A hot extrusion device and a hot extrusion process for a dual-phase steel bar

Abstract

The application discloses a kind of hot extrusion device and its hot extrusion process of dual-phase steel bar, it is related to steel bar processing technical field.It includes frame body, horizontal hot extrusion mechanism and cooling mechanism;The frame body includes first support frame and second support frame, the horizontal hot extrusion mechanism includes rotary disc heating seat rotationally arranged between first support frame and second support frame, and the surface of rotary disc heating seat is fixedly embedded with a plurality of die heating jackets.The application uses rotary disc heating seat to realize continuous preheating of blank by matching multiple die heating jackets, which can simultaneously complete constant temperature preheating of dual-phase steel blank in batches, avoiding the problem of excessive temperature difference caused by intermittent heating of single blank;Uniform preheating can reduce the temperature difference inside and outside the blank, effectively inhibit the cracking defects on the surface of the bar during extrusion, and at the same time, the continuous feeding and preheating of the rotary disc can seamlessly connect with the rear-end hot extrusion process, saving the blank transfer and cooling loss, and improving the overall production continuity.

Description

Technical Field

[0001] This invention relates to the field of steel bar processing technology, specifically to a hot extrusion apparatus and hot extrusion process for duplex steel bars. Background Technology

[0002] Duplex steel combines the advantages of both austenitic and ferritic materials, exhibiting excellent strength and corrosion resistance. It is widely used in the fields of chemical engineering and precision piping for semiconductors. Hot extrusion is a common process used in the industry to produce duplex steel bars.

[0003] Patent document CN212652424U discloses a beryllium rod straightening device and a hot extrusion molding machine with the straightening device. This technology usually has the following problems during use: First, the extrusion equipment is not equipped with a slag removal structure, and glass powder and metal oxide waste residue are easily accumulated on the inner wall of the extrusion sleeve, requiring manual cleaning after machine shutdown. The waste residue can also scratch the high-temperature billet, significantly increasing the defect rate of finished products. Second, the traditional cooling method only sprays from the top and one side, and the static cooling of the workpiece is prone to local temperature differences, resulting in severe bending and deformation of the rod and difficulty in ensuring the uniformity of the metallographic structure. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings in the prior art and to provide a hot extrusion device for duplex steel bars with a more reasonable structural design, so as to reduce the metal deformation resistance, stabilize the metallographic structure of duplex steel, and improve the finished product qualification rate.

[0005] Accordingly, the present invention also provides a hot extrusion process for duplex steel bars, enabling seamless cyclic switching between the feeding, preheating, and extrusion stations.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a hot extrusion apparatus for duplex steel bars, comprising a frame body, a horizontal hot extrusion mechanism, and a cooling mechanism; the frame body includes a first support frame and a second support frame; the horizontal hot extrusion mechanism includes a turntable heating seat rotatably disposed between the first support frame and the second support frame; a plurality of mold heating sleeves are fixedly embedded on the surface of the turntable heating seat; two guide rods are disposed on the left side of the first support frame; guide blocks are slidably sleeved on the surface of each of the two guide rods; an extrusion sleeve is fixedly disposed between the two guide blocks; a coaxial extrusion bar is slidably fitted on the inner wall of the extrusion sleeve; and the left side of the first support frame is fixedly... The device is equipped with two first servo hydraulic cylinders. Two push rods are symmetrically fixed at the end of the extrusion sleeve away from the turntable heating seat. A second servo hydraulic cylinder is installed at one end of each push rod. The horizontal hot extrusion mechanism is used to complete the constant temperature preheating and graded extrusion forming of the duplex steel billet. A multi-station synchronous preheating mechanism is set inside the turntable heating seat. The multi-station synchronous preheating mechanism includes multiple sets of mold heating sleeves evenly arranged along the circumference of the turntable heating seat. The multiple sets of mold heating sleeves synchronously control the constant temperature to realize the batch synchronous preheating of the billet. The mold heating sleeves complete the cycle switching of feeding, preheating, and extrusion stations as the turntable heating seat rotates. This eliminates the cooling loss during billet transfer and reduces the temperature difference between the inside and outside of the billet.

[0007] A graded extrusion drive mechanism is provided between the extrusion sleeve and the extrusion bar. The graded extrusion drive mechanism is composed of a first servo hydraulic cylinder, a push rod, and a second servo hydraulic cylinder. The first servo hydraulic cylinder drives the extrusion sleeve to move forward as a whole to cover the blank inside the heating sleeve of the limiting mold. The second servo hydraulic cylinder independently drives the extrusion bar to apply extrusion force forward. The two-stage step-by-step action smoothly outputs extrusion force, reduces the deformation resistance of high-temperature metal, and ensures the dimensional accuracy of small-diameter bar forming.

[0008] After the biphase steel billet inside the mold heating jacket has completed constant temperature preheating, the first servo hydraulic cylinder pushes the extrusion sleeve to coaxially extend into the mold heating jacket to complete the sealing and positioning of the billet. The second servo hydraulic cylinder drives the extrusion bar to extrude the billet forward. The billet is extruded and formed through the discharge hole of the mold heating jacket. After the extrusion is completed, the first servo hydraulic cylinder pulls the extrusion sleeve back to reset. The jet assembly is simultaneously linked to blow away the waste residue on the inner wall of the sleeve. The extruded high-temperature steel bar is automatically sent to the cooling mechanism to complete the rotation and uniform water cooling and shaping.

[0009] Preferably, a jet assembly is provided on the left side of the first support frame. The jet assembly is used to remove the waste residue remaining on the surface of the extrusion sleeve. The jet assembly includes an annular jet pipe fixed inside the first support frame. Several jet nozzles are fixedly embedded inside the annular jet pipe. The jet assembly also includes two air cylinders. The telescopic ends of the two air cylinders are fixedly connected to U-shaped linkage plates. The jet assembly completes the purging operation synchronously with the extrusion sleeve as it moves forward and backward, without the need for additional power drive.

[0010] The jet assembly also includes a T-shaped air pipe, a guide pipe, a one-way air inlet valve, and an air inlet pipe. The upper end of the U-shaped linkage plate is rigidly connected to the guide block. The output end of the air cylinder is connected to the T-shaped air pipe. The two branches of the T-shaped air pipe are respectively connected to the guide pipe. The end of the guide pipe is connected to the annular jet pipe. The air cylinder inlet end is equipped with an air inlet pipe with a one-way air inlet valve. The one-way air inlet valve only allows external air to enter the air cylinder in one direction and blocks the high-pressure airflow from flowing back and depressurizing. The annular jet pipe is arranged coaxially around the extrusion sleeve. Multiple sets of jet nozzles are arranged radially inward along the ring body and can be simultaneously aligned with the outer wall, port, and inner channel of the extrusion sleeve.

[0011] Preferably, the output end of the air cylinder is fixedly connected to a T-shaped air pipe, the output end of the T-shaped air pipe is fixedly connected to an air guide pipe, the air inlet end of the air cylinder is fixedly provided with an air inlet pipe, and the end of the air inlet pipe is provided with a one-way air inlet valve; the one-way air inlet valve is used to prevent the high-pressure airflow from flowing back and depressurizing, thus ensuring the cleaning effect of the air jet.

[0012] When the guide block retracts and resets with the extrusion sleeve, it simultaneously pulls down the U-shaped linkage plate. The U-shaped linkage plate presses down to compress the internal volume of the air cylinder, and the air inside the air cylinder is compressed to form a high-pressure purging airflow. At this time, the one-way air inlet valve is automatically closed and locked by the internal air pressure. The high-pressure airflow is completely diverted through the T-shaped air pipe and sent to the two side air guide pipes, and then merges into the annular jet pipe and is sprayed from multiple sets of jet nozzles at multiple angles to thoroughly flush the metal oxide slag and glass lubricating powder attached to the inner and outer walls of the extrusion sleeve. When the extrusion sleeve moves forward with the first servo hydraulic cylinder and extends into the mold heating sleeve, the U-shaped linkage plate simultaneously lifts up to release the air cylinder, forming a negative pressure inside the air cylinder. The one-way air inlet valve automatically opens, and external air is replenished into the air cylinder through the air inlet pipe to complete the reserve of purging air source for the next cycle.

[0013] Preferably, the telescopic end of the second servo hydraulic cylinder is fixedly connected to an advanced push plate. The surface of the advanced push plate is provided with a sliding through hole that matches the push rod. The advanced push plate is slidably connected to the surface of the push rod through the sliding through hole. The sliding through hole provides sliding guidance for the advanced push plate, ensuring that the extrusion force is output coaxially and stably.

[0014] The push rod passes through the sliding through hole to form a coaxial limiting guide pair. The clearance fit between the inner wall of the sliding through hole and the outer wall of the push rod constrains the advanced push plate to slide linearly along the axial direction of the push rod. The center of the advanced push plate is rigidly fixed to the tail of the extrusion bar. The first servo hydraulic cylinder first pushes the push rod and the extrusion sleeve forward to cover the billet inside the mold heating sleeve, completing the outer perimeter limiting and sealing of the billet. Then, the second servo hydraulic cylinder outputs thrust to drive the advanced push plate to slide forward along the push rod. The advanced push plate pushes the extrusion bar to apply extrusion force to the constant temperature billet. The sliding through hole restricts the radial displacement of the advanced push plate throughout the process. The extrusion force is evenly transmitted to the billet along the central axis, avoiding uneven wall thickness and surface wear defects caused by eccentric extrusion.

[0015] Preferably, a drive motor is fixedly mounted on the surface of the second support frame, and a drive gear is fixedly mounted on the output end of the drive motor. Support shafts are coaxially fixed on both the left and right sides of the turntable heating seat, and driven gears are fixedly mounted on the surface of the support shafts. The gear meshing structure enables the turntable heating seat to accurately index and rotate, and switch between heating and extrusion positions.

[0016] The drive gear and driven gear form a precision gear indexing transmission pair. The two support shafts are mounted on the first support frame and the second support frame through bearings, forming a horizontal coaxial support for the turntable heating seat. After the extrusion of a single bar is completed, the extrusion sleeve is fully retracted, and the air jet assembly completes the slag removal process, the drive motor starts and drives the drive gear to mesh with the driven gear to rotate the support shaft synchronously. This drives the turntable heating seat to rotate at a fixed angle, precisely switching the mold heating sleeve, which has completed constant temperature preheating, to the extrusion station coaxial with the extrusion sleeve. At the same time, the empty mold heating sleeve is rotated to the outer loading station, and the operator can simultaneously load new billets, realizing uninterrupted cyclic switching of loading, preheating, and extrusion stations, eliminating billet transfer and cooling losses.

[0017] Preferably, the left end of the mold heating sleeve is the feed port, and the right end of the mold heating sleeve is provided with a discharge hole. The extrusion sleeve can slide into the interior of the mold heating sleeve. The discharge hole limits the outer diameter of the bar forming and is suitable for extrusion of small-diameter precision duplex steel bars.

[0018] The feed inlet, discharge hole, extrusion sleeve, and extrusion bar are arranged coaxially. The discharge hole diameter is smaller than that of the feed inlet, forming a reduced-diameter forming mold cavity. After the turntable heating seat drives the mold heating sleeve to the extrusion station, the billet is placed inside the feed inlet for constant temperature preheating. The first servo hydraulic cylinder pushes the extrusion sleeve to fully extend into the mold heating sleeve to seal the feed inlet, isolating the billet from heat exchange with the outside air and maintaining the overall uniform temperature of the billet. The second servo hydraulic cylinder drives the extrusion bar to push the billet forward. The high-temperature ductile metal flows along the inner cavity of the mold heating sleeve to the discharge hole. The inner wall of the discharge hole restricts the outer diameter of the metal flow, and small-diameter duplex steel bars with uniform outer diameter and smooth surface are extruded in one go. The formed steel bars are directly and continuously transported from the discharge hole to the rear cooling mechanism.

[0019] Preferably, the cooling mechanism includes two crossbeams, and two electric telescopic rods are fixedly installed on the opposite sides of the two crossbeams. A U-shaped frame is fixed to the telescopic end of the two electric telescopic rods. A rotating support cylinder is rotatably installed on the inner side of the U-shaped frame. A number of strip-shaped water permeable holes are opened on the surface of the rotating support cylinder. The strip-shaped water permeable holes allow the cooling water to contact the rod material in all directions, thereby improving the cooling uniformity.

[0020] The two side crossbars, electric telescopic rods, and C-shaped frames form an opening and closing clamping mechanism. After the two sets of C-shaped frames are aligned, they form a complete cylindrical receiving cavity. The rotating support cylinder is rotatably assembled on the inner cylinder seat of the C-shaped frame. Multiple through-type strip-shaped water-permeable holes are evenly opened along the axial direction of the cylinder body. Before the high-temperature steel bar is sent out from the discharge hole, the electric telescopic rods on both sides extend synchronously to push the C-shaped frames to close in opposite directions, clamping the rotating support cylinder to form a closed cooling channel. The cooling water sprayed from above falls vertically through the strip-shaped water-permeable holes and directly wets the entire circumferential surface of the steel bar inside the cylinder, without any cooling dead corners, greatly reducing the radial cooling temperature difference of the steel bar and ensuring a uniform cooling rate.

[0021] Preferably, the output shaft of the rotary motor is rigidly connected to the rotary support cylinder to form a workpiece rotation drive pair, and the rotary support cylinder clamps the steel bar and rotates synchronously. When the cooling water is continuously sprayed downward, the rotary motor drives the rotary support cylinder to rotate at a uniform low speed, causing the internal high-temperature steel bar to rotate 360° circumferentially. The various sides of the steel bar are alternately contacted by the sprayed cooling water, eliminating the local temperature difference caused by continuous rapid cooling on one side, avoiding bending and warping defects caused by unidirectional shrinkage of the steel bar, and improving the mechanical and corrosion resistance properties of the finished product.

[0022] Preferably, the cooling mechanism further includes a horizontal hanger and a conveyor platform fixed to the right side of the second support frame. Several arc-shaped nozzles are fixedly installed on the lower surface of the horizontal hanger, and several conveyor rollers are rotatably arranged on the surface of the conveyor platform. The conveyor rollers receive the cooled bar material to realize automated material discharge and transfer. The horizontal boom suspends multiple sets of arc-shaped nozzles to form a full-area spray water supply mechanism. The arc-shaped nozzles are arranged at an angle downward to form a continuous water curtain that provides continuous circulation cooling water. The conveyor table and multiple parallel conveyor rollers constitute an automatic finished product conveying mechanism. The conveyor rollers can roll freely to reduce the frictional resistance of the steel bar transfer. After the steel bar is water-cooled to the process-specified temperature, the electric telescopic rods on both sides retract synchronously to pull the C-shaped frame apart. The rotating support cylinder separates with the C-shaped frame and releases the steel bar. The cooled and formed duplex steel bar falls onto the surface of the conveyor rollers by its own weight and is continuously transported and collected by the rolling of the conveyor rollers. The entire process does not require manual clamping of high-temperature workpieces, improving production safety and automation.

[0023] This invention also relates to a hot extrusion process for duplex steel bars, which includes the following steps: S1. Before starting the equipment, the operator puts the duplex steel billet into the mold heating sleeve of the turntable heating seat through the feed port; the drive motor drives the turntable heating seat to rotate in sections, and rotates the mold heating sleeve carrying the billet to the coaxial position with the extrusion sleeve; S2. Preheating is completed. The first servo hydraulic cylinder pushes the extrusion sleeve to cover the billet, and the second servo hydraulic cylinder drives the extrusion bar to apply pressure. The billet is extruded from the discharge hole and formed. S3. The extrusion sleeve retracts and resets, simultaneously pulling the U-shaped linkage plate to compress the air cylinder, and the high-pressure airflow blows away the sleeve waste residue through the air nozzle via the pipe route; S4. The high-temperature bar is fed into the rotating support cylinder and cooled by rotating spray water; after cooling, the electric telescopic rod separates the C-shaped frame, and the workpiece falls onto the conveyor roller for delivery.

[0024] Compared with the prior art, the beneficial effects of the present invention are: This device uses a rotary heating seat with multiple sets of mold heating sleeves to achieve continuous preheating of billets. It can simultaneously preheat duplex steel billets in batches at a constant temperature, avoiding the problem of excessive temperature difference caused by intermittent heating of single billets. Uniform preheating can reduce the temperature difference between the inside and outside of the billet, effectively suppressing cracking defects on the surface of the bar during extrusion. At the same time, the continuous feeding and preheating of the rotary table can be seamlessly connected with the subsequent hot extrusion process, eliminating the loss of billet transfer and cooling, and improving the overall production continuity. Relying on the first servo hydraulic cylinder to push the extrusion sleeve and the second servo hydraulic cylinder to drive the extrusion bar for staged extrusion, the extrusion pressure output is stable and controllable, and it can stably achieve one-piece forming of small-diameter duplex steel bars. The extrusion sleeve and the mold heating sleeve are precisely coaxially matched, and the billet is kept at a high temperature throughout the extrusion process, reducing the metal deformation resistance, reducing the problems of pitting and uneven wall thickness on the extruded surface, improving the dimensional accuracy and surface finish of the bar. The dual-servo staged extrusion structure has high forming accuracy and is suitable for small-diameter precision duplex steel bars.

[0025] By setting up an air jet assembly, the air cylinder, U-shaped linkage plate and guide block are linked together to complete the air jet cleaning during the process of the extrusion sleeve exiting the mold heating sleeve. The annular air jet pipe surrounds the extrusion sleeve, and the multi-directional air jet nozzles can remove residual glass powder and metal oxide waste residue from the inner wall and port of the sleeve in all directions. This not only avoids the waste residue remaining in the cylinder from scratching the subsequent duplex steel billet, but also eliminates the need for a separate slag cleaning process, thereby improving the finished product qualification rate and equipment operating efficiency.

[0026] By setting up a rotary spray cooling mechanism, the material is cooled evenly and quickly after discharge, stabilizing the metallographic structure of duplex steel. After extrusion, the bar enters the surface of the rotary support cylinder with water-permeable holes. The rotary motor drives the workpiece to rotate at a uniform speed, and multiple sets of arc-shaped nozzles spray cooling water all around, so that the water-cooled heat exchange of the workpiece is uniform and can achieve rapid cooling. At the same time, the rotary cooling eliminates the bending deformation of the bar caused by uneven local cooling. After cooling, the electric telescopic rod drives the two rotary support cylinders to separate, and the workpiece falls onto the conveyor roller for orderly transfer. The cooling effect is stable and the discharge is neat. Attached Figure Description

[0027] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a schematic diagram of the left-side first-view structure of the present invention; Figure 3 This is a schematic diagram of the rear view structure of the present invention; Figure 4 for Figure 3 Enlarged structural diagram at point A; Figure 5 This is a schematic diagram of the front section structure of the present invention; Figure 6 for Figure 5 Enlarged structural diagram at point B; Figure 7 for Figure 5 Enlarged structural diagram at point C; Figure 8 This is a schematic diagram of the left-side second-view structure of the present invention.

[0028] In the diagram: 1. Frame body; 2. Horizontal hot extrusion mechanism; 3. Cooling mechanism; 4. Jet assembly; 101. First support frame; 102. Second support frame; 201. Turntable heating seat; 202. Die heating sleeve; 203. Guide rod; 204. Guide block; 205. Extrusion sleeve; 206. Extrusion bar; 207. First servo hydraulic cylinder; 208. Push rod; 209. Second servo hydraulic cylinder; 210. Advancing push plate; 211. Sliding through hole; 212. Drive motor; 213. Drive gear; 214. 215. Support shaft; 216. Driven gear; 217. Feed inlet; 218. Discharge hole; 301. Horizontal frame; 302. Electric telescopic rod; 303. C-shaped frame; 304. Rotating support cylinder; 305. Strip-shaped water permeable hole; 306. Rotary motor; 307. Horizontal hanging rod; 308. Conveyor table; 309. Arc-shaped nozzle; 310. Water inlet pipe; 311. Conveyor roller; 401. Annular air jet pipe; 402. Air jet nozzle; 403. Air cylinder; 404. U-shaped linkage plate; 405. Air guide pipe; 406. T-shaped air pipe. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described in conjunction with the embodiments and accompanying drawings.

[0030] See Figures 1-8 The hot extrusion apparatus for duplex steel bars provided by the present invention includes a frame body 1, a horizontal hot extrusion mechanism 2, a cooling mechanism 3, and an air jet assembly 4.

[0031] The frame body 1 includes a first support frame 101 and a second support frame 102. The first support frame 101 is located on the left side of the equipment, and the second support frame 102 is arranged on the right side of the first support frame 101, maintaining a fixed distance from the first support frame 101. The two together support the support shaft 214 of the turntable heating seat 201. An installation platform extends from the right side of the second support frame 102 for assembling all components of the cooling mechanism 3.

[0032] The horizontal hot extrusion mechanism 2 includes a turntable heating seat 201. The turntable heating seat 201 is horizontally mounted between a first support frame 101 and a second support frame 102. Two support shafts 214 are coaxially fixed at both ends of the turntable heating seat 201. The two support shafts 214 are rotatably mounted on the side walls of the first support frame 101 and the second support frame 102 respectively via bearings, allowing the turntable heating seat 201 to rotate horizontally around the support shafts 214. A drive motor 212 is fixedly mounted on the outer wall of the second support frame 102. The output end of the drive motor 212 is rigidly connected to a drive gear 213. A driven gear 215 is fixed to the surface of the support shaft 214 on the same side. The drive gear 213 and the driven gear 215 mesh and transmit power. After the drive motor 212 is powered on, it drives the turntable heating seat 201 to rotate at a uniform speed through the gear pair, realizing multi-station cyclic switching.

[0033] The rotary heating base 201 has multiple sets of mold heating sleeves 202 evenly embedded on its surface. The left end of each mold heating sleeve 202 has a feed inlet 216 for feeding duplex steel billets, and the right end has a discharge hole 217. The feed inlet 216 and discharge hole 217 are coaxially arranged, with the discharge hole 217 having a smaller diameter than the feed inlet 216, suitable for extrusion molding discharge specifications. The rotary heating base 201, equipped with multiple sets of mold heating sleeves 202, provides synchronous constant-temperature preheating, enabling batch preheating of duplex steel billets. Unlike traditional single-heating-tube intermittent heating, this method keeps the billet heating temperature difference within a very small range. The narrow hot working window of duplex steel ensures uniform internal and external temperatures, preventing stress concentration and cracking during extrusion. Simultaneously, the rotary indexing rotation allows for seamless switching between feeding, heating, and extrusion positions, continuously improving the efficiency of continuous production line operation.

[0034] Two guide rods 203 are fixed parallel to each other on the left side of the first support frame 101. The two guide rods 203 are arranged horizontally in the same direction. A guide block 204 is slidably sleeved on the outside of each guide rod 203. An extrusion sleeve 205 is rigidly fixed in the middle of the two guide blocks 204. The extrusion sleeve 205 is coaxial with the mold heating sleeve 202. The outer diameter of the extrusion sleeve 205 matches the inner diameter of the mold heating sleeve 202. The extrusion sleeve 205 can slide horizontally along the guide rods 203 and fully extend into the mold heating sleeve 202 to complete the extrusion operation.

[0035] Two first servo hydraulic cylinders 207 are symmetrically fixed on the left side of the first support frame 101. The telescopic ends of the two first servo hydraulic cylinders 207 are respectively fixedly connected to the side walls of two guide blocks 204. The first servo hydraulic cylinders 207 telescopically extend and retract, driving the guide blocks 204 and the extrusion sleeve 205 to move horizontally back and forth along the guide rod 203, so that the extrusion sleeve 205 extends into and exits the mold heating sleeve 202. The extrusion rod 206 is coaxially slidably assembled inside the extrusion sleeve 205. Two push rods 208 are symmetrically fixed at the end of the extrusion sleeve 205 away from the turntable heating seat 201. The ends of the two push rods 208 are jointly fixed to a limiting circular plate. The center of the limiting circular plate is vertically fixed to a second servo hydraulic cylinder 209.

[0036] The extension end of the second servo hydraulic cylinder 209 is connected to the advanced push plate 210. The center of the advanced push plate 210 is rigidly fixed to the tail of the extrusion rod 206. Two sliding through holes 211 are opened on the surface of the advanced push plate 210. The inner diameter of the sliding through holes 211 is adapted to the outer diameter of the push rod 208. The advanced push plate 210 is sleeved on the surface of the push rod 208 through the sliding through holes 211 and can slide independently along the axial direction of the push rod 208.

[0037] The first servo hydraulic cylinder 207 pushes the extrusion sleeve 205 into the mold heating sleeve 202 to complete the positioning and covering of the billet. The second servo hydraulic cylinder 209 independently drives the extrusion bar 206 to push the billet forward to complete the extrusion molding. The two servo mechanisms are independently controlled and output extrusion pressure in stages. The dual-servo staged extrusion structure can precisely control the two-stage extrusion action, and the extrusion pressure output is stable and impact-free, which is suitable for the forming of small-diameter precision duplex steel bars. The extrusion sleeve 205 and the mold heating sleeve 202 are coaxially matched throughout the process, and the billet is always in the constant temperature environment of the mold heating sleeve 202 to complete the extrusion, which greatly improves the dimensional accuracy and surface finish of the bar.

[0038] The jet assembly 4 is used to automatically remove residual metal oxide slag and glass powder lubricating waste from the inner wall of the extrusion sleeve 205 after it exits the operation. It includes an annular jet pipe 401, which is fixedly installed on the inner frame of the first support frame 101. The annular jet pipe 401 is coaxially arranged with the extrusion sleeve 205. Multiple sets of jet nozzles 402 are evenly embedded in the inner ring wall of the annular jet pipe 401. The jet nozzles 402 face the center of the ring and can be aligned with the outer and inner walls of the extrusion sleeve 205 that pass through the ring. Two air cylinders 403 are symmetrically installed below the first support frame 101. The telescopic ends of the two air cylinders 403 are connected upward to the U-shaped linkage plate 404. The top of the U-shaped linkage plate 404 is rigidly welded to the lower surface of the guide block 204. The guide block 204, the extrusion sleeve 205, the U-shaped linkage plate 404, and the air cylinders 403 form a synchronous linkage structure.

[0039] The air outlet of the air cylinder 403 is connected to the T-shaped air pipe 406. The two branches of the T-shaped air pipe 406 are respectively connected to the air guide pipe 405. The other end of the air guide pipe 405 is connected to the air inlet of the annular jet pipe 401. The air inlet of the air cylinder 403 is connected to an external air inlet pipe, and a one-way air inlet valve is installed at the end of the air inlet pipe.

[0040] During implementation, when the first servo hydraulic cylinder 207 pulls the guide block 204 and the extrusion sleeve 205 backwards from the mold heating sleeve 202, the guide block 204 simultaneously drives the U-shaped linkage plate 404 to pull down the piston rod of the air cylinder 403. The high-pressure gas inside the air cylinder 403 is compressed and transported sequentially through the T-shaped air pipe 406 and the air guide pipe 405 to the annular jet pipe 401. High-pressure airflow is ejected from the surrounding jet nozzles 402 to blow away residual waste residue inside and outside the extrusion sleeve 205. The jet assembly 4 and the extrusion sleeve 205 retract and clean the slag simultaneously. The annular multi-directional jet nozzles 402 provide full coverage and can thoroughly remove residual oxide scale and glass powder residue from the surface of the extrusion sleeve 205, preventing waste residue from scratching the subsequent high-temperature duplex steel billet, reducing the surface defect rate of the finished product, and simultaneously increasing the continuous operation time of the equipment and reducing the frequency of manual shutdown for cleaning.

[0041] The cooling mechanism 3 is arranged in the discharge area on the right side of the second support frame 102. It receives the high-temperature duplex steel bar extruded from the discharge hole 217 of the mold heating sleeve 202, achieving rapid and uniform water cooling after discharge. It includes two sets of horizontal frames 301 and a conveyor table 308. The two sets of horizontal frames 301 are symmetrically fixed to the platform on the right side of the second support frame 102. Two electric telescopic rods 302 are horizontally installed on the inner sides of the two sets of horizontal frames 301 respectively. The telescopic ends of the two electric telescopic rods 302 on the same side are jointly fixed to a set of C-shaped frames 303. The two sets of horizontal frames 301 are arranged in a set. The C-shaped frames 303 are symmetrically aligned, with the rotating support cylinder 304 sandwiched in the middle. The two ends of the rotating support cylinder 304 are rotatably mounted on the inner cylinder seats of the left and right C-shaped frames 303 via bearings. The rotating support cylinder 304 has multiple strip-shaped water permeable holes 305, through which cooling water can pass directly and spray onto the surface of the bar inside the cylinder. A rotary motor 306 is fixed to the outside of the right C-shaped frame 303. The output shaft of the rotary motor 306 is rigidly connected to the right end of the rotating support cylinder 304, which can drive the rotating support cylinder 304 to rotate at a uniform speed.

[0042] A horizontal hanger 307 is erected above the right side of the second support frame 102. Multiple sets of arc-shaped nozzles 309 are fixed at the bottom of the horizontal hanger 307. All arc-shaped nozzles 309 are connected to the water inlet pipe 310 and connected to the circulating cooling water. The arc-shaped nozzles 309 are located directly above the rotating support cylinder 304. The spray water flows vertically downwards and covers the entire area of ​​the rotating support cylinder 304. A conveyor platform 308 is set directly below the rotating support cylinder 304. Multiple parallel conveyor rollers 311 are rotatably installed on the surface of the conveyor platform 308 to receive the cooled bars and convey them outwards.

[0043] When the cooling mechanism 3 is working, the bar is extruded from the discharge hole 217 and directly enters the rotating support cylinder 304 with the left and right sides facing each other. The rotating motor 306 drives the support cylinder to rotate at a constant speed, and the arc-shaped nozzle 309 above continuously sprays cooling water. The water flows through the strip-shaped water-permeable holes 305 and surrounds the bar. After cooling is completed, the electric telescopic rods 302 on both sides retract, the left and right C-shaped frames 303 separate, the rotating support cylinder 304 separates, and the cooled bar falls to the conveying roller 311 for outward transfer. The rotating spray cooling achieves 360° uniform water cooling of the bar, quickly passing through the brittle phase precipitation temperature range of duplex steel, stabilizing the austenite and ferrite two-phase metallographic ratio, and ensuring the corrosion resistance and mechanical properties of the finished product. The workpiece rotation cooling eliminates bending deformation caused by excessively rapid cooling on one side. After cooling, the workpiece is automatically dropped and conveyed, and the output is neat. There is no need for manual transfer of high-temperature workpieces, which improves production safety and product qualification rate.

[0044] In addition, the present invention also provides a hot extrusion process for duplex steel bars, comprising the following steps: S1. Before starting the equipment, the operator puts the duplex steel billet, which has been heated at high temperature, into the empty mold heating sleeve 202 of the turntable heating seat 201 through the feed port 216; the drive motor 212 drives the turntable heating seat 201 to rotate by the gear pair, and the mold heating sleeve 202 containing the billet rotates to the processing station coaxial with the extrusion sleeve 205. S2. After the billet is preheated, the two first servo hydraulic cylinders 207 extend synchronously, pushing the guide block 204 to slide forward along the guide rod 203. The guide block 204 drives the extrusion sleeve 205 to extend into the mold heating sleeve 202. Then the second servo hydraulic cylinder 209 starts, driving the advanced push plate 210 to move forward along the push rod 208. The advanced push plate 210 drives the extrusion rod 206 to apply a stable graded extrusion force to the billet. The high-temperature billet is extruded through the discharge hole 217 at the right end of the mold heating sleeve 202 to form a small-diameter precision duplex steel bar. S3. After the single bar is extruded, the first servo hydraulic cylinder 207 pulls the guide block 204 and the extrusion sleeve 205 to reset and exit the mold heating sleeve 202. When the guide block 204 retracts, it simultaneously pulls down the U-shaped linkage plate 404, compressing the air inside the two air cylinders 403 to form a high-pressure airflow. The airflow is then transported to the annular jet pipe 401 through the T-shaped air pipe 406 and the air guide pipe 405. The jet nozzles 402 arranged around the annular nozzles blow away residual oxide slag and glass powder lubricating waste from the inner wall and port of the extrusion sleeve 205 in all directions. S4. The high-temperature bar extruded through the discharge hole 217 directly enters the rotating support cylinder 304 clamped by the two side chamfered frames 303; the rotary motor 306 drives the rotating support cylinder 304 to rotate at a constant speed, and the arc-shaped nozzle 309 below the horizontal hanger 307 continuously sprays circulating cooling water. The water flows through the strip-shaped water-permeable hole 305 to wrap around the entire bar, and cools it evenly and rapidly. After the cooling reaches the standard, the electric telescopic rod 302 on the cross frame 301 retracts synchronously, the two side chamfered frames 303 separate, and the workpiece falls onto the conveying roller 311 of the conveying table 308 for outward conveying.

Claims

1. A hot extrusion apparatus for duplex steel bars, comprising a frame body (1) composed of a first support frame (101) and a second support frame (102), characterized in that, It also includes a cooling mechanism (3) and a horizontal hot extrusion mechanism (2) for completing the constant temperature preheating and graded extrusion molding of the duplex billet. The horizontal hot extrusion mechanism (2) includes a turntable heating seat (201) rotatably disposed between a first support frame (101) and a second support frame (102). A plurality of mold heating sleeves (202) are embedded on the surface of the turntable heating seat (201). Two guide rods (203) are disposed on the left side of the first support frame (101). Guide blocks (204) are fitted onto each of the two guide rods (203). An extrusion sleeve (205) is fixed between the two guide blocks (204). A coaxial extrusion rod (206) is slidably fitted onto the inner wall of the extrusion sleeve (205). The first support frame (101)... Two first servo hydraulic cylinders (207) are fixed on the left side. Two push rods (208) are symmetrically fixed at the end of the extrusion sleeve (205) away from the turntable heating seat (201). A second servo hydraulic cylinder (209) is provided at one end of the two push rods (208). A multi-station synchronous preheating mechanism is provided inside the turntable heating seat (201). The multi-station synchronous preheating mechanism includes multiple sets of mold heating sleeves (202) evenly arranged around the circumference of the turntable heating seat (201). The mold heating sleeves (202) rotate with the turntable heating seat (201) to complete the cycle switching of feeding, preheating, and extrusion stations. A graded extrusion drive mechanism is provided between the extrusion sleeve (205) and the extrusion bar (206). The graded extrusion drive mechanism is composed of a first servo hydraulic cylinder (207), a push rod (208), and a second servo hydraulic cylinder (209). The first servo hydraulic cylinder (207) drives the extrusion sleeve (205) to move forward as a whole to cover the blank inside the limiting mold heating sleeve (202). The second servo hydraulic cylinder (209) independently drives the extrusion bar (206) to apply extrusion force forward. After the biphase steel billet in the mold heating sleeve (202) is preheated at a constant temperature, the first servo hydraulic cylinder (207) pushes the extrusion sleeve (205) to coaxially extend into the mold heating sleeve (202) to complete the sealing and positioning of the billet. The second servo hydraulic cylinder (209) drives the extrusion rod (206) to extrude the billet forward. The billet is extruded and formed through the discharge hole (217) of the mold heating sleeve (202). After the extrusion is completed, the first servo hydraulic cylinder (207) pulls the extrusion sleeve (205) back to reset. The synchronous linkage jet assembly (4) blows the waste residue on the inner wall of the sleeve. The extruded high-temperature steel rod is automatically sent to the cooling mechanism (3) to complete the rotation and uniform water cooling and shaping.

2. The hot extrusion apparatus for duplex steel bars according to claim 1, characterized in that: A jet assembly (4) is provided on the left side of the first support frame (101). The jet assembly (4) is used to remove the waste residue remaining on the surface of the extrusion sleeve (205). The jet assembly (4) includes an annular jet pipe (401) fixed inside the first support frame (101). Several jet nozzles (402) are fixedly embedded inside the annular jet pipe (401). The jet assembly (4) also includes two air cylinders (403). The telescopic ends of the two air cylinders (403) are fixedly connected to a U-shaped linkage plate (404). The jet assembly (4) completes the purging operation synchronously with the extrusion sleeve (205) moving forward and backward. The jet assembly (4) also includes a T-shaped air pipe (406), an air guide pipe (405), a one-way air intake valve and an air intake pipe. The upper end of the U-shaped linkage plate (404) is rigidly connected to the guide block (204). The output end of the air cylinder (403) is connected to the T-shaped air pipe (406). The two branches of the T-shaped air pipe (406) are respectively connected to the air guide pipe (405). The end of the air guide pipe (405) is connected to the annular jet pipe (401). The air intake end of the air cylinder (403) is equipped with an air intake pipe with a one-way air intake valve. The one-way air intake valve only allows external air to be filled into the air cylinder (403) in one direction and blocks the high-pressure airflow from flowing back and depressurizing. The annular jet pipe (401) is arranged coaxially around the extrusion sleeve (205). Multiple sets of jet nozzles (402) are arranged inwardly along the radial direction of the ring body, and are aligned with the outer wall, port and inner channel of the extrusion sleeve (205).

3. The hot extrusion apparatus for duplex steel bars according to claim 2, characterized in that: The output end of the air cylinder (403) is fixedly connected to a T-shaped air pipe (406), the output end of the T-shaped air pipe (406) is fixedly connected to an air guide pipe (405), and the air inlet end of the air cylinder (403) is fixedly provided with an air inlet pipe. When the guide block (204) retracts and resets with the extrusion sleeve (205), it simultaneously pulls down the U-shaped linkage plate (404). The U-shaped linkage plate (404) presses down the internal volume of the compressed air cylinder (403). The air inside the air cylinder (403) is compressed to form a high-pressure purging airflow. The high-pressure airflow is completely diverted through the T-shaped air pipe (406) and sent to the two side air guide pipes (405). Then it merges into the annular jet pipe (401) and is sprayed from multiple angles by multiple sets of jet nozzles (402) to flush the metal oxide slag and glass lubricating powder attached to the inner and outer walls of the extrusion sleeve (205) in all directions. When the extrusion sleeve (205) moves forward with the first servo hydraulic cylinder (207) and extends into the mold heating sleeve (202), the U-shaped linkage plate (404) simultaneously lifts up to release the air cylinder (403). A negative pressure is formed inside the air cylinder (403), and external air is replenished into the air cylinder (403) through the air inlet pipe.

4. The hot extrusion apparatus for duplex steel bars according to claim 1, characterized in that: The extension end of the second servo hydraulic cylinder (209) is fixedly connected to an advanced push plate (210). The advanced push plate (210) has a sliding through hole (211) that matches the push rod (208). The advanced push plate (210) is slidably connected to the surface of the push rod (208) through the sliding through hole (211). The sliding through hole (211) provides a sliding guide for the advanced push plate (210) to ensure that the extrusion pressure is output coaxially and stably. The push rod (208) passes through the sliding through hole (211) to form a coaxial limiting guide pair. The inner wall of the sliding through hole (211) and the outer wall of the push rod (208) are fitted together to constrain the advanced push plate (210) to slide linearly along the axial direction of the push rod (208). The center of the advanced push plate (210) is rigidly fixed to the tail of the extrusion rod (206). The first servo hydraulic cylinder (207) first pushes the push rod (208) and the extrusion sleeve (205) to move forward as a whole to cover the blank in the mold heating sleeve (202) and complete the outer perimeter limiting and sealing of the blank. Then, the second servo hydraulic cylinder (209) outputs thrust to drive the advanced push plate (210) to slide forward along the push rod (208). The advanced push plate (210) pushes the extrusion rod (206) to apply extrusion pressure to the constant temperature blank. The sliding through hole (211) restricts the radial displacement of the advanced push plate (210) throughout the process. The extrusion pressure is evenly transmitted to the blank along the central axis.

5. The hot extrusion apparatus for duplex steel bars according to claim 1, characterized in that: A drive motor (212) is fixedly mounted on the surface of the second support frame (102), and a drive gear (213) is fixedly mounted on the output end of the drive motor (212). Support shafts (214) are coaxially fixed on both the left and right sides of the turntable heating seat (201), and driven gears (215) are fixedly mounted on the surface of the support shafts (214). The gear meshing structure realizes the indexing and rotation of the turntable heating seat (201) and the switching of the heating and extrusion station. The drive gear (213) and driven gear (215) constitute a precision gear indexing transmission pair. The two support shafts (214) are mounted on the first support frame (101) and the second support frame (102) through bearings, forming a horizontal coaxial support for the turntable heating seat (201). After the extrusion of a single bar is completed, the extrusion sleeve (205) is completely retracted, and the jet assembly (4) completes the slag removal process, the drive motor (212) starts and drives the drive gear (213) to mesh with the driven gear (215) to rotate the support shaft (214) synchronously, driving the turntable heating seat (201) to rotate at a fixed angle, and precisely switching the mold heating sleeve (202) that has completed constant temperature preheating inside to the extrusion station coaxial with the extrusion sleeve (205), while rotating the empty mold heating sleeve (202) to the outer loading station.

6. The hot extrusion apparatus for duplex steel bars according to claim 5, characterized in that: The mold heating sleeve (202) has a feed port (216) and a discharge hole (217). The extrusion sleeve (205) can slide into the mold heating sleeve (202). The discharge hole (217) limits the outer diameter of the bar forming and is suitable for extrusion of duplex steel bars. The feed inlet (216), discharge hole (217), extrusion sleeve (205), and extrusion bar (206) are arranged coaxially. The diameter of the discharge hole (217) is smaller than that of the feed inlet (216), forming a diameter-reducing forming cavity. After the turntable heating seat (201) drives the mold heating sleeve (202) to the extrusion station, the billet is placed in the feed inlet (216) for constant temperature preheating. The first servo hydraulic cylinder (207) pushes the extrusion sleeve (205) to fully extend into the mold. The heating jacket (202) closes the feed inlet (216) to maintain the overall uniform temperature of the billet; the second servo hydraulic cylinder (209) drives the extrusion bar (206) to push the billet forward, and the high-temperature plastic metal flows along the inner cavity of the mold heating jacket (202) to the discharge hole (217). The inner wall of the discharge hole (217) restricts the outer diameter of the metal flow, and the dual-phase steel bar is extruded in one go. The formed steel bar is directly and continuously transported from the discharge hole (217) to the rear cooling mechanism (3).

7. The hot extrusion apparatus for duplex steel bars according to claim 1, characterized in that: The cooling mechanism (3) includes two crossbars (301) with two electric telescopic rods (302). The telescopic ends of the two electric telescopic rods (302) are fixed with a U-shaped frame (303). A rotating support cylinder (304) is rotatably arranged on the inner side of the U-shaped frame (303). The surface of the rotating support cylinder (304) has several strip-shaped water permeable holes (305). The strip-shaped water permeable holes (305) allow the cooling water to contact the rod material in all directions. The two side crossbars (301), electric telescopic rods (302), and the C-shaped frame (303) form an opening and closing clamping mechanism. After the two sets of C-shaped frames (303) are put together, they form a complete cylindrical cavity. The rotating support cylinder (304) is rotated and assembled on the inner cylinder seat of the C-shaped frame (303). Before the high-temperature steel bar is sent out from the discharge hole (217), the electric telescopic rods (302) on both sides extend synchronously to push the C-shaped frame (303) to close in opposite directions, clamping the rotating support cylinder (304) to form a closed cooling channel. The cooling water sprayed from above falls vertically through the strip-shaped water-permeable hole (305) and directly wets the entire circumferential surface of the steel bar inside the cylinder, ensuring a uniform cooling rate.

8. The hot extrusion apparatus for duplex steel bars according to claim 7, characterized in that: A rotary motor (306) is fixed to the right end of the shaped frame (303). The rotary motor (306) is used to drive the rotary support cylinder (304) to rotate on the surface of the shaped frame (303). The rotary support cylinder (304) is used to drive the steel bar to rotate. The output shaft of the rotary motor (306) is rigidly connected to the rotary support cylinder (304) to form a workpiece rotation drive pair. The rotary support cylinder (304) clamps the steel bar and rotates synchronously. When the cooling water is continuously sprayed downward, the rotary motor (306) drives the rotary support cylinder (304) to rotate at a uniform low speed, which drives the internal high-temperature steel bar to rotate 360° in a circumferential direction, so that the various sides of the steel bar alternately contact the sprayed cooling water.

9. The hot extrusion apparatus for duplex steel bars according to claim 8, characterized in that: The cooling mechanism (3) also includes a horizontal hanger (307) and a conveyor table (308) fixed on the right side of the second support frame (102). An arc-shaped nozzle (309) is fixedly installed on the lower surface of the horizontal hanger (307). A conveyor roller (311) is rotatably arranged on the conveyor table (308), and the conveyor roller (311) receives the cooled bar. The horizontal boom (307) suspends multiple sets of arc-shaped nozzles (309) to form a full-area spray water supply mechanism. The arc-shaped nozzles (309) are arranged downwards at an angle to form a continuous water curtain that provides continuous cooling water. The conveyor platform (308) and multiple parallel conveyor rollers (311) constitute an automatic finished product conveying mechanism. After the steel bar is cooled to the specified process temperature, the electric telescopic rods (302) on both sides retract synchronously to pull the shaped frame (303) apart. The rotating support cylinder (304) separates and releases the steel bar along with the shaped frame (303). The cooled and formed duplex steel bar falls to the surface of the conveyor roller (311) by its own weight and is continuously conveyed and collected by the rolling of the conveyor roller (311).

10. A hot extrusion process for duplex steel bars, used to implement the hot extrusion apparatus for duplex steel bars according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Before starting the equipment, put the biphase steel billet into the mold heating sleeve (202) of the turntable heating seat (201) through the feed port (216); drive motor (212) drives the turntable heating seat (201) to rotate in sections, and rotate the mold heating sleeve (202) carrying the billet to the coaxial position with the extrusion sleeve (205); S2. After preheating is completed, the first servo hydraulic cylinder (207) pushes the extrusion sleeve (205) to cover the billet, and the second servo hydraulic cylinder (209) drives the extrusion bar (206) to apply pressure, and the billet is extruded from the discharge hole (217) to form a shape; S3. The extrusion sleeve (205) retracts and resets, and the U-shaped linkage plate (404) is pulled synchronously to compress the air cylinder (403). The high-pressure airflow passes through the pipe route and blows the sleeve waste residue through the jet nozzle (402). S4. The high-temperature bar is fed into the rotating support cylinder (304) and rotated and sprayed with water for cooling; after cooling, the electric telescopic rod (302) separates the shaped frame (303), and the workpiece falls onto the conveyor roller (311) and is sent out.

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