper tube as a rectangular blank 3. The rectangular blank 3 needs to undergo a stretching and over-molding process during the subsequent stretching forming process. It is necessary to ensure that the rectangular blank 3 fits the arc-shaped core rod 1 and also to have a stretching and lengthening process. As a result, the guide hole is stretched and shrunk, and also has a "flattened" shape change; so the size of the processed guide hole should be larger than the aperture specified in the finished product design; after experimental comparison, the guide hole processing needs to pre-drill a through hole about 12% larger than the diameter specified in the drawing in the straight tube stage of the rectangular blank 3. This can ensure that the long axis of the elliptical guide hole cross section after extrusion is consistent with the size of the finished hole, and can also ensure that the processing allowance during subsequent hole expansion is minimized. The machining of diversion holes is a type of fine deep hole machining, requiring guaranteed spacing, consistent machining direction, and positional tolerances within the copper tube cavity, as well as between holes. The rectangular blank 3 is placed on a high-precision, specialized deep-hole drilling and boring machine equipped with a guide device. Drilling is performed using a double-drilling method based on coordinate positions to minimize positional errors during drilling of the diversion holes and improve machining accuracy.

[0034] S3. Filling the guide holes: To reduce the deformation of the guide holes during the subsequent stretching process, the guide holes need to be filled with filler 2 before the copper tube is extruded. Common materials used to fill the guide holes in the past include river sand, fine steel balls, and plastic. However, each of these methods has its drawbacks. For example, while river sand and fine steel balls have some effect on improving the oval shape of the holes, they are difficult to clean. While pouring molten plastic into the holes, heating and melting them after extrusion and then removing them is easier to clean, due to the plastic's low hardness, it is not ideal for improving the shrinkage and flattening of the holes. Since copper begins to recrystallize at temperatures above 200°C, when using filler materials that flow out through the melting method, the required heating temperature must not exceed 200°C to avoid affecting the hardness and other properties of the copper tube substrate. Tin-bismuth alloy (42% tin, 58% bismuth, melting point 138°C) is selected for its low melting point and moderate hardness after cooling. This ensures excellent support for the guide hole during subsequent cold extrusion and allows for easy injection and subsequent removal. It is non-toxic and significantly improves the shrinkage and flattening of the guide hole compared to the aforementioned materials. Therefore, tin-bismuth alloy is the preferred filler 2. During filling, all holes at one end of the copper tube with a bottom are first plugged and hammered shut with a tapered copper plug 5 approximately 15 mm long. The copper tube is preheated to approximately 130°C (e.g., by baking) and placed with the bottom end facing downward. An appropriate amount of tin-bismuth alloy ingot is then heated in a crucible to 160-180°C. Molten tin-bismuth alloy is then poured into the holes to fill them completely. After cooling to room temperature, extrusion molding is performed to minimize deformation of the guide hole and ensure surface conformity between the copper tube's inner cavity and the curved core rod 3. Filling with tin-bismuth alloy effectively improves the hole's ellipticity error.

[0035] S4. Copper tube extrusion molding: After the filler is filled in the copper tube guide hole, the copper tube is extruded into a curved square copper tube at room temperature through the curved core rod 1 and the die 4 on a horizontal hydraulic press at one time, with the inner cavity matching the curved core rod 1 and the outer cross-section meeting the outer dimensions of the copper tube.

[0036] During the extrusion process, the arc-shaped core rod 1 is connected to the slider of the horizontal hydraulic press through the hole at the left end via a pin, and then the straight square blank 3 is put on the arc-shaped core rod 1, and the right end of the arc-shaped core rod 1 should be against the bottom of the inner cavity of the straight square blank 3. The die 4 is abutted against the die base plate on the hollow beam of the hydraulic press. The arc-shaped core rod 1 is driven by the slider of the hydraulic press to move horizontally to the right, driving the straight square blank 3 into the die 4. Since the straight square blank 3 in the annealed state has good plasticity and ductility, when the straight square blank 3 passes through the die 4, under the extrusion of the die 4, the inner cavity of the straight square blank 3 gradually adheres to the surface of the arc-shaped core rod 1, and also extends to the left along the arc-shaped core rod 1. At the same time, under the action of the extrusion resistance, the position of the die 4 will change with the position of the arc-shaped core rod 1, that is, the angle of the die 4 swings along the curved surface of the back, and the up and down positions can slide along the die base plate. Until the straight square blank 3 material as a whole passes through the die 4, the extrusion forming process of the copper tube is completed. Through the above extrusion forming process, a guide hole type curved crystallizer copper tube with an inner cavity and an outer shape that meets the requirements can be extruded.

[0037] During the extrusion process, since the arc-shaped core rod 1 is hinged by a pin, as the extrusion force changes, the right end of the arc-shaped core rod 1 can swing in a small range around the pin hole at the left end. Although the die 4 is limited in the horizontal direction by the die base on the hydraulic press beam, the die 4 can change with the tensile force and the arc angle. Through the arc structure on both sides of the back of the die 4, it can roll through the back arc structure or slide on the die base plate as the force changes during the copper tube extrusion process. In this way, through this extrusion and stretching process, the inner cavity of the copper tube is consistent with the geometric parameters such as size, curvature, and taper of the arc-shaped core rod 1, and the cross-sectional size is consistent with the die 4.

[0038] S5. Clean and repair the guide holes: Place a steel receiving tray at the bottom of the well-type heat treatment furnace, and stand the extruded copper tube strip with the bottom end facing upwards on the receiving tray. Heat the copper tube to about 150°C, and the molten tin-bismuth alloy flows into the tray for recovery. After the guide holes are filled with tin-bismuth alloy and the copper tube is extruded and drawn, the guide holes will have an obvious "flattened" elliptical phenomenon under the combined action of the extrusion and stretching forces. Usually, the long axis of the elliptical guide hole will be reduced by about 12%, and the short axis will be reduced by about 20%. The ideal contour line 6 of the guide hole and the actual contour line 7 of the guide hole are as shown in the figure. Figure 4 As shown, a ball-end rotary file consistent with the design drawing is used in conjunction with an extension rod 8. The extension rod 8 is 60% of the total length of the copper tube and is made of Φ5 diameter cold-drawn steel bar. It is butt-welded to the ball-end rotary file handle 9. Using a hand drill or horizontal milling machine, the ball-end rotary file head 10 is used to ream the diversion hole from both ends. The combined depth of the reaming at both ends is ensured to be no less than the total length of the copper tube. Because the ball-end rotary file can follow the hole, the extension rod 8 must be flexible and able to bend with the hole. This allows for the reaming of elliptical diversion holes, ensuring that the hole size and roundness meet the design drawing requirements.

[0039] S6. Sawing and milling: According to the requirements of the drawings, when milling the copper tube: saw the two ends of the copper tube of the guide hole type curved crystallizer, leaving a processing allowance of 5-10mm at each end, trim the total length of the copper tube according to the requirements of the drawings, process the pallet groove, etc., and then complete the processing of the copper tube of the guide hole type curved crystallizer.

[0040] like Figures 1-9 As shown, the present invention provides two kinds of processing technology of guide hole type curved crystallizer copper tube:

[0041] Example 1: A guide hole curved crystallizer copper tube made of chromium zirconium copper was manufactured, with inner cavity dimensions of width 165 mm x height 163 mm x length 1000 mm, an arc radius R of 10000 mm, and a wall thickness of 30 mm. The diameter of the guide hole was φ10, and the guide hole curved crystallizer copper tube made of chromium zirconium copper was provided with a total of 36 guide holes, with 9 guide holes provided on each surface of the crystallizer copper tube. The processing flow was as follows:

[0042] A rectangular blank 3 of a copper tube made of chromium-zirconium copper is prepared: the material ratio (weight %) of the chromium-zirconium copper is: Cr: 0.9%, Zr: 0.2%, and the rest is Cu. The inner cavity size of the rectangular blank 3 is width 171 mm x height 169 mm, and the wall thickness is: 30 / (1-18%) ≈ 36.5 mm. The effective material length of the rectangular blank 3 is approximately 850 mm, and the total length including the bottom is 890 mm. The copper tube blank made of chromium-zirconium copper is drawn into the rectangular blank 3 on a horizontal hydraulic press through a straight core rod and a square die. The copper tube blank needs to be made into a structure with a half bottom, and the bottom serves as a process head. The process head is used to support the end of the straight core rod to limit the movement of the copper tube blank and the straight core rod, so as to achieve relative movement between the square die and the copper tube blank during extrusion molding.

[0043] Processing of guide holes: The diameter of the guide hole of the finished copper tube of the crystallizer is φ10, and the diameter of the pre-drilled guide hole is φ11.2. It needs to penetrate the entire length of the copper tube blank of 890mm. The guide hole is a fine deep hole processing, which requires high processing precision and the internal deflection error of the entire length is not more than 0.5mm; in order to ensure the processing accuracy of the guide hole, ensure the hole spacing size, the position tolerance between the hole and the inner cavity of the copper tube, and the hole and the hole, the guide hole must be processed on a high-precision special deep hole boring machine with a guide device, and the drilling method of both ends is used to reduce the processing error of the deep hole and improve the processing accuracy.

[0044] Filling the guide holes: All the guide holes processed above are plugged at the right end with a tapered copper plug 5 with a small end diameter of φ11 and a length of approximately 15 mm, and hammered tightly. After completion, the right end is raised downward and the guide holes are filled with a tin-bismuth alloy solution (tin content 42%, bismuth content 58%, melting point 138°C). After cooling to room temperature, extrusion molding is performed; the guide holes are filled with lead-tin alloy and then extruded to reduce the degree of deformation of the guide holes and ensure the mold effect of the inner cavity and the curved core rod 1.

[0045] Copper tube extrusion: At room temperature, a curved core rod (1) with cross-sectional dimensions (width 165mm x height 163mm x length 1500mm) and an arc radius of R10000mm is hinged to the die base of the horizontal hydraulic press's slider. A rectangular blank (3) with a guide hole filled with tin-bismuth alloy is then placed over the curved core rod (1). The die (4) is suspended against the template of the hydraulic press's front beam. The curved core rod (1) is operated and the position of the die (4) is adjusted to allow the curved core rod (1) and the rectangular blank (3) to pass through the die. After the copper tube is extruded, the material is withdrawn.

[0046] Cleaning and repairing the diversion holes: Place a steel contact plate in the bottom of a pit heat treatment furnace, support the copper tube with its bottom side facing upwards, and place it on top of the plate. The copper tube is heated to approximately 150°C in the pit heat treatment furnace, causing the tin-bismuth alloy filling the diversion holes to melt and flow out. After the copper tube is extruded, the diversion holes, filled with tin-bismuth alloy, undergo a noticeable "flattening" effect due to the extrusion force. Typically, the major axis of the elliptical diversion hole is reduced by approximately 12% and the minor axis by approximately 20%. The pre-drilled diameter of the diversion hole is φ11.2mm. After extrusion, the major axis is shortened to approximately 10mm and the minor axis to approximately 8.9mm. To ensure the dimensional accuracy of the hole, a standard φ10 diameter ball-end rotary file with a φ6 diameter shank is used. This file is then connected to a φ5 diameter cold-drawn steel extension rod 8, which is 600mm long and butt-welded to the ball-end rotary file shank 9. The φ5 cold-drawn steel bar used not only provides the torque required to expand the extension rod 8, but also ensures the elastic deformation required by the arc path of the hole. Using a hand drill with a power of at least 500W, the end of the extension rod 8 is clamped with a drill chuck, inserted into the diversion hole, and the drill is started. The ball-end rotary file 10 is then used to complete the diversion hole expansion repair. After the repair, the diversion hole's dimensions and roundness meet the drawing requirements.

[0047] Sawing and milling processing: According to the requirements of the drawings, saw the heads of both ends of the copper tube of the guide hole type curved crystallizer, leaving a processing allowance of 5-10mm at each end, and then trim the total length of the copper tube according to the requirements of the drawings, process the pallet groove, etc., and then complete the processing of the copper tube of the guide hole type curved crystallizer. Example 2:

[0048] The silver-copper diversion hole curved crystallizer copper tube is made of silver-copper, with inner cavity dimensions of 170mm width, 168mm height, and 1000mm length, arc radius R8000mm, wall thickness 25mm, and diversion hole diameter φ12. The silver-copper diversion hole curved crystallizer copper tube has a total of 32 diversion holes, and each surface of the crystallizer copper tube has 8 diversion holes. The processing steps are as follows:

[0049] A rectangular blank 3 made of silver-copper copper tube is prepared: the material ratio of silver-copper (weight %) is: Cu+Ag≥99.9%, Ag: 0.08-0.12%; P: 0.004-0.012%; the inner cavity size of the rectangular blank 3 is width 176mm×height 174mm, and the wall thickness is: 25 / (1-18%)≈30.5mm; the effective material length is about 850mm, and the total length including the bottom is 880mm; the copper tube blank made of silver-copper is drawn into the rectangular blank 3 on a horizontal hydraulic press through a straight core rod and a square die. The copper tube blank needs to be made into a structure with a half bottom, and the bottom is used as a process head. The process head is used to support the end of the straight core rod to limit the movement of the copper tube blank and the straight core rod, so as to achieve relative movement between the square die and the copper tube blank during extrusion molding.

[0050] Processing of diversion holes: The diameter of the finished diversion hole of the copper tube is φ12, and the diameter of the pre-drilled diversion hole is Φ13.4. It needs to penetrate the entire length of the copper tube blank of 880mm. The diversion hole is a fine deep hole processing, which requires high processing precision and the internal deflection error of the entire length is not more than 0.5mm; in order to ensure the processing accuracy of the diversion hole, ensure the hole spacing size, and the position tolerance between the hole and the inner cavity of the copper tube and between the holes, the diversion hole must be processed on a high-precision special deep hole boring machine with a guide device, and the drilling method of both ends is used to reduce the processing error of the diversion hole and improve the processing accuracy.

[0051] Filling the guide holes: All the guide holes processed above are plugged tightly at the right end with a tapered copper plug 5 with a small end diameter of φ13 and a length of about 15 mm. After completion, the right end is turned downward and a tin-bismuth alloy solution (tin content 42%, bismuth content 58%, melting point 138 degrees) is poured into it. After cooling to room temperature, it is extruded and formed.

[0052] Copper tube extrusion: At room temperature, a curved core rod (1) with cross-sectional dimensions of 170mm (width) x 168mm (height) x 1500mm (length) and an arc radius of R8000mm is hinged to the die base of the horizontal hydraulic press's slider. A rectangular blank (3) with a guide hole filled with tin-bismuth alloy is then placed over the curved core rod. The die (4) is suspended against the template of the hydraulic press's front beam. The curved core rod (1) is operated and the position of the die (4) is adjusted to allow the curved core rod (1) and the rectangular blank (3) to pass through the die. After the copper tube extrusion is complete, the material is withdrawn.

[0053] Cleaning and repairing the diversion holes: Place a steel receiving tray in the bottom of the pit heat treatment furnace, support the copper tube with its bottom side facing upwards and place it on top of the contact tray. The pit heat treatment furnace heats the copper tube to approximately 150°C, causing the tin-bismuth alloy filling in the diversion holes to melt and flow out. After the copper tube is extruded, the diversion holes will be noticeably "flattened" into an elliptical shape due to the extrusion force. Typically, the major axis of the elliptical diversion hole is reduced by approximately 12%, and the minor axis is reduced by approximately 20%. The pre-drilled diameter of the diversion hole is φ13.4. After extrusion, the major axis is shortened to approximately 12mm, and the minor axis is approximately 10.7mm. To ensure the dimensional accuracy of the diversion hole, a standard φ12 diameter ball-end rotary file with a φ6 shank is used. It is connected to a φ5 diameter cold-drawn steel bar extension rod 8. The extension rod 8 is 600mm long and is butt-welded to the ball-end rotary file handle 9. Using φ5 cold-drawn steel bars ensures both the torque required to expand the extension rod 8 and the elastic deformation required to maintain the arc-shaped path of the hole. Using a hand drill with a power of at least 500W, clamping the end of the extension rod 8 with a drill chuck, and using a ball-end rotary file 10, the diversion hole is reamed and repaired. This ensures that the diversion hole's dimensions and roundness meet the drawing requirements.

[0054] Sawing and milling processing: According to the requirements of the drawings, saw the heads of both ends of the copper tube of the guide hole type curved crystallizer, leaving a processing allowance of 5-10mm at each end, and then trim the total length of the copper tube according to the requirements of the drawings, process the pallet groove, etc., and then complete the processing of the copper tube of the guide hole type curved crystallizer.

Claims

1. The processing technology of the guide hole type arc crystallizer copper tube is characterized in that: The following steps are involved: S1. Preparation of a copper tube blank (3): Drawing the copper tube blank with a half-bottom structure into a copper tube blank (3) on a horizontal hydraulic press through a straight core rod and a square die; S2. Processing the diversion hole: When processing the diversion hole: pre-drill a through hole on the rectangular blank (3) that is 12% larger than the diameter design size of the hole in the drawing; place the rectangular blank (3) on a high-precision special deep hole drilling and boring machine with a guide device for processing, and drill the hole using a two-end drilling method according to the coordinate position to reduce the position error when processing the diversion hole and improve the processing accuracy; S3, filling the guide hole: before the copper tube is finally formed, the guide hole processed in S2 is first blocked with a copper plug (5) at one end, and the filler (2) is poured from the other end to fill it up, so as to reduce the deformation of the guide hole and the transmission of the extrusion force during the subsequent extrusion molding of the copper tube, and ensure that the inner cavity is mold-fitted; S4, copper tube extrusion molding: use an arc-shaped core rod (1) that is consistent with the geometric dimensions and curvature parameters of the inner cavity of the crystallizer copper tube to penetrate into the rectangular blank (3), and then, driven by a horizontal hydraulic press, make the copper tube pass through a concave die (4) that is consistent with the outer cross-sectional dimensions of the copper tube, thereby completing the extrusion molding of the arc-shaped crystallizer copper tube; S5. Cleaning and repairing the guide hole: After extrusion molding, the filler (2) in the guide hole is cleaned; after cleaning, the guide hole is repaired to ensure that the size and roundness of the guide hole meet the requirements of the drawing; S6. Sawing and milling processing: trim the total length of the copper tube according to the requirements of the drawing, saw the two ends of the copper tube of the guide hole type curved crystallizer, and process the pallet groove to complete the processing of the copper tube of the guide hole type curved crystallizer.

2. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1 is characterized in that: The inner cavity size of the rectangular blank (3) is 6-8 mm larger than the inner cavity of the finished copper tube to ensure smooth insertion of the subsequent arc core rod; the wall thickness of the rectangular blank (3) is made according to a deformation rate of 18%, that is, the wall thickness of the rectangular blank X = S / (1-18%): wherein: S is the theoretical wall thickness of the finished product; the rectangular blank (3) is in an annealed state.

3. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1 is characterized in that: The processing of the guide hole belongs to the category of fine deep hole processing, which requires ensuring the spacing size of the holes, the processing direction of the holes, the position tolerance between the inner cavity of the copper tube and the holes; when processing the guide hole: the rectangular blank (3) is placed on a high-precision special deep hole drilling and boring machine with a guide device for processing, and the guide hole is drilled by drilling at both ends according to the coordinate position to reduce the position error when drilling the guide hole and improve the processing accuracy.

4. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1 is characterized in that: A tin-bismuth alloy is selected as the filler (2) to reduce the ellipticity error of the guide hole. When filling, all holes at one end of the copper tube with the bottom are plugged and hammered tightly with a conical copper plug (5). The copper tube is preheated to 130°C and placed with the bottom end facing downward. A tin-bismuth alloy block is heated to 160-180°C in a crucible, and molten tin-bismuth alloy liquid is poured into the guide hole to fill it. After the copper tube is cooled to room temperature, it is formed and stretched to minimize the deformation of the guide hole and ensure that the inner cavity of the copper tube fits the surface of the core rod.

5. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1 is characterized in that: During the copper tube extrusion forming process, the arc core rod (1) is connected to the slider of the horizontal hydraulic press through a hole at one end through a pin shaft, and then the straight blank (3) is put on the arc core rod (1), and the other end of the arc core rod (1) is pushed to the bottom of the inner cavity of the straight blank (3); the die (4) is placed against the die base plate on the hollow beam of the horizontal hydraulic press, and the arc core rod (1) moves under the drive of the slider of the horizontal hydraulic press, thereby driving the straight blank (3) into the die (4). Since the straight blank (3) in the annealed state has good plasticity and ductility, the straight blank (3) is formed in the cavity. When passing through the die (4), under the extrusion of the die (4), the inner cavity of the straight square blank (3) gradually closes to the surface of the arc core rod (1) and extends along the arc core rod (1). At the same time, under the action of the extrusion resistance, the position of the die (4) changes with the position of the arc core rod (1), that is, the angle of the die (4) swings along the arc surface of the back and slides up and down along the die base plate. When the straight square blank (3) passes through the die (4) as a whole, the extrusion molding of the copper tube is completed, and then a guide hole type arc crystallizer copper tube with an inner cavity and an outer shape that meet the requirements is extruded.

6. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1, characterized in that: When cleaning and repairing the diversion hole: a steel receiving tray is placed at the bottom of the well-type heat treatment furnace, and the bottom end of the copper tube strip that has been extruded and formed is placed upright on the receiving tray; the copper tube is heated to 150°C, and the tin-bismuth alloy melts and flows into the steel receiving tray for recovery; a ball-end rotary file consistent with the design size of the drawing is used, and an extension rod (8) is used in conjunction with the extension rod (8), the length of the extension rod (8) is 60% of the total length of the copper tube, and the diameter is Φ5 cold-drawn steel bar, which is butt-welded to the ball-end rotary file handle (9); a hand drill or a horizontal milling machine is used as the power, and the ball-end rotary file head (10) is used to expand and repair the diversion hole from both ends, and it is ensured that the sum of the expansion depths at both ends is not less than the total length of the copper tube; because the ball-end rotary file is guided by the hole, the extension rod (8) used is elastic and bends with the hole, thereby achieving expansion of the elliptical diversion hole, ensuring that the size and roundness of the diversion hole meet the requirements of the drawing.

7. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1, characterized in that: Saw the two ends of the copper tube of the guide hole type curved crystallizer, leaving a processing allowance of 5-10mm at each end, trim the total length of the copper tube, process the pallet groove, and then complete the processing of the copper tube of the guide hole type curved crystallizer.

8. The processing technology of the guide hole type curved crystallizer copper tube according to claim 1, characterized in that: The material of the crystallizer copper tube is chromium-zirconium copper or silver-copper; when chromium-zirconium copper is selected, the composition ratio by weight is: Cr: 0.9%, Zr: 0.2%, and the rest is Cu; when silver-copper is selected, the composition ratio by weight is: Cu+Ag≥99.9%, Ag: 0.08-0.12%; P: 0.004-0.012%.

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