A uniform heating and heat preservation device for magnesium bars before the cross-rolling piercing process

Abstract

The present invention provides a uniform heating and heat preservation device for magnesium rods before the oblique rolling and perforation process, wherein the liner is welded with the centering liner, and the left and right ends of the liner are provided with heat-insulating end plates, and the heat-insulating end plates and the centering liner are matched in a sliding manner; the left and right sides of the furnace body are riveted with heat-resistant guide rails, and the liner can roll on the heat-resistant guide rails; it is installed on the inner wall of the furnace body by resistance wires; the front and rear sides of the furnace body are provided with furnace door guide rails, and the furnace door guide rails are placed at the front and rear furnace door outlets near the outer wall of the furnace body, and the furnace door guide rails are used to ensure the up and down sliding of the furnace door; the furnace body is placed on the furnace frame as a whole; and the automatic blocking device is placed on the upper side of the furnace body near the outlet. The present invention greatly improves the uniformity of the temperature of the rod when it is discharged from the furnace as a whole, solves the drawback of eccentricity in the perforation process, and significantly improves the yield rate of the pipe; the setting of the automatic blocking device saves the process of manual unloading, reduces the heat loss when opening and closing the furnace door, and improves the efficiency and safety of production.

Description

Technical Field

[0001] The invention belongs to the field of magnesium alloy bar heating, and in particular relates to a multifunctional heating device which is specially used before the oblique rolling and piercing process of magnesium alloy pipes and integrates the uniform heating function of the magnesium alloy bars and the heat preservation function of the bars after they are taken out of the furnace. Background Art

[0002] As an advanced and efficient production process for magnesium alloy seamless pipes, the oblique rolling and piercing process has extremely strict requirements on the uniformity of the initial rolling temperature and the temperature of the bar billet during the piercing and rolling process of magnesium alloy seamless pipes. At present, the heating furnaces used in the processing process are mostly high-temperature electric furnaces, which use thermocouples for temperature measurement. There are generally problems that are difficult to meet the technical requirements of the oblique rolling and piercing process. The specific contents are as follows:

[0003] Firstly, during the piercing and rolling process, the initial rolling temperature of the magnesium alloy bar is required to be approximately between 400°C and 520°C. During the operation process, the temperature of the resistance wire needs to be about 50°C to 100°C higher than the furnace temperature of the bar, which is close to the ignition point of the magnesium alloy of 600°C to 630°C. However, in the traditional heating method, the distance between the surface of the bar and the resistance wire is not controlled, and the process temperature range is mostly located in the range of low temperature control accuracy of traditional industrial furnaces. During the heating process, the temperature surge phenomenon is obvious and the temperature fluctuates greatly, which can easily lead to combustion of the magnesium bar and cause safety hazards. At the same time, the existing heating method has uneven temperature when the bar is heated.

[0004] Secondly, magnesium alloys dissipate heat very quickly, especially when in contact with metal rigid bodies. During the oblique rolling and piercing process, the allowable process temperature range is extremely narrow; the conventional handling method causes the temperature of the magnesium alloy bars to be lower than the required process temperature range before the piercing machine after the magnesium alloy bars are taken out of the furnace, which causes the bars to get stuck during piercing and rolling; at the same time, as magnesium alloys are thermally stress-sensitive materials, the deformation resistance varies greatly at different temperatures, which can easily cause thermal eccentricity in the magnesium alloy bar piercing and rolling process, seriously restricting the product yield.

[0005] In addition, if the heating furnace is to be completely modified to improve the temperature control accuracy of the heating furnace at medium and low temperatures, the cost of modifying the existing equipment will be expensive and it will be difficult to meet the requirements of large-scale industrial production. Summary of the invention

[0006] In view of the above situation, the purpose of the present invention is to provide a uniform heating and insulation device for magnesium rods before the oblique rolling and piercing process, which can effectively ensure the accurate, safe and efficient temperature control of the heating process before the oblique rolling and piercing process of magnesium alloys, as well as the insulation performance after furnace exit.

[0007] To achieve the above object, the technical solution adopted by the present invention is: to provide a uniform heating and heat preservation device for magnesium rods before the skew rolling piercing process, including: a lining tube, a centering lining plate, a heat insulation end plate, upper and lower heat-resistant guide rails, resistance wires, a furnace body, a furnace door, furnace door guide rails, a furnace frame and an automatic blocking device; wherein, six groups of centering lining plates are evenly distributed in the circumferential direction of the inner wall of the lining tube, and the connection mode between the lining tube and the centering lining plate is welding. After the magnesium rod is placed in the lining tube, it is automatically centered by the centering lining plate; heat insulation end plates are installed at the left and right ends of the lining tube, but the notch on the heat insulation end plate is in sliding fit with the centering lining plate to ensure the centering of the heat insulation end plate, and a certain gap is reserved between the heat insulation end plate and the inner wall of the lining tube. The heat insulation end plate and the centering lining plate are in a sliding fit mode; heat-resistant guide rails are riveted on the left and right sides of the furnace body, and the lining tube can roll on the heat-resistant guide rails; the heating belt composed of resistance wires includes four groups: an upper heating belt, a lower heating belt, a left heating belt and a right heating belt, which are respectively installed on the inner walls of the upper, lower, left and right sides of the furnace body. The distance between the resistance wire and the left and right ends and the outer surface of the lining tube is 50 mm to 80 mm; furnace door guide rails are installed on the front and rear sides of the furnace body, and the furnace door guide rails are placed near the outer wall of the furnace body at the exits of the front and rear furnace doors, and the up and down sliding of the furnace door is ensured through the furnace door guide rails; the whole furnace body is placed on the furnace frame; the automatic blocking device is placed on the upper side of the furnace body near the exit.

[0008] The heat-resistant guide rail is provided with shoulders in the axial direction of the lining tube, which restricts the rotational movement of the lining tube with the radius as the axis, and ensures that the lining tube can only perform translational movement along the length direction of the heat-resistant guide rail.

[0009] The shape of the centering lining plate is an isosceles trapezoid, and the six groups of guide plates evenly distributed in the circumferential direction form a flared hollow cavity at the inlet and outlet of the lining tube.

[0010] The automatic blocking device is installed on the upper surface of the furnace body, and it includes: a left support, a right support, a servo motor, a sliding guide rail platform, a left sliding rack, a right sliding rack, a gear, a gear shaft, a wire rope group, a wire hook and a block; wherein, the servo motor is fixed on the left support located on the upper surface of the furnace body and drives the gear shaft to rotate; the left and right ends of the gear shaft are in shaft hole fit and sleeved on the shaft holes of the left and right supports; a gear is installed on the gear shaft, and the gear shaft and the gear are connected by a key; left and right sliding racks are installed on the front and rear sides of the gear, and the rotation of the gear drives the sliding racks to move up and down. The displacement of the sliding racks in other directions is slidingly constrained by the sliding guide rail platform fixed on the upper surface of the furnace body. A wire hook and a block are respectively installed on the left and right sliding racks; when the rotation of the gear drives the left sliding rack to move upward, the wire hook pulls the furnace door open through the wire rope group. At the same time, the rotation of the gear also drives the right sliding rack to move downward, and the block contacts the outer surface of the lining tube to realize the blocking function of the lining tube, avoiding the slipping of multiple rods at one time and affecting the production rhythm.

[0011] Preferably, the furnace body is arranged obliquely relative to the ground, and the inclination angle is about between 10° and 15°.

[0012] Preferably, electric opening devices are installed on the furnace doors at the outlet and the inlet, which have three working positions: opening and closing at both ends simultaneously, opening on the left and closing on the right, and opening on the right and closing on the left.

[0013] In addition, in the technical solution provided by the present application, the lining tube and the heat insulation end plate are equipped with a hot state recovery - recycling - secondary feeding device, which can realize the recycling of the lining tube and the heat insulation end plate. At the same time, a preheating and heat preservation device for the lining tube and the heat insulation end plate can be added during the recycling process of the lining tube and the heat insulation end plate.

[0014] The beneficial effects of the present invention are as follows: The magnesium rod is sleeved inside the lining tube, and heat insulation end plates are installed at both the left and right ends of the lining tube; during the heating process of the rod, the direct heat radiation of the resistance wire is isolated by the lining tube and the heat insulation end plate. Utilizing the excellent heat conduction performance of the metal itself, a circumferentially uniform heating cavity is quickly formed. After the lining tube and the heat insulation end plate are evenly heated, the heat is indirectly transferred to the magnesium rod, avoiding the generation of local overheating phenomena during the process of directly heating the magnesium rod by the resistance wire, thereby increasing the overall allowable heating temperature of the rod and enabling the magnesium rod to have an outlet temperature of 550°C; during the process of the rod being taken out of the furnace, the steel materials of the bushing and the heat insulation end plate play the role of a heat preservation cover in the air; at the same time, the use of the bushing and the heat insulation end plate avoids the direct contact between the magnesium rod and the piercing mill guide rail (metal rigid body), playing a good heat insulation role; when the whole composed of the bushing, the heat insulation end plate and the magnesium rod is transported to the front of the piercing mill, the feeding push rod on the piercing mill pushes the rear heat insulation end plate to drive the magnesium rod and the front heat insulation end plate to move forward (at this time, the lining tube is blocked by the guiding ring on the piercing mill and stays in place). After the front heat insulation end plate slides out of the lining tube, it falls into the recycling device under the action of gravity, and the magnesium rod and the rear heat insulation end plate continue to move forward to complete the feeding process of the magnesium rod. The whole process is completed without interruption, greatly shortening the feeding time of the magnesium rod and further controlling the heat dissipation. Description of the Drawings

[0015] Figure 1 General assembly drawing of the uniform heating and heat preservation device for magnesium alloy rods;

[0016] Figure 2 Schematic diagram of the inner cavity device of the furnace body;

[0017] Figure 3 Schematic diagram of the arrangement of resistance wires in the furnace body;

[0018] Figure 4 Schematic diagram of the heat insulation device;

[0019] Figure 5 Cross-sectional schematic diagram of the heat insulation device;

[0020] Figure 6 Automatic blocking device componentsFigure 1 ;

[0021] Figure 7 Automatic blocking device components Figure 2 ;

[0022] Figure 8 Schematic diagram of the blocking station of the automatic blocking device;

[0023] In the figure: 1. Furnace body; 2. Furnace door guide rail; 3. Furnace frame; 4. Furnace door; 5. Wire rope group; 6. Lifting lug; 7. Resistance wire; 8. Liner tube; 9. Centering lining plate; 10. Heat insulation end plate; 11. Magnesium rod; 12. Heat-resistant guide rail; 13. Servo motor; 14. Left sliding rack; 15. Right sliding rack; 16. Wire hook; 17. Sliding guide rail platform; 18. Gear; 19. Gear shaft; 20. Stop block. Specific implementation mode

[0024] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Based on the solutions in the present invention, all other solutions obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Next, the present invention will be described in conjunction with the drawings. As Figures 1 to 8 shown, the present invention provides a multifunctional heating device that is specifically used before the skew rolling piercing process of magnesium alloy tubes and integrates the functions of uniform heating of magnesium alloy bars and heat preservation after the bars are taken out of the furnace. It mainly includes a furnace body 1, a furnace door guide rail 2, a furnace frame 3, a furnace door 4, a wire rope group 5, a lifting lug 6, a resistance wire 7, a liner tube 8, a centering lining plate 9, a heat insulation end plate 10, a magnesium rod 11, a heat-resistant guide rail 12, and an automatic blocking device. The automatic blocking device consists of a servo motor 13, a left sliding rack 14, a right sliding rack 15, a wire hook 16, a sliding guide rail platform 17, a gear 18, a gear shaft 19, a stop block 20, a left support 21, and a right support 22.

[0026] As Figure 1 shown, the furnace body 1 is placed on the furnace frame 3. A furnace door guide rail 2 is installed at the entrance and exit of the furnace body 1, and the furnace door guide rail 2 and the furnace body 1 are fixed by screws; the rail groove of the furnace door guide rail 2 is in sliding fit with the furnace door 4. A lifting lug is installed on the furnace door 4 and is connected in series with the automatic blocking device placed on the upper side of the furnace body 1 through the wire rope group 5.

[0027] As Figure 2 , 3As shown, resistance wires 7 are installed around the inner cavity of the furnace body 1, and heat-resistant guide rails 12 are installed on the upper parts of the left and right sides. The lining tube 8 can slide on the heat-resistant guide rails 12. It should be emphasized that the heat-resistant guide rails are provided with shoulders in the axial direction of the lining tube 8 to restrict the rotational movement of the lining tube 8 around the radius axis, ensuring that the lining tube 8 can only perform translational movement along the length direction of the heat-resistant guide rails 12.

[0028] As Figure 4 , 5 As shown, six groups of centering lining plates 9 are evenly distributed in the circumferential direction on the inner wall of the lining tube 8. The connection method between the lining tube 8 and the centering lining plates 9 is welding. After the magnesium rod 11 is placed into the lining tube 8, it is automatically centered by the centering lining plates 8; and heat-insulating end plates 10 are installed at both ends of the magnesium rod 11; the heat-insulating end plates 10 and the centering lining plates 9 are in a sliding fit. It should be emphasized that the shape of the centering lining plates 9 is an isosceles trapezoid, and the six groups of guide plates evenly distributed in the circumferential direction form a flared hollow cavity at the inlet and outlet of the lining tube.

[0029] As Figures 6 to 8 As shown, the automatic blocking device mainly includes a wire rope group 5, a servo motor 13, a left sliding rack 14, a right sliding rack 15, a wire hook 16, a sliding guide rail platform 17, a gear 18, a gear shaft 19, a stop block 20, a right support 22, and a left support 21. The servo motor 13 is fixed on the left support 21 and drives the gear shaft 19 to rotate; the left and right ends of the gear shaft 19 are fitted through shaft holes and sleeved on the shaft holes of the left support 21 and the right support 22; a gear 18 is installed on the gear shaft 19, and the gear shaft 19 and the gear 18 are connected by a key; the left sliding rack 14 and the right sliding rack 15 are installed on both sides of the gear 18 to make the sliding racks move up and down horizontally, and the displacement of the sliding racks in other directions is restricted by the sliding guide rail platform. A wire hook 16 and a stop block 20 are respectively installed on the left sliding rack 14 and the right sliding rack 15; when the gear 18 rotates to drive the left sliding rack 14 to move upward, the wire hook 16 pulls the furnace door open through the wire rope group 5. At the same time, the rotation of the gear 18 also drives the right sliding rack 15 to move downward, completing the blocking function of the lining tube 8 and avoiding the situation of multiple rod materials slipping at one time and affecting the production rhythm.

[0030] Specific working principle of the present invention: The magnesium bar 11 is sent into the liner 8 by the pushing device, and automatic centering is completed through the centering liner plate 9, and heat-insulating end plates 10 are covered at both ends; thereafter, the rear furnace door 4 is opened, and multiple processed magnesium bars 11 are loaded at one time. The liner 8 sleeved outside the magnesium bar slides on the track of the heat-resistant guide rail 12 under the action of gravity and is arranged in a stepped shape from bottom to top in sequence; after the magnesium bars 11 are loaded into the furnace, the rear furnace door 4 is closed; the resistance wires 7 on the four walls of the furnace body 1 start to work, and the heat generated by the resistance wires 7 is radiated to the outside of the liner 8 and the heat-insulating end plates 10, forming a uniform heat-insulating annular heating cavity, and the heat is evenly transferred to the magnesium bars 11. When the temperature reaches the required temperature and is kept warm for a certain period of time, the servo motor 13 is started, the gear 18 is driven to rotate through the gear shaft 19, the left sliding rack 14 moves upward, and the wire hook 16 is driven to move upward, and the front furnace door 4 is pulled open by the wire rope group 5, and the first magnesium bar 11 near the outlet of the furnace body 1 starts to fall; at the same time, the gear 18 drives the right sliding rack 15 to move downward, so that the stopper 20 is inserted into the furnace body 1 to block the downward trend of the second magnesium bar 11 near the furnace outlet under the action of gravity (as Figure 8 shown); after the first magnesium bar 11 finishes falling, the servo motor 13 reverses, the left sliding rack 14 moves downward, and the wire hook 16 is driven to move downward, and the front furnace door 4 closes under the action of gravity; at the same time, the gear 18 drives the right sliding rack 15 to move upward, the stopper 20 retracts, and the second magnesium bar 11 near the furnace outlet falls to the outlet of the furnace body 1 under the action of gravity.

[0031] After the first magnesium bar 11 falls, it slides onto the guide groove of the piercing machine along the guide rail on the piercing machine. The cylinder on the piercing machine is started, and the heat-insulating end plate 10 and the magnesium bar 11 are pushed forward. The liner 8 is caught in place by the guide ring. After being pushed for a certain distance, the heat-insulating end plate 10 on the front side of the pushing direction slides into the recovery tank, and the heat-insulating end plate 10 on the rear side continues to push the magnesium bar 11 forward to complete the first bite process of the magnesium bar during skew rolling piercing.

Claims

1. A uniform heating and heat preservation device for magnesium bars before the skew rolling piercing process, mainly including a lining tube, a centering lining plate, a heat insulation end plate, upper and lower heat-resistant guide rails, resistance wires, a furnace body, a furnace door, furnace door guide rails, a furnace frame and an automatic blocking device; Among them, Six groups of centering lining plates are evenly distributed in the circumferential direction on the inner wall of the lining tube. The connection method between the lining tube and the centering lining plate is welding. After the magnesium bar is placed in the lining tube, it is automatically centered by the centering lining plate; heat insulation end plates are installed at the left and right ends of the lining tube. The notch of the heat insulation end plate is in sliding fit with the centering lining plate to ensure the centering of the heat insulation end plate, and there is a certain gap between the heat insulation end plate and the inner wall of the lining tube. The heat insulation end plate and the centering lining plate adopt a sliding fit method; heat-resistant guide rails are riveted on the left and right sides of the furnace body, and the lining tube can roll on the heat-resistant guide rails; a heating belt is composed of resistance wires, and there are four groups in total: an upper heating belt, a lower heating belt, a left heating belt and a right heating belt, which are respectively installed on the inner walls of the upper, lower, left and right sides of the furnace body; furnace door guide rails are installed on the front and rear sides of the furnace body. The furnace door guide rails are placed near the outer wall of the furnace body at the front and rear furnace door exits, and the up and down sliding of the furnace door is ensured through the furnace door guide rails; the whole furnace body is placed on the furnace frame; the automatic blocking device is placed on the upper side of the furnace body near the exit; The automatic blocking device is installed on the upper surface of the furnace body, and its structure includes: a left support, a right support, a servo motor, a sliding guide rail platform, a left sliding rack, a right sliding rack, a gear, a gear shaft, a wire rope group, a wire hook and a block; among them, the servo motor is fixed on the left support located on the upper surface of the furnace body and drives the gear shaft to rotate; the left and right ends of the gear shaft are in hole-shaft fit and are sleeved on the shaft holes of the left and right supports; a gear is installed on the gear shaft, and the gear shaft and the gear are connected by a key; left and right sliding racks are respectively installed on the front and rear sides of the gear. The rotation of the gear drives the sliding racks to move up and down horizontally, and the displacement of the sliding racks in other directions is slidingly restricted by the sliding guide rail platform fixed on the upper surface of the furnace body; a wire hook and a block are respectively installed on the left and right sliding racks; when the gear rotates to drive the left sliding rack to move upward, the wire hook pulls the furnace door open through the wire rope group. At the same time, the rotation of the gear also drives the right sliding rack to move downward, and the block contacts the outer surface of the lining tube; During the heating and discharging process of the magnesium bar, a centering lining plate, a lining tube and a heat insulation end plate are sleeved outside the magnesium bar; the heat-resistant guide rail is processed with a shoulder in the axial direction of the lining tube, and the length direction of the shoulder is perpendicular to the axial direction of the lining tube.

2. A uniform heating and heat preservation device for magnesium bars before the skew rolling piercing process as described in claim 1, characterized in that, The distance between the resistance wires on the upper and lower walls of the furnace body and the left and right ends and the outer surface of the lining tube is 50 mm to 80 mm.

3. A uniform heating and heat preservation device for magnesium bars before the skew rolling piercing process as described in claim 1, characterized in that, The shape of the centering lining plate is an isosceles trapezoid, and the six groups of guide plates evenly distributed in the circumferential direction form a flared hollow cavity at the inlet and outlet of the lining tube.

4. A uniform heating and heat preservation device for magnesium bars before the skew rolling piercing process as described in claim 1, characterized in that, The furnace body is arranged obliquely relative to the ground, and the inclination angle is about between 10° and 15°.

5. A uniform heating and heat preservation device for magnesium bars before the skew rolling piercing process as described in claim 1, characterized in that, electric opening devices are installed on the furnace doors at both the outlet and the inlet, and there are three working positions: opening and closing at both ends simultaneously, opening on the left and closing on the right, and opening on the right and closing on the left.

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