Double vortex quenching equipment

Abstract

The present invention discloses a double vortex quenching equipment, which relates to the technical field of heat treatment devices for spherical and quasi-spherical workpieces, and includes a quenching tank and a medium circulation system; the top of the quenching tank is two cylindrical shell structures arranged to intersect, and the bottom of each cylindrical shell structure is respectively connected to the larger end of a truncated cone shell structure; each cylindrical shell structure is provided with an inlet tangent to the inner wall of the cylindrical shell structure, and the inlet is connected to the medium circulation system. After the medium enters the cylindrical shell structure, a vortex fluid is formed in each cylinder, and the high-speed water flow at the intersection of the double vortex is used to perform quenching heat treatment on the workpiece, and the quenching medium is unimpededly in contact with all parts of the workpiece surface, realizing cooling without dead angles. The flow field in the quenching tank is regular, and the high-speed water flow flows smoothly, while solving the problem of splashing of the quenching medium. There is no need to use a large water tank, which is more suitable for use when the site is limited.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment devices for spherical and quasi-spherical workpieces, in particular to double-vortex quenching equipment. Background Art

[0002] Quenching is a common and important method for strengthening steel materials. The purpose of quenching is to transform the supercooled austenite into martensite or bainite to obtain martensite or bainite structure, so as to greatly improve the strength, hardness, wear resistance, etc. of the material, so as to meet the use requirements of various mechanical parts and tools.

[0003] The rapid cooling process of quenching is generally achieved in a medium, and the commonly used media are water, oil and salt substances. Different media have different cooling rates. According to conventional theory, the greater the cooling rate, the higher the strength and hardness of the workpiece, but the greater the tendency to crack. If water is used as the quenching medium, higher strength and hardness are obtained than using oil as the medium, but the quenching stress is large and the workpiece is prone to deformation and cracking.

[0004] The latest research in recent years shows that the relationship between the cracking tendency and cooling rate during quenching of workpieces is not a simple linear relationship. As the cooling rate increases, the cracking tendency increases first, reaching the highest at 350℃ / s, and the cracking tendency decreases as the cooling rate continues to increase. This is because under the high-speed cooling condition of 350℃ / s, the combination of the surface layer and the internal shrinkage and expansion of the workpiece changes, making the surface layer in a compressive stress state, thereby reducing the cracking tendency, which is the strong quenching effect. Studies have shown that in order to obtain a larger surface compressive stress, the cooling rate should follow the principle of "fast cooling at high temperature and slow cooling at low temperature", first fast and then slow.

[0005] The common strong quenching methods are IQ-2 and IQ-3. The IQ-2 strong quenching method has three steps. The workpiece is first cooled rapidly on the surface by boiling cooling, then slowly cooled in the air, and finally convection cooled in the quenching tank. Compared with the multi-stage cooling IQ-2, the cooling process of IQ-3 is more intense, and the cooling method has only one step, that is, directly forming convection cooling. The high-speed convection heat transfer method enables the workpiece surface to reach a sufficiently fast cooling speed, avoiding the occurrence of steam film cooling and boiling cooling, and putting the surface layer of the workpiece in a compressive stress state, reducing the tendency of cracking, and achieving a strong quenching effect.

[0006] In IQ-3 strong quenching, the cooling rate of the workpiece is an important factor affecting the strong quenching effect, and the quenching medium flow rate directly determines the cooling rate of the workpiece. The faster the flow rate, the faster the cooling, so the quenching medium flow rate is very important. IQ-3 strong quenching requires the medium flow rate on the workpiece surface to reach 2m / s, and the workpiece is quenched without dead angles at the "X" shaped medium flow. At the same time, the splash problem of the quenching medium is completely solved through the design of the cover and anti-splash outlet.

[0007] The patent document with publication number CN106011407A mainly focuses on vacuum water cooling and heat treatment. During quenching, each batch of workpieces is placed in a hanging basket assembly. The next batch can only be processed after the processing is completed. It is processed in batches. During quenching, the workpieces are placed in the hanging basket assembly and sprayed with water by a nozzle. The water is not easy to spray to the place where the workpiece contacts the hanging basket, which will form a cooling dead corner and cause soft spots on the workpiece.

[0008] The patent document with announcement number CN101693942A discloses an intense quenching system with intense stirring in a water tank. The cooling function is achieved by stirring in the water tank. The flow field in the water tank is irregular, and there are dead angles for spherical workpieces. The quenching medium has a high flow rate and is prone to splashing. In order to place the stirring device in the quenching tank, a large water tank must be used. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides an aqueous solution double vortex quenching equipment which can further improve fatigue performance, has high quenching strength and adjustable cooling intensity. The starting point of the equipment design is to be able to form a stable and uniform scouring vortex flow around the workpiece, but the velocity of the center of a single vortex is lower than the velocity of the edge. In order to increase the flow rate of the center medium, the edge velocity must be very high, which will cause a series of problems. The present application designs a double cylinder structure to guide the quenching medium to form a high-speed flowing double vortex in the quenching tank, and utilizes the high-speed water flow at the intersection of the double vortex to form a small, uniform, stable and high-speed circulating flow field around the quenching workpiece that completely wraps the workpiece.

[0010] To achieve the above object, the present invention provides the following solutions:

[0011] The present invention provides a double-vortex quenching device, comprising a quenching tank and a medium circulation system; the top of the quenching tank is two intersecting cylindrical shell structures, and the bottom of each cylindrical shell structure is respectively connected to the larger end of a truncated cone shell structure; each cylindrical shell structure is provided with an inlet tangent to the inner wall of the cylindrical shell structure, and the inlet is connected to the medium circulation system; the medium circulation system is used to provide medium into the quenching tank.

[0012] Optionally, the cylindrical shell structure is further provided with an anti-splash outlet, and the anti-splash outlet is arranged above the inlet.

[0013] Optionally, the axis of the anti-splash outlet intersects with the inner wall of the cylindrical shell structure.

[0014] Optionally, an inlet is respectively provided at both ends of each cylindrical shell structure.

[0015] Optionally, the medium circulation system includes a pump, a flow regulating valve and a medium pool, the pump is arranged between the flow regulating valve and the medium pool, the outlet end of the flow regulating valve is connected to the inlet through a pipeline, and the smaller end of the truncated cone shell structure is connected to the medium pool.

[0016] Optionally, the quenching tank is arranged in the medium pool, and a connecting port is arranged on the medium pool, and the connecting port corresponds to the inlet; an outlet is arranged on one side of the lower part of the medium pool; a baffle is arranged on the top of the medium pool, and the quenching port is arranged in the center of the middle part of the baffle.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The double vortex quenching equipment in the present invention can quench small and medium-sized steel parts, especially workpieces with changing cross-sections, such as spherical and quasi-spherical workpieces. There is no dead angle in quenching, strong stability, controllable speed, and uniform hardening. The hardness and wear resistance of the workpiece are greatly increased, and at the same time, the surface of the workpiece is under compressive stress, which increases fatigue life. The entire system is simple, and the inorganic salt aqueous solution is cheaper than quenching oil, which greatly reduces production costs. At the same time, the inorganic salt aqueous solution is used as the quenching medium to replace the polluted quenching oil to protect the environment.

[0019] The double vortex quenching equipment in the present invention has a quenching tank that can cause the medium to generate a high-speed double vortex flow. The high-speed water flow at the intersection of the double vortices is used to form a small, uniform, stable, and high-speed circulating flow field around the workpiece that completely wraps the workpiece, so as to perform quenching heat treatment on the workpiece. There are no fixtures or bottom plates that can block the impact of the water flow and generate cooling dead corners. The quenching medium can contact all parts of the workpiece surface without hindrance, thereby achieving cooling without dead corners.

[0020] The double vortex quenching equipment in the present invention guides the quenching medium to flow stably and at high speed in the quenching tank through a special structure. The flow field in the quenching tank is regular, and the high-speed water flow flows smoothly. At the same time, the splashing problem of the quenching medium is completely solved through the design of the cover and the anti-splashing outlet. There is no need to use a large water tank, which is more suitable for use when the space is limited. The double vortex quenching equipment in the present invention can also adapt to the production line, and can be produced in single pieces or in batches. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic diagram of the "X"-shaped flow field when there is no workpiece in the quenching tank;

[0023] Figure 2 Schematic diagram of the circulation flow field when there is a workpiece in the quenching tank

[0024] Figure 3 It is a system schematic diagram of the double vortex quenching equipment in the present invention;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the double vortex quenching equipment in the present invention;

[0026] Figure 5 This is a view of the water outlet direction of the double vortex quenching device in the present invention;

[0027] Figure 6 It is a schematic diagram of the three-dimensional structure of the quenching tank of the double vortex quenching equipment in the present invention;

[0028] Figure 7 A side view of a quenching tank of a double vortex quenching device in the present invention;

[0029] Figure 8 It is a schematic cross-sectional diagram of the flow field around a quenching workpiece of the double vortex quenching equipment of the present invention;

[0030] Fig. 9 This is a metallographic structure photograph of a sample subjected to intense quenching by the double vortex quenching equipment of the present invention.

[0031] Explanation of the reference numerals: 1. medium pool; 12. inlet; 13. quenching port; 14. outlet; 15. cover; 2. quenching tank; 21. quenching tank inlet; 22. splash-proof outlet; 23. bracket; 24. quenching tank upper outlet; 25. quenching tank lower outlet; 26. truncated cone-shaped surface; 3. pump; 4. pipeline; 5. flow regulating valve; a. workpiece position. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] like Figures 1 to 7As shown, this embodiment provides a double-vortex quenching equipment, including a quenching tank 2 and a medium circulation system; the top of the quenching tank 2 is two intersecting cylindrical shell structures, and the bottom of each cylindrical shell structure is respectively connected to the larger end of a truncated cone shell structure; each cylindrical shell structure is provided with an inlet 12 tangent to the inner wall of the cylindrical shell structure, and the inlet 12 is connected to the medium circulation system; the medium circulation system is used to provide medium to the quenching tank 2.

[0034] In this specific embodiment, an inlet 12 is provided at each end of each cylindrical shell structure. The inlets 12 are all tangent to the inner wall of the cylindrical shell structure, so that the medium entering the cylindrical shell structure from the four inlets 12 can flow along the inner wall of the cylindrical shell structure, forming a vortex in the cylindrical shell structure, and then forming an X-shaped medium flow at the intersection of the two cylindrical shell structures. The workpiece falls vertically from the quenching port 13 and falls into the X-shaped medium flow for quenching. The principle that the speed of the outer circle of the vortex is greater than the speed of other parts of the vortex is used. A small uniform and stable circulating flow field that completely wraps the workpiece with a speed of more than 2m / s is generated at the intersection of the double vortices, so that the workpiece is quenched in all directions without dead ends.

[0035] Furthermore, the cylindrical shell structure is also provided with an anti-splash outlet 22, which is arranged above the inlet 12. One end of the anti-splash outlet 22 is located above the inlet 12, and the other end is connected to the medium pool 1. The anti-splash outlet can effectively slow down the splash of the medium at the outlet 24 of the quenching tank, thereby preventing the flow turbulence of the medium in the quenching tank 2 caused by a large amount of splash rebound.

[0036] The axis of the anti-splash outlet intersects the inner wall of the cylindrical housing structure.

[0037] In a further specific embodiment, the medium circulation system includes a pump 3, a flow regulating valve 5 and a medium pool 1, wherein the pump 3 is disposed between the flow regulating valve 5 and the medium pool 1, the outlet 14 end of the flow regulating valve 5 is connected to the inlet 12 through a pipeline 4, and the smaller end of the truncated cone-shaped shell structure is connected to the medium pool 1. By controlling the flow regulating valve 5, the flow rate and flow velocity of the medium can be changed, thereby controlling the quenching intensity.

[0038] The double vortex quenching equipment also includes a medium pool 1, the quenching tank 2 is arranged in the medium pool 1, and a connection port is arranged on the medium pool 1, and the connection port corresponds to the inlet 12; a baffle 15 is arranged on the top of the medium pool 1, and the quenching port 13 is arranged on the baffle 15, and the quenching port 13 is located just above the middle of the quenching tank 2. The baffle 15 can prevent the medium from splashing at the outlet 24 on the quenching tank, ensuring that the medium will not splash outside the medium pool 1 of the quenching equipment, ensuring the safety of the quenching heat treatment experiment. A bracket 23 is arranged inside the medium pool 1, and the quenching tank 2 is arranged on the bracket 23.

[0039] An outlet 14 is disposed on one side of the lower portion of the medium pool 1 .

[0040] Combination Figure 8 , simulating the flow field distribution during quenching of spherical and quasi-spherical workpieces, where the medium flow velocity on the workpiece surface is about 2m / s, the flow field is strong and stable, and the speed is controllable, so the workpiece is quenched without dead angles.

[0041] During use, the pump 3 delivers the medium in the medium pool 1 to the inlet 12 of the quenching tank 2 through the pipeline 4. The medium forms an intersecting double vortex flow mode under the action of the double cylinder and the truncated cone surface 26 and forms an "X"-shaped flow mode in the quenching tank 2. A part of the medium falls into the medium pool 1 from the lower outlet 25 of the quenching tank, a part of the medium splashes out from the upper outlet 24 of the quenching tank, hits the inside of the quenching equipment cover 15 and falls into or flows into the medium pool 1, and the remaining part of the medium flows out from the anti-splash outlet 22 and falls into the medium pool 1. The pump 3 delivers the medium into the quenching tank 2 to form a medium circulation. The workpiece to be quenched passes vertically through the quenching port 13 and is immersed in the "X"-shaped geometric center of the intersection of the double vortex medium flow formed by the upper outlet 24 of the quenching tank for rapid cooling. The cooling rate is high, and the workpiece is taken out vertically after the cooling is completed. A quenching process is completed.

[0042] The quenching process is:

[0043] The quenching medium used a sodium chloride solution with a mass fraction of about 11%, and the experiment was carried out at room temperature. The workpiece was ductile iron with a length × width × height of 15 mm × 15 mm × 15 mm, and the composition (w%) was: C 2.62, Si 3.43, Mn 0.182;

[0044] Quenching: the workpiece is heated to 880° C. and kept at that temperature for 10 minutes, and then quenched in the aqueous solution quenching process equipment of the present invention.

[0045] Fig. 9 This is a metallographic structure photograph of the strongly quenched sample with a magnification of 400 times. At this time, it can be seen that the existence of graphite has not been changed after quenching and still exists in a spherical shape.

[0046] After quenching, the hardness of ductile iron was measured to be HRC65, which is about 2 times higher than the original hardness of the sample HRC21, and is also much higher than the hardness index of HRC40 of salt bath quenched austempered ductile iron.

[0047] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0048] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. Double vortex quenching equipment, characterized in that, It includes a quenching tank and a medium circulation system; the top of the quenching tank is two intersecting cylindrical shell structures, and the bottom of each cylindrical shell structure is connected to the larger end of a truncated cone shell structure; each cylindrical shell structure is provided with an inlet tangent to the inner wall of the cylindrical shell structure, and the inlet is connected to the medium circulation system; the medium circulation system is used to provide medium into the quenching tank to form an X-shaped medium flow at the intersection of the double vortices.

2. The double vortex quenching equipment according to claim 1, characterized in that: The cylindrical shell structure is also provided with an anti-splash outlet, and the anti-splash outlet is arranged above the inlet.

3. The double vortex quenching equipment according to claim 2, characterized in that: The axis of the anti-splash outlet intersects the inner wall of the cylindrical housing structure.

4. The double vortex quenching equipment according to claim 1, characterized in that: An inlet is respectively disposed at both ends of each cylindrical shell structure.

5. The double vortex quenching equipment according to claim 1, characterized in that: The medium circulation system includes a pump, a flow regulating valve and a medium pool. The pump is arranged between the flow regulating valve and the medium pool. The outlet end of the flow regulating valve is connected to the inlet through a pipeline, and the smaller end of the truncated cone shell structure is connected to the medium pool.

6. The double vortex quenching equipment according to claim 5, characterized in that: The quenching tank is arranged in the medium pool, and a connecting port is arranged on the medium pool, and the connecting port corresponds to the inlet; an outlet is arranged on one side of the lower part of the medium pool; a baffle is arranged on the top of the medium pool, and the quenching port is arranged at the center of the middle part of the baffle.

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