High-strength stainless steel, manufacturing method and system thereof

Abstract

The invention discloses a high-strength stainless steel, a manufacturing method and a system thereof, and relates to the technical field of stainless steel manufacturing, comprising the following steps: S1: raw material mixing, S2: pressure forming, S3: preheating and conveying, S4: sintering and forming, and S5: cooling post-processing. A sintering control component is installed on the top surface of a base, an electric heating pipe is inlaid on one end of a baffle frame, an air cooling pipe is welded through a first sealed box aligned with the electric heating pipe, a water cooling pipe is installed through a side of a second sealed box aligned with the air cooling pipe, and a conveying and heat preservation component is installed on one side of the base. In the sintering process of the invention, nitrogen is fed into a three-way nitrogen pipe and sprayed to a wheel fan box position close to a hollow round box, the nitrogen will push the wheel fan box to rotate the hollow round box, and then drive the tray to do a circular motion. The moving workpiece makes the sintering temperature of the workpiece on the tray more uniform, and generates chromium nitride with higher strength on the outside of the sintered part to improve the strength of the workpiece, so as to achieve a better sintering effect.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel production, in particular to high-strength stainless steel, a production method and a system thereof. Background Art

[0002] Stainless steel is the abbreviation of stainless acid-resistant steel. Steel that is resistant to weak corrosive media such as air, steam, water, or has stainless properties is called stainless steel, while steel that is resistant to corrosion by chemical corrosive media is called acid-resistant steel. There are many types of stainless steel, which are widely used in life and industrial production. Powder metallurgy belongs to powder sintering technology and is one of the common methods of stainless steel production. Its production efficiency and precision are higher than ordinary metallurgy.

[0003] The patent with application number 202111066852.7 mentions "a sintering furnace and method for controlling the carbon content of stainless steel", which makes it convenient for personnel to stack ceramic plates in the slots and for users to adjust the use of the furnace body. At the same time, the ceramic plates can isolate and adsorb the carbon in the graphite cavity of the material box. When sintering some stainless steels, the carbon content can be controlled at 0.03%-0.04%. However, if there are many workpieces in the furnace during sintering in the above process, the sintering temperature is not uniform enough, which leads to uneven sintering, internal structure, and decreased strength. Each time sintering is performed, the sintered workpiece needs to be taken out and rearranged. The process of taking out and putting in is time-consuming, and the temperature of the sintered parts just taken out is high, which can easily scald the operator and cause a safety accident. Summary of the invention

[0004] The present invention provides a high-strength stainless steel, a manufacturing method and a system thereof, which can effectively solve the problem proposed in the above background technology that if there are many workpieces in the furnace during sintering, the sintering temperature is not uniform, which leads to uneven sintering, internal structure, and reduced strength. Each time sintering is performed, the sintered workpieces need to be taken out and rearranged, and the process of taking out and putting in is time-consuming. The temperature of the sintered parts just taken out is high, which can easily scald the operators and cause safety accidents.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for making high-strength stainless steel, comprising the following steps:

[0006] S1: Raw material mixing: stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid are uniformly mixed according to the proportion;

[0007] S2: Pressing and molding: adding the mixed powder into a mold, and molding it by pressurization to obtain a metal green billet;

[0008] S3: Preheating and conveying: The pressurized stainless steel workpieces are evenly placed on the top surface of the tray of the sliding sintering car, and the sliding sintering car is placed on one end of the top surface of the conveying roller for conveying. The sliding sintering car is gradually preheated when passing near the air cooling pipe and the electric heating pipe;

[0009] S4: Sintering: The electric heating tube gradually heats up to the sintering temperature, nitrogen is fed into the three-way nitrogen pipe, and the hollow round box rotates to make the sintering temperature of the workpiece on the tray uniform. The chromium in the workpiece will react under high temperature and high pressure to form a chromium nitride film;

[0010] S5: Post-cooling treatment: After air cooling, the sliding sintering car enters the water cooling pipe to spray water for cooling. According to the needs, the stainless steel workpiece after sintering and cooling is sandblasted, polished and coated with a protective layer to complete the production of stainless steel sintered parts.

[0011] According to the above technical solution, the mass percentages of the stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid in S1 are 87.1% to 90.2%, 1.5% to 3%, 5% to 10% and 2% to 5%, respectively.

[0012] According to the above technical solution, the stainless steel powder in S1 is a mixture of iron powder, chromium powder and nickel powder, all of which are high-purity metal powders with a purity higher than 99.9%. The mass percentages of iron powder, chromium powder and nickel powder in the stainless steel powder are 70% to 78%, 15% to 20% and 10% to 12% respectively. The particle size of silicon carbide powder is 10 to 44 μm. The sintering activation aid is Fe2Mo2B powder with a particle size of 5 to 10 μm.

[0013] According to the above technical solution, the pressurization pressure in S2 is 300-500 MPa, and the pressurization time is 1.5-3 min.

[0014] According to the above technical solution, a system for making high-strength stainless steel, and a system for making a method for making high-strength stainless steel, a sintering control component is installed on the top surface of the base, and the sintering control component includes an adjustment hole;

[0015] An adjustment hole is provided on one side of the base, a support plate is movably embedded in the top of the adjustment hole, a limit plate is placed in the middle of the bottom end of the adjustment hole, an electromagnet is inlaid in the middle of the top surface of the limit plate, an end support is placed at one end of the adjustment hole, the top of the end support is connected to the bottom surface of the support plate through a hinge, a jack is equidistantly installed at the other end of the adjustment hole, and the top of the extended end of the jack contacts the bottom surface of the support plate;

[0016] A baffle frame is installed on the top surface of the support plate, one end of the baffle frame is inlaid with an electric heating tube, a sliding sintering car is placed inside the electric heating tube, two ends of the top surface of the sliding sintering car are respectively rotatably clamped with two ends of the shaft rod, both ends of the shaft rod are fixedly sleeved with hollow round boxes, wheel fan boxes are evenly penetrated and installed on the outside of the hollow round box, an air inlet hole is opened in the middle of one side of the wheel fan box, an air supply pipe is distributed in a circular array between the two hollow round boxes, both ends of the air supply pipe are rotatably sleeved with hollow hanging rods, the air supply pipe is provided with a connecting hole at the hollow hanging rod corresponding to the hollow hanging rod, and the two ends of the two hollow hanging rods at the same height are respectively connected to the two ends of the tray An air-distributing groove is provided in the middle of the top surface of the tray, and grille bars are inlaid inside the air-distributing groove. A first sealing box is fixedly welded to one end of the electric heating tube, and an air-cooling tube is welded through the first sealing box aligned with the electric heating tube. A three-way nitrogen pipe is installed through the middle of the electric heating tube and the air-cooling tube, a second sealing box is fixedly welded to one end of the air-cooling tube, and a water-cooling pipe is installed through the side of the second sealing box aligned with the air-cooling pipe, an exhaust pipe is installed through the electric heating tube and the air-cooling tube away from the three-way nitrogen pipe, an electric-controlled valve is installed at one end of the exhaust pipe, and a three-way water-cooling nozzle is installed through the middle of the water-cooling tube.

[0017] According to the above technical solution, a driving motor is installed at the bottom end of the first sealed box and the second sealed box, the output shaft end of the driving motor passes through the first sealed box and the second sealed box and is connected to a screw rod, an internal threaded tube is threadedly sleeved on the outside of the screw rod, the internal threaded tube is fixedly penetrated through the bottom end of the heat-insulating drawer plate, an insulation frame is sleeved on the outside of the insulation drawer plate, and a transposition hole is opened in the middle of the insulation frame.

[0018] According to the above technical solution, both ends of the three-way nitrogen pipe are respectively aligned with the hollow round boxes at both ends of the same sliding sintering car, and the other end of the three-way nitrogen pipe is connected to the nitrogen pump.

[0019] According to the above technical solution, a conveying and heat-insulating component is installed on one side of the base, and the conveying and heat-insulating component includes a feeding plate rack;

[0020] A feeding plate rack is placed at one end of the electric heating tube, a lifting groove is provided on the top surface of the feeding plate rack, a lifting plate is movably embedded in the lifting groove, an introduction groove is symmetrically provided on the top surface of the lifting plate, a lifting electric push rod is installed on the bottom surface of the feeding plate rack, the extended end of the lifting electric push rod passes through the bottom end of the introduction groove and is connected to the lifting plate, one end of the feeding plate rack is connected to a conveying roller, a heat insulation cover is connected to the outer surface of the conveying roller, a delivery hole is provided at one end of the heat insulation cover corresponding to the feeding plate rack, a multi-stage electric push rod is installed at one side of the heat insulation cover corresponding to the delivery hole, and the extended end of the multi-stage electric push rod passes through the heat insulation cover and is connected to a buffer push plate;

[0021] Horizontal pushing electric push rods are installed at the top of the heat insulation cover aligned with the middle part of the electric heating tube and the air cooling tube, the extended end of the horizontal pushing electric push rod is connected to the middle part of the straight plate, the two ends of the straight plate are respectively connected to the heat insulation partition, the heat insulation partition movably passes through the side feeding plate frame of the heat insulation cover, and a loading electric push rod is installed in the middle part of one side, and the exhaust pipe movably passes through the side of the heat insulation cover.

[0022] According to the above technical scheme, the input ends of the electromagnet, jack, electric heating tube, electric control valve, nitrogen pump, lifting electric push rod, multi-stage electric push rod, horizontal pushing electric push rod and loading electric push rod are electrically connected to the output end of the external controller respectively, and the input end of the external controller is electrically connected to the output end of the external power supply.

[0023] According to the above technical solution, a high-strength stainless steel is provided, and the stainless steel is manufactured according to a method for manufacturing high-strength stainless steel.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. A sintering control component is provided. During the sintering process, nitrogen is fed into the three-way nitrogen pipe and sprayed to the position of the wheel fan box close to the hollow round box. The nitrogen will push the wheel fan box to make the hollow round box rotate, and then drive the tray to make a circular motion. The moving workpiece makes the sintering temperature of the workpiece on the tray more uniform;

[0026] Another part of nitrogen will enter the hollow round box, air supply pipe, hollow hanging rod and air balancing slot in sequence through the air inlet hole, and finally be ejected from the grid bar to the surface of the sintered workpiece. Due to the continuous input of nitrogen, the chromium in the workpiece will react under the conditions of high temperature and high pressure to form a chromium nitride film on the outside of the workpiece, making the heat more evenly distributed on the outside of the sintered part, and generating stronger chromium nitride on the outside of the sintered part to improve the strength of the workpiece and achieve better sintering effect.

[0027] After sintering is completed, the screw rotates in the internal threaded tube and drives the insulation drawer plate to move out of the insulation frame. The sliding sintering car in the electric heating tube slides along the bottom surface of the electric heating tube and enters the air cooling tube. The three-way nitrogen pipe blows air to the sliding sintering car in the air cooling tube. While the air cooling operation is being performed, the green embryo can be sent into the electric heating tube for sintering. Compared with the process of taking out the sintered workpiece and then rearranging it, the operation is more time-saving and improves the sintering efficiency.

[0028] Stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid are evenly mixed in proportion. Silicon carbide powder improves the overall strength. After sintering, due to the different materials and the decomposition of some materials at high temperatures, many gaps will appear in the extruded green workpiece. During the sintering nitrogen introduction process, nitrogen will enter the gaps and form chromium nitride in the gaps, further improving the strength of the stainless steel workpiece after forming.

[0029] 2. A conveying and heat preservation component is provided. The pressurized stainless steel workpieces are evenly placed on the top of the tray of the sliding sintering car. After being transported by the conveying roller, the sliding sintering car moves to the delivery hole. The buffer push plate pushes the sliding sintering car to the top of the lifting plate of the feeding plate rack. The loading electric push rod pushes the sliding sintering car into the electric heating tube.

[0030] In the process of re-conveying the sliding sintering car, the two horizontal push electric push rods are in the extended state, pushing the straight plate to push the heat insulation partition out of the heat insulation cover, and the heat insulation cover is in a fully connected state. When the sliding sintering car on the conveying roller passes near the air cooling pipe, the hot air blown out of the exhaust pipe of the air cooling pipe will preheat the sliding sintering car. Similarly, when the sliding sintering car on the conveying roller passes near the electric heating pipe, the hot air blown out of the exhaust pipe of the electric heating pipe will preheat the sliding sintering car again. After multiple stages of preheating, the sliding sintering car will reach the sintering temperature faster when it enters the electric heating pipe for sintering, further accelerating the sintering efficiency.

[0031] In summary, the high-temperature air ejected by the sintering control component is used for preheating operation during the conveying process of the insulation component. The two components cooperate with each other, combined with continuous preheating, feeding and sintering operations, which greatly improves the sintering efficiency and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0033] In the attached picture:

[0034] Figure 1 It is a schematic flow diagram of the method of the present invention;

[0035] Figure 2 It is a three-dimensional structural schematic diagram of the present invention;

[0036] Figure 3 is a schematic structural diagram of a sintering control assembly of the present invention;

[0037] Figure 4 It is a schematic diagram of the installation structure of the heat insulation pumping plate of the present invention;

[0038] Figure 5 The present invention Figure 4 Schematic diagram of the A region structure;

[0039] Figure 6 It is a schematic diagram of the installation structure of the air supply pipe of the present invention;

[0040] Figure 7 It is a schematic diagram of the installation structure of the grille bar of the present invention;

[0041] Figure 8 It is a structural schematic diagram of the conveying and heat-insulating assembly of the present invention;

[0042] Fig. 9 It is a schematic diagram of the installation structure of the heat insulation partition of the present invention;

[0043] Fig.10 The present invention Fig. 9 Schematic diagram of the structure of region B;

[0044] Numbers in the figure: 1, base;

[0045] 2. Sintering control assembly; 201. Adjustment hole; 202. Support plate; 203. Limit plate; 204. Electromagnet; 205. End support; 206. Jack; 207. Stop frame; 208. Electric heating tube; 209. Sliding sintering car; 210. Axle rod; 211. Hollow round box; 212. Wheel fan box; 213. Air inlet hole; 214. Air supply pipe; 215. Hollow hanging rod; 216. Connecting hole; 217. Tray; 218, air distribution slot; 219, grille bar; 220, first sealed box; 221, air cooling pipe; 222, three-way nitrogen pipe; 223, second sealed box; 224, water cooling pipe; 225, exhaust pipe; 226, electric control valve; 227, drive motor; 228, screw rod; 229, internal threaded pipe; 230, heat insulation drawer plate; 231, heat insulation frame; 232, transposition hole; 233, nitrogen pump; 234, three-way water cooling nozzle;

[0046] 3. Conveying and heat preservation components; 301. Feeding plate rack; 302. Lifting slot; 303. Lifting plate; 304. Introducing slot; 305. Lifting electric push rod; 306. Heat insulation cover; 307. Delivery hole; 308. Multi-stage electric push rod; 309. Buffer push plate; 310. Horizontal push electric push rod; 311. Straight plate; 312. Heat insulation partition; 313. Loading electric push rod; 314. Conveying roller. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0048] Example: Figure 1 As shown, the present invention provides a method for manufacturing high-strength stainless steel, comprising the following steps:

[0049] S1: Raw material mixing: stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid are uniformly mixed according to the proportion;

[0050] S2: Pressing and molding: adding the mixed powder into a mold, and molding it by pressurization to obtain a metal green billet;

[0051] S3: Preheating and conveying: The pressurized stainless steel workpieces are evenly placed on the top surface of the tray 217 of the sliding sintering car 209, and the sliding sintering car 209 is placed on one end of the top surface of the conveying roller 314 for conveying. The sliding sintering car 209 is gradually preheated when passing near the air cooling pipe 221 and the electric heating pipe 208;

[0052] S4: Sintering: The electric heating tube 208 is gradually heated to the sintering temperature, the three-way nitrogen tube 222 is used to feed nitrogen, and the hollow round box 211 is rotated to make the sintering temperature of the workpiece on the tray 217 uniform. The chromium in the workpiece will react under the conditions of high temperature and high pressure to form a chromium nitride film;

[0053] S5: Post-cooling treatment: After air cooling, the sliding sintering car 209 enters the water cooling pipe 224 to spray water for cooling. The sintered and cooled stainless steel workpiece is sandblasted, polished and coated with a protective layer as needed to complete the production of the stainless steel sintered parts.

[0054] The mass percentages of stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid in S1 are 84.2%, 2.3%, 9.5% and 4%, respectively.

[0055] The stainless steel powder in S1 is a mixture of iron powder, chromium powder and nickel powder, all of which are high-purity metal powders with a purity higher than 99.9%. The mass percentages of iron powder, chromium powder and nickel powder in the stainless steel powder are 71%, 18% and 11% respectively. The particle size of silicon carbide powder is 25 μm. The sintering activation aid is Fe2Mo2B powder with a particle size of 8 μm.

[0056] The pressurization pressure in S2 was 500 MPa, and the pressurization time was 2 min.

[0057] like Figure 2-10 As shown, a high-strength stainless steel production system, a sintering control component 2 is installed on the top surface of the base 1, and the sintering control component 2 includes an adjustment hole 201, a support plate 202, a limit plate 203, an electromagnet 204, an end support 205, a jack 206, a baffle 207, an electric heating pipe 208, a sliding sintering car 209, an axle 210, a hollow round box 211, a wheel fan box 212, an air inlet hole 213, an air supply pipe 214, a hollow hanging rod 2 15, connecting hole 216, tray 217, air balancing slot 218, grille bar 219, first sealed box 220, air cooling pipe 221, three-way nitrogen pipe 222, second sealed box 223, water cooling pipe 224, exhaust pipe 225, electric control valve 226, drive motor 227, screw rod 228, internal threaded pipe 229, heat insulation drawer plate 230, heat insulation frame 231, transposition hole 232, nitrogen pump 233 and three-way water cooling nozzle 234;

[0058] An adjustment hole 201 is provided on one side of the base 1, a support plate 202 is movably embedded in the top of the adjustment hole 201, a limit plate 203 is placed in the middle of the bottom end of the adjustment hole 201, an electromagnet 204 is inlaid in the middle of the top surface of the limit plate 203, an end support 205 is placed at one end of the adjustment hole 201, the top of the end support 205 is connected to the bottom surface of the support plate 202 through a hinge, and a jack 206 is equidistantly installed at the other end of the adjustment hole 201, and the top of the extended end of the jack 206 contacts the bottom surface of the support plate 202;

[0059] A baffle 207 is installed on the top surface of the support plate 202, and an electric heating tube 208 is embedded at one end of the baffle 207. A sliding sintering car 209 is placed inside the electric heating tube 208. The two ends of the top surface of the sliding sintering car 209 are respectively rotatably connected to the two ends of the shaft rod 210. Both ends of the shaft rod 210 are fixedly sleeved with hollow round boxes 211. Wheel fan boxes 212 are evenly installed on the outside of the hollow round box 211. An air inlet hole 213 is opened in the middle of one side of the wheel fan box 212. An air supply pipe 214 is distributed in a circular array between the two hollow round boxes 211. Both ends of the air supply pipe 214 are rotatably sleeved with A hollow hanging rod 215 is provided, and a connecting hole 216 is provided at the air supply pipe 214 corresponding to the hollow hanging rod 215. Two ends of the two hollow hanging rods 215 at the same height are respectively connected to two ends of the tray 217. An air distribution groove 218 is provided in the middle of the top surface of the tray 217. A grille bar 219 is inlaid inside the air distribution groove 218. A first sealing box 220 is fixedly welded to one end of the electric heating pipe 208. An air cooling pipe 221 is welded through the first sealing box 220 aligned with the electric heating pipe 208. A three-way nitrogen pipe 222 is installed through the middle of the electric heating pipe 208 and the air cooling pipe 221. The two ends of the nitrogen pipe 222 are respectively aligned with the hollow round boxes 211 at the two ends of the same sliding sintering car 209, and the other end of the three-way nitrogen pipe 222 is connected to the nitrogen pump 233, so that the three-way nitrogen pipe 222 can blow the hollow round box 211 to make the hollow round box 211 rotate. A second sealed box 223 is fixedly welded to one end of the air cooling pipe 221, and a water cooling pipe 224 is installed through the side of the second sealed box 223 aligned with the air cooling pipe 221. An exhaust pipe 225 is installed through the electric heating pipe 208 and the air cooling pipe 221 away from the three-way nitrogen pipe 222. The exhaust pipe 22 An electric control valve 226 is installed at one end, a three-way water-cooling spray pipe 234 is installed through the middle of the water-cooling pipe 224, a driving motor 227 is installed at the bottom of the first sealed box 220 and the second sealed box 223, the output shaft end of the driving motor 227 penetrates the first sealed box 220 and the second sealed box 223 and is connected to a screw rod 228, an internal threaded pipe 229 is sleeved on the outer side of the screw rod 228 through a thread, the internal threaded pipe 229 is fixedly penetrated through the bottom end of the heat-insulating draw plate 230, a heat-insulating frame 231 is sleeved on the outer side of the heat-insulating draw plate 230, and a transposition hole 232 is opened in the middle of the heat-insulating frame 231.

[0060] A conveying and heat-insulating assembly 3 is installed on one side of the base 1, and the conveying and heat-insulating assembly 3 includes a feeding plate frame 301, a lifting slot 302, a lifting plate 303, an introduction slot 304, a lifting electric push rod 305, a heat insulation cover 306, a delivery hole 307, a multi-stage electric push rod 308, a buffer push plate 309, a horizontal push electric push rod 310, a straight plate 311, a heat insulation partition 312 and a feeding electric push rod 313;

[0061] A feeding plate rack 301 is placed at one end of the electric heating tube 208, and a lifting groove 302 is provided on the top surface of the feeding plate rack 301, and a lifting plate 303 is movably embedded in the lifting groove 302. An introduction groove 304 is symmetrically provided on the top surface of the lifting plate 303, and a lifting electric push rod 305 is installed on the bottom surface of the feeding plate rack 301. The protruding end of the lifting electric push rod 305 passes through the bottom end of the introduction groove 304 and is connected to the lifting plate 303. A conveying roller 314 is connected to one end of the feeding plate rack 301, and a heat insulation cover 306 is connected to the outer shell of the conveying roller 314. A delivery hole 307 is provided on one end of the heat insulation cover 306 corresponding to the feeding plate rack 301, and a multi-stage electric push rod 308 is installed at one side of the heat insulation cover 306 corresponding to the delivery hole 307, and the protruding end of the multi-stage electric push rod 308 passes through the heat insulation cover 306 and is connected to a buffer push plate 309;

[0062] A horizontal push rod 310 is installed at the top of the heat insulation cover 306 aligned with the electric heating tube 208 and the middle of the air cooling tube 221. The extended end of the horizontal push rod 310 is connected to the middle of the straight plate 311. The two ends of the straight plate 311 are respectively connected to the heat insulation partition 312. The heat insulation partition 312 movably penetrates the side of the heat insulation cover 306. A feeding electric push rod 313 is installed in the middle of one side of the feeding plate frame 301. The exhaust pipe 225 movably penetrates the side of the heat insulation cover 306. The electromagnet 204, the jack 206, the electric heating tube 208, the electric The input ends of the control valve 226, the nitrogen pump 233, the lifting electric push rod 305, the multi-stage electric push rod 308, the horizontal pushing electric push rod 310 and the loading electric push rod 313 are electrically connected to the output ends of the external controller respectively, and the input end of the external controller is electrically connected to the output end of the external power supply, to ensure the normal operation of the electromagnet 204, the jack 206, the electric heating tube 208, the electric control valve 226, the nitrogen pump 233, the lifting electric push rod 305, the multi-stage electric push rod 308, the horizontal pushing electric push rod 310 and the loading electric push rod 313.

[0063] A high-strength stainless steel, stainless steel manufactured according to a method for manufacturing high-strength stainless steel.

[0064] The working principle and use process of the present invention are as follows: stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid are uniformly mixed in proportion, the mixed powder is added into a mold, and after being pressurized, a metal green billet is obtained. The pressurized stainless steel workpieces are evenly placed on the top surface of the tray 217 of the sliding sintering car 209, and the sliding sintering car 209 is placed in the middle of the heat insulation cover 306 at one end of the top surface of the conveying roller 314. After being conveyed by the conveying roller 314, the sliding sintering car 209 moves to the delivery hole 307, the multi-stage electric push rod 308 is started, and the buffer push plate 309 pushes the sliding sintering car 209 to move to the top surface of the lifting plate 303 of the feeding plate rack 301, and the sliding sintering car The roller of 209 is embedded in the introduction groove 304 of the lifting plate 303, and the loading electric push rod 313 pushes the sliding sintering car 209 into the electric heating tube 208. The sliding sintering car 209, the shaft rod 210, the hollow round box 211 and the wheel fan box 212 are all made of high-temperature resistant tungsten steel to prevent the sliding sintering car 209 from being damaged by the high temperature during the sintering process. The workpiece to be sintered is transported to the sintering position by using the cooperation of the feeding plate frame 301, the conveying roller 314 and a plurality of electric push rods. The electric heating tube 208, the air supply pipe 214 and the water cooling pipe 224 are all heat-resistant ceramic tubes with rectangular frame end faces installed in the round tube, and the resistance wire is installed in the heat-resistant ceramic tube of the rectangular frame of the electric heating tube 208;

[0065] During the sintering process, the electric heating tube 208 is gradually heated up to the sintering temperature, and the three-way nitrogen pipe 222 is used to feed nitrogen and spray it to the position of the wheel fan box 212 close to the hollow round box 211. Due to the high air flow speed, the nitrogen will push the wheel fan box 212 to make the hollow round box 211 rotate, thereby driving the tray 217 to do a circular motion. The moving workpiece makes the sintering temperature of the workpieces on the tray 217 more uniform. Another part of the nitrogen will enter the hollow round box 211, the air supply pipe 214, the hollow hanging rod 215 and the air balancing slot 218 in sequence through the air inlet hole 213, and finally spray out from the grille bar 219. The chromium in the workpiece will react under the conditions of high temperature and high pressure to form a chromium nitride film on the outside of the workpiece. When the gas pressure in the electric heating tube 208 is too high, the electric control valve 226 of the exhaust pipe 225 of the electric heating tube 208 is opened to exhaust and release pressure to ensure safety. The heat is more evenly distributed on the outside of the sintered part by rotating the sintered part, and chromium nitride with higher strength is generated on the outside of the sintered part to improve the strength of the workpiece, and the sintering effect is better.

[0066] After sintering is completed, heating is stopped. Since the two sides of the heat insulation frame 231 between the electric heating tube 208 and the air cooling tube 221 are in close contact with the electric heating tube 208 and the air cooling tube 221 respectively, and the heat insulation frame 231 is blocked by the heat insulation drawer 230, the electric heating tube 208 is in a closed state, and the sliding sintering car 209 cannot pass through the transposition hole 232, the driving motor 227 is started to drive the screw rod 228 to rotate, and the screw rod 228 rotates in the internal threaded tube 229 and drives the heat insulation drawer 230 to move out. The heat insulation frame 231 opens the transposition hole 232, the electric heating tube 208 is connected to the air cooling tube 221, the electromagnet 204 is powered off, and the support plate 202 is no longer attracted. The jack 206 is started to lift the support plate 202, and the support plate 202 rotates with the top of the limit plate 203 as the fulcrum. The support plate 202 is tilted, and the sliding sintering car 209 in the electric heating tube 208 slides along the bottom surface of the electric heating tube 208 and enters the air cooling tube 221. The heat insulation drawer plate 230 in the heat insulation frame 231 between the air cooling pipes 221 is reset, and the transposition hole 232 is continuously closed, so that the air cooling pipe 221 is in a closed state, and the nitrogen pump 233 corresponding to the air cooling pipe 221 is turned on, and the three-way nitrogen pipe 222 blows air to the sliding sintering car 209 in the air cooling pipe 221. Because the air outlet of the three-way nitrogen pipe 222 is close to the wheel fan box 212, the wheel fan box 212 will be blown to rotate, and the nitrogen will enter the hollow round box 211 and the air supply pipe in sequence through the air inlet hole 213. 214, hollow hanging rod 215 and air distribution slot 218, and finally sprayed from grid bar 219 to the surface of sintered workpiece for cooling, and the electric control valve 226 of exhaust pipe 225 of air cooling pipe 221 is opened to discharge the heated gas for air cooling operation, and while the air cooling operation is being performed, the green blank can be put into electric heating pipe 208 for sintering operation, which is more time-saving and improves the sintering efficiency compared to the process of taking out the sintered workpiece and then rearranging it.

[0067] In the process of re-conveying the sliding sintering car 209, the two horizontal push electric push rods 310 are in an extended state, pushing the straight plate 311 to push the insulation partition 312 out of the insulation cover 306, and the insulation cover 306 is in a fully connected state. When the sliding sintering car 209 on the conveying roller 314 passes near the air cooling pipe 221, the horizontal push electric push rod 310 close to the air cooling pipe 221 pulls the insulation partition 312 into the insulation cover 306, so that the section is closed, and the hot air blown out of the exhaust pipe 225 of the air cooling pipe 221 will preliminarily preheat the sliding sintering car 209 Similarly, when the sliding sintering car 209 of the conveying roller 314 passes near the electric heating tube 208, the hot air blown out of the exhaust pipe 225 of the electric heating tube 208 will preheat the sliding sintering car 209 again, and the hot air temperature blown out of the electric heating tube 208 is higher than the hot air temperature blown out of the air cooling tube 221. After multiple stages of preheating, when the sliding sintering car 209 enters the electric heating tube 208 for sintering, it will reach the sintering temperature more quickly, further accelerating the sintering efficiency. Combined with the continuous preheating, feeding, and sintering operations, the sintering efficiency is greatly improved, and the production efficiency is improved.

[0068] After air cooling, the sliding sintering car 209 enters the water cooling pipe 224 in the same way as the sliding sintering car 209 enters the air cooling pipe 221 from the electric heating pipe 208. The three-way water cooling nozzle 234 sprays water to cool it down, so that the operator can take it out and avoid scalding the operator. Finally, the stainless steel workpiece after sintering and cooling is sandblasted, polished and coated with a protective layer as needed to complete the production of stainless steel sintered parts.

[0069] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for producing high-strength stainless steel, characterized in that: The following steps are involved: S1: Raw material mixing: stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid are uniformly mixed according to the proportion; S2: Pressing and molding: adding the mixed powder into a mold, and molding it by pressurization to obtain a metal green billet; S3: Preheating and conveying: The pressurized stainless steel workpieces are evenly placed on the top surface of the tray (217) of the sliding sintering car (209), and the sliding sintering car (209) is placed on one end of the top surface of the conveying roller (314) for conveying. The sliding sintering car (209) is gradually preheated when passing near the air cooling pipe (221) and the electric heating pipe (208); S4: Sintering: The electric heating tube (208) is gradually heated to the sintering temperature, nitrogen is introduced through the three-way nitrogen tube (222), and the hollow round box (211) rotates, thereby driving the tray (217) to make a circular motion, so that the sintering temperature of the workpiece on the tray (217) is uniform, and the chromium in the workpiece reacts under the conditions of high temperature and high pressure to form a chromium nitride film; S5: post-cooling treatment: after air cooling, the sliding sintering car (209) enters the water cooling pipe (224) and sprays water for cooling. The sintered and cooled stainless steel workpiece is subjected to sandblasting, polishing and coating of a protective layer as required, thereby completing the production of the stainless steel sintered part. The mass percentages of stainless steel powder, silicon carbide powder, ammonium molybdate and sintering activation aid in S1 are 87.1% to 90.2%, 1.5% to 3%, 5% to 10% and 2% to 5% respectively; The stainless steel powder in S1 is a mixture of iron powder, chromium powder and nickel powder, all of which are high-purity metal powders with a purity higher than 99.9%. The mass percentages of iron powder, chromium powder and nickel powder in the stainless steel powder are 70%-78%, 15%-20% and 10%-12% respectively. The particle size of silicon carbide powder is 10-44 μm. The sintering activation aid is Fe2Mo2B powder with a particle size of 5-10 μm.

2. The method for making high-strength stainless steel according to claim 1, characterized in that: The pressurization pressure in S2 is 300-500 MPa, and the pressurization time is 1.5-3 min.

3. A high-strength stainless steel production system, characterized in that: According to a manufacturing system of a manufacturing method of high-strength stainless steel according to any one of claims 1 to 2, a sintering control component (2) is installed on the top surface of the base (1), and the sintering control component (2) comprises an adjustment hole (201); An adjustment hole (201) is provided on one side of the base (1), a support plate (202) is movably embedded in the top of the adjustment hole (201), a limit plate (203) is placed in the middle of the bottom of the adjustment hole (201), an electromagnet (204) is embedded in the middle of the top surface of the limit plate (203), an end support (205) is placed at one end of the adjustment hole (201), the top of the end support (205) is connected to the bottom surface of the support plate (202) through a hinge, and a jack (206) is equidistantly installed at the other end of the adjustment hole (201), the top of the extended end of the jack (206) contacts the bottom surface of the support plate (202); A baffle (207) is installed on the top surface of the support plate (202), and an electric heating tube (208) is embedded at one end of the baffle (207). A sliding sintering vehicle (209) is placed inside the electric heating tube (208). Two ends of the top surface of the sliding sintering vehicle (209) are respectively rotatably connected to two ends of a shaft rod (210), and both ends of the shaft rod (210) are fixedly sleeved with a hollow round box (211), and a wheel fan box (212) is evenly installed on the outside of the hollow round box (211), and an air inlet hole (213) is opened in the middle of one side of the wheel fan box (212), and an air supply pipe (213) is distributed in a circular array between the two hollow round boxes (211). 4), both ends of the air supply pipe (214) are rotatably sleeved with hollow hanging rods (215), and a connecting hole (216) is provided on the air supply pipe (214) corresponding to the hollow hanging rod (215), and the two ends of the two hollow hanging rods (215) located at the same height are respectively connected to the two ends of the tray (217), and an air distribution groove (218) is provided in the middle of the top surface of the tray (217), and a grille bar (219) is embedded in the air distribution groove (218), and a first sealing box (220) is fixedly welded to one end of the electric heating pipe (208), and an air cooling pipe (221) is welded through the first sealing box (220) aligned with the electric heating pipe (208); A three-way nitrogen pipe (222) is installed through the middle of both the electric heating pipe (208) and the air cooling pipe (221); a second sealing box (223) is fixedly welded to one end of the air cooling pipe (221); a water cooling pipe (224) is installed through the side of the second sealing box (223) aligned with the air cooling pipe (221); an exhaust pipe (225) is installed through the electric heating pipe (208) and the air cooling pipe (221) away from the three-way nitrogen pipe (222); an electric control valve (226) is installed at one end of the exhaust pipe (225); and a three-way water cooling nozzle (234) is installed through the middle of the water cooling pipe (224).

4. A high-strength stainless steel production system according to claim 3, characterized in that: A driving motor (227) is installed at the bottom end of the first sealing box (220) and the second sealing box (223); an output shaft end of the driving motor (227) passes through the first sealing box (220) and the second sealing box (223) and is connected to a screw rod (228); an internal threaded tube (229) is connected to the outside of the screw rod (228) via a threaded sleeve; the internal threaded tube (229) is fixedly inserted through the bottom end of the heat-insulating draw plate (230); A heat insulation frame (231) is sleeved on the outer side of the heat insulation drawer plate (230), and a transposition hole (232) is provided in the middle of the heat insulation frame (231).

5. A high-strength stainless steel manufacturing system according to claim 3, characterized in that: Both ends of the three-way nitrogen pipe (222) are respectively aligned with the hollow round boxes (211) at both ends of the same sliding sintering vehicle (209), and the other end of the three-way nitrogen pipe (222) is connected to a nitrogen pump (233).

6. A high-strength stainless steel manufacturing system according to claim 5, characterized in that: A conveying and heat-insulating component (3) is installed on one side of the base (1), and the conveying and heat-insulating component (3) comprises a feeding plate frame (301); A feeding plate frame (301) is placed at one end of the electric heating tube (208), a lifting groove (302) is provided on the top surface of the feeding plate frame (301), a lifting plate (303) is movably embedded inside the lifting groove (302), an introduction groove (304) is symmetrically provided on the top surface of the lifting plate (303), a lifting electric push rod (305) is installed on the bottom surface of the feeding plate frame (301), and the protruding end of the lifting electric push rod (305) passes through the bottom end of the introduction groove (304) and is connected to the lifting plate (303); One end of the feeding plate frame (301) is connected to a conveying roller (314), the outer surface of the conveying roller (314) is connected to a heat insulation cover (306), an end of the heat insulation cover (306) corresponding to the feeding plate frame (301) is provided with a delivery hole (307), a side of the heat insulation cover (306) is provided with a multi-stage electric push rod (308) corresponding to the delivery hole (307), and the protruding end of the multi-stage electric push rod (308) passes through the heat insulation cover (306) and is connected to a buffer push plate (309); A horizontal push electric push rod (310) is installed at the top of the heat insulation cover (306) aligned with the middle of the electric heating tube (208) and the air cooling tube (221); the extended end of the horizontal push electric push rod (310) is connected to the middle of the straight plate (311); the two ends of the straight plate (311) are respectively connected to the heat insulation baffle (312); the heat insulation baffle (312) movably passes through the side feeding plate frame (301) of the heat insulation cover (306); a loading electric push rod (313) is installed in the middle of one side; the exhaust pipe (225) movably passes through the side of the heat insulation cover (306).

7. A high-strength stainless steel manufacturing system according to claim 6, characterized in that: The input ends of the electromagnet (204), the jack (206), the electric heating tube (208), the electric control valve (226), the nitrogen pump (233), the lifting electric push rod (305), the multi-stage electric push rod (308), the horizontal pushing electric push rod (310) and the loading electric push rod (313) are respectively electrically connected to the output end of the external controller, and the input end of the external controller is electrically connected to the output end of the external power supply.

8. A high-strength stainless steel, characterized in that: Stainless steel made according to the method for making high-strength stainless steel according to any one of claims 1-2.

Images