A casting tray for a chamber furnace

Abstract

The application provides a casting material tray for a chamber furnace, and the casting material tray for the chamber furnace comprises four square sub-material trays with consistent structures which are spliced to form a square material tray body; the sub-material tray comprises a frame and supporting ribs, the supporting ribs are vertically arranged in a hollow cylinder column shape, a plurality of the supporting ribs are closely connected with each other and arranged in a matrix in the frame; two adjacent supporting ribs share a side; the frame side is provided with a jack; and the unique structure of the supporting ribs is closely connected on the basis of the column shape, so that the strength of the material tray is improved, the material tray can bear the press parts at high temperature without deformation and cracking, the reasonable element ratio can effectively strengthen the strength of the material tray, and the dissipation of the thermal stress in the quenching process of the bearing workpiece can be effectively met, so that the deformation and cracking of the material tray which affect the use effect are avoided.

Description

Technical Field

[0001] This invention relates to the field of heat treatment tooling, and more particularly to a casting tray for a chamber furnace. Background Technology

[0002] The chamber furnace heat treatment fixture is designed for a maximum operating temperature of 960℃ and a design load of 20T. The operating environment for the pallet is as follows: the chamber furnace is heated to 960℃, at which point the temperature of the pallet and the workpiece it carries is approximately 960℃. After the workpiece is removed from the pallet by a forklift, it is rapidly cooled in water. While the strength and hardness of the pallet are significantly improved after quenching, its plasticity and toughness are significantly reduced. Rapid cooling generates significant internal stress within the fixture, easily leading to deformation and cracking. Analysis of the pallet's operating environment reveals two technical deficiencies in the existing fixture: firstly, the design of the pallet to bear the corresponding 20T workpiece load at 960℃ has load-bearing limitations; secondly, the dissipation of thermal stress during the workpiece quenching process causes deformation and cracking of the pallet, affecting its performance. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a casting tray for chamber furnaces.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A casting tray for a chamber furnace comprises four identical square sub-traces joined together to form a square tray body.

[0006] The sub-material tray includes a frame and supporting ribs. The supporting ribs are arranged vertically in the shape of hollow cylindrical columns. Several supporting ribs are closely connected to each other and arranged in a matrix within the frame.

[0007] Two adjacent support ribs share a common side;

[0008] The side of the frame is provided with a socket.

[0009] The unique support rib structure, based on the columnar structure, is tightly connected, which enhances the strength of the material tray and allows it to bear the pressure of the components at high temperatures without deformation or cracking.

[0010] Furthermore, the supporting rib is cylindrical in shape and has eight reinforcing concave edges that are evenly distributed on the edge, with a connecting edge between two reinforcing concave edges. Adjacent supporting ribs are connected to each other by sharing a connecting edge. Four adjacent supporting ribs form a "four-pointed star" shape.

[0011] The support rib structure was further improved in the cylindrical form. The design of the concave edge not only enhances the compressive strength of the support rib, but also allows the support rib to be arranged more closely within the frame, so that the support rib and any position of the support rib connection have good support characteristics when subjected to pressure.

[0012] Furthermore, the frame and support ribs have consistent and uniform wall thickness, ensuring uniform cooling rate of each part, which can effectively reduce stress, deformation and cracking, and prevent metal accumulation (heat spots) from causing shrinkage cavities.

[0013] Furthermore, the supporting ribs set close to the inner wall of the frame are half of the complete supporting ribs, ensuring the compressive strength of the material tray edge.

[0014] Furthermore, on one side of the frame, at the quarter-point on both sides, there are "Ω"-shaped connecting ears respectively. The connecting ears are placed inside one-half of the support rib and connected to the frame. When the sub-material trays are spliced ​​together, the opening positions of the two connecting ears correspond and form a reinforcing ear, which facilitates the connection between the material trays and also strengthens the strength of the connection between the material trays.

[0015] Furthermore, one side of the frame is divided into three sections using the connecting ears as the dividing unit, and each section is provided with at least two sets of two rows of sockets, which are evenly distributed.

[0016] Furthermore, the four corners of the frame are rounded. This rounded corner design can prevent the formation of hot spots, improve stress distribution, avoid the formation of pinholes, and effectively reduce the generation of shrinkage cavities.

[0017] Furthermore, the sub-plate is integrally formed and cast using a wax mold precision casting method, increasing the smoothness of the product surface. This adjustment effectively prevents external elements from seeping into the plate during use, especially some harmful elements during the quenching process.

[0018] Furthermore, the sub-material trays are fixed together by screw welding.

[0019] Furthermore, the chemical composition of the material of the feed tray includes the following elements by weight percentage: carbon (C) 0.1-0.2%, chromium (Cr) 24-27%, nickel (Ni) 19-22%, tungsten (W) 2.5-3.5%, cobalt (Co) 1.0-2.0%, niobium (Nb) 0.5-1.0%, sulfur (S) < 0.035%, and phosphorus (P) < 0.035%.

[0020] A reasonable element ratio can effectively enhance the strength of the tray and effectively dissipate the thermal stress of the workpiece during the cold extraction process, ensuring that the tray will not deform or crack, affecting its performance.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) The unique support rib structure is tightly connected on the basis of the column structure, which improves the strength of the material tray and can bear the pressure of the workpiece at high temperature without deformation and cracking; (2) The reasonable element ratio can effectively strengthen the strength of the material tray, and can effectively meet the heat stress dissipation of the workpiece during the quenching process in the cold extraction process, ensuring that the material tray will not deform or crack, which will affect the use effect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall material tray body according to Embodiment 1 of the present invention;

[0023] Figure 2 This is a partial enlarged view of the sub-material tray and connection point in Embodiment 1 of the present invention;

[0024] Figure 3 This is a side view of Embodiment 1 of the present invention;

[0025] Figure 4 This is a schematic diagram of the results under the load-bearing strength boundary conditions in Embodiment 1 of the present invention;

[0026] Figure 5 This is a schematic diagram of the results under the quenching boundary conditions in Embodiment 1 of the present invention;

[0027] Figure 6 This is a schematic diagram of the finite element subdivision of the simulation model in Embodiment 1 of the present invention;

[0028] Figure 7 This is a top view of the load-bearing strength simulation results of Embodiment 1 of the present invention;

[0029] Figure 8 This is a bottom schematic diagram of the load-bearing strength simulation results of Embodiment 1 of the present invention;

[0030] Figure 9 This is a schematic diagram of the deformation displacement distribution of the material tray in Embodiment 1 of the present invention;

[0031] Figure 10 This is a schematic diagram of stress distribution in Embodiment 1 of the present invention;

[0032] Figure 11 This is a schematic diagram of the deformation displacement distribution in Embodiment 1 of the present invention;

[0033] Labeling explanation: 1. Material tray body, 2. Sub-material tray, 21. Frame, 22. Support rib, 221. Reinforcing concave edge, 222. Connecting edge, 223. Connecting ear, 224. Reinforcing ear. Detailed Implementation

[0034] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0035] Example 1, such as Figures 1-3 As shown, a casting tray for a chamber furnace includes four identical square sub-traps 2 joined together to form a square tray body 1.

[0036] The sub-material tray 2 includes a frame 21 and a support rib 22. The support rib 22 is a hollow cylindrical column that is vertically arranged. Several support ribs 22 are closely connected to each other and arranged in a matrix within the frame 21.

[0037] Two adjacent support bars 22 share a side;

[0038] A socket is provided on the side of frame 21.

[0039] The unique support rib 22 structure is tightly connected to the columnar structure, which enhances the strength of the material tray and allows it to bear the pressure of the parts at high temperatures without deformation or cracking.

[0040] The material tray adopts a segmented casting and integral assembly method, with casting dimensions of 1500mm*1500mm*150mm. The four sub-material trays are fixed by welding with screws. This design scheme has been verified by the use of the heat treatment furnace, and the strength and service life of the material trays meet the design requirements.

[0041] Furthermore, the support rib 22 is cylindrical in shape, and eight reinforcing concave edges 221 are evenly arranged on the edge, which are recessed inward. A connecting edge 222 is provided between two reinforcing concave edges 221, and two adjacent support ribs 22 are connected to each other by sharing a connecting edge 222; four adjacent support ribs 22 form a "four-pointed star" shape.

[0042] The structure of the support rib 22 is further improved in the cylindrical form. The design of the concave edge 221 not only strengthens the pressure resistance of the support rib 22, but also allows the support rib 22 to be arranged more closely in the frame 21, so that the support rib 22 and any position of the connection of the support rib 22 have good support characteristics when they are compressed.

[0043] Furthermore, the wall thickness of the frame 21 and the support rib 22 is consistent and uniform, ensuring that the wall thickness of each part cools at a uniform rate, which can effectively reduce stress, deformation and cracking, and prevent metal accumulation (heat spots) from causing shrinkage cavities.

[0044] Furthermore, the support rib 22 set close to the inner wall of the frame 21 is a complete half of the support rib 22, which ensures the compressive strength of the material tray edge.

[0045] Furthermore, on one side of the frame 21, at the quarter-thickness of each side, there are connecting ears 223 in the shape of "Ω". The connecting ears 223 are placed inside the half of the support rib 22 and connected to the frame 21. When the sub-material trays 2 are spliced ​​together, the opening positions of the two connecting ears 223 correspond and surround to form a reinforcing ear 224, which facilitates the connection between the material trays and also strengthens the strength of the connection between the material trays.

[0046] Furthermore, one side of the frame 21 is divided into three sections using the connecting ear 223 as the dividing unit, and each section is provided with at least two sets of two rows of sockets, which are evenly distributed.

[0047] Furthermore, the four corners of the frame 21 are rounded. The rounded corner design can prevent the formation of hot spots, improve stress distribution, avoid the formation of pinholes, and effectively reduce the generation of shrinkage cavities.

[0048] Furthermore, the sub-plate 2 is integrally molded and cast using a wax mold precision casting method, increasing the smoothness of the product surface. This adjustment effectively prevents external elements from seeping into the plate during use, especially some harmful elements during the quenching process.

[0049] Furthermore, the chemical composition of the material tray includes the following elements by weight percentage: carbon (C) 0.1-0.2%, chromium (Cr) 24-27%, nickel (Ni) 19-22%, tungsten (W) 2.5-3.5%, cobalt (Co) 1.0-2.0%, niobium (Nb) 0.5-1.0%, sulfur (S) < 0.035%, and phosphorus (P) < 0.035%.

[0050] A reasonable element ratio can effectively enhance the strength of the tray and effectively dissipate the thermal stress of the workpiece during the cold extraction process, ensuring that the tray will not deform or crack, affecting its performance.

[0051] Reasonable main element ratio: The main elements in the steel bath are chromium (Cr) and nickel (Ni). Cr increases the hardenability of steel and has a secondary hardening effect, improving the hardness and wear resistance of carbon steel without making it brittle, resulting in better comprehensive mechanical properties after quenching and tempering. Adjusting the Cr content provides high-temperature oxidation resistance and resistance to oxidative corrosion, while also increasing the steel's hot strength. It can also form chromium-containing carbides, thereby improving the wear resistance of the material surface. Nickel mainly strengthens ferrite and refines pearlite, increasing the strength of steel without significantly reducing its toughness. Increasing the Ni content by 1% can increase the strength by approximately 29.4 Pa, while the yield strength increases faster than the tensile strength, and its impact on the toughness, plasticity, and other processing properties is less than that of other alloying elements. Ni can improve the steel's resistance to fatigue and reduce its sensitivity to notches.

[0052] The addition of trace elements: The casting tray design incorporates rare metal elements tungsten (W), cobalt (Co), and niobium (Nb). A small amount of W dissolves in liquid iron and forms special carbides with carbon, promoting the transformation of austenite into martensite, enhancing hardness, wear resistance, and durability. Co promotes martensite transformation, increasing toughness and strength. Nb refines the grain size, increasing the tray's thermal strength and resistance to rapid cooling and thermal stress, while effectively preventing excessive carbon infiltration during heat treatment, thus avoiding product cracking.

[0053] In this embodiment, further strength simulation experiments were conducted on the structural and material properties of the material tray: the geometric model was simplified accordingly for simulation analysis, and the simplification is as follows:

[0054] 1) Simulation model

[0055] A 1 / 4 scale model was used for simulation to reduce the number of meshes and thus reduce workload.

[0056] 2) Boundary and load conditions

[0057] The simulation content is divided into load-bearing strength simulation and quenching simulation, and the boundary conditions are divided into two categories, which are described using this material tray as an example.

[0058] (1) Load simulation: Based on the actual load-bearing capacity of the material tray, its bottom is supported by 5 200mm*300mm sleepers, and the upper part is a uniformly distributed load. Its 1 / 4 load is 5000kg (converted to a uniformly distributed pressure load based on the contact area); X=0 and Z=0 planes are symmetrical planes;

[0059] (2) Quenching simulation: The vertical (y-direction) displacement of the bottom is constrained, and the X=0 and Z=0 planes are symmetrical planes; the initial temperature is 900℃, the quenching medium temperature is 25℃, and the heat transfer coefficient is 1000W / m2.℃.

[0060] Among them, such as Figure 4 and Figure 5 As shown, the boundary of the material tray remains symmetrical, and the support ribs 22 are still arranged vertically.

[0061] 3) Grid generation

[0062] like Figure 6 As shown, the material tray uses a hexahedral grid, the grid type is C3D8R, the grid size is 5mm, and this material tray has a capacity of 650,000.

[0063] 4) Material parameters

[0064] The material of the tray is stainless steel, and its material parameters are shown in the table below:

[0065] Material parameters

[0066] density thermal conductivity 7830kg / m3 40W / (m.℃) elastic modulus Specific heat capacity 208GPa 500J / (kg.℃) Poisson's ratio coefficient of expansion 0.28 1.15E-05 Yield limit tensile strength 600MPa 850MPa

[0067] The load-bearing strength simulation results are as follows:

[0068] The load-bearing capacity is 5t (1 / 4) of weight evenly supported on the top of the material tray, with the bottom supported by refractory bricks. The stress, deformation, and displacement results are as follows: Figure 7 , Figure 8 As shown.

[0069] The stress distribution at the top of the material tray is relatively uniform, while the maximum stress at the bottom is distributed at the outer edge where the material tray contacts the refractory brick ladle. The maximum stress is 7.32 MPa, which is far below the yield limit, indicating that the strength meets the requirements.

[0070] like Figure 9 As shown, the location where the material tray undergoes significant deformation and displacement is in the gap between the refractory bricks. The maximum displacement of the material tray is 0.004 mm, which is relatively small and meets the structural strength requirements.

[0071] The quenching simulation results are as follows:

[0072] The quenching conditions were: initial temperature 940℃, medium temperature 25℃, and quenching time 100s. Simulation calculations were performed on the deformation and stress distribution of the material tray, and the stress and deformation displacement distribution are as follows: Figure 10 As shown.

[0073] like Figure 11 As shown, the material tray structure generates large residual stress on the symmetrical boundary and at the four edges, with maximum stresses of 290.8 MPa and 235.6 MPa, respectively.

[0074] During the quenching process, the material tray undergoes deformation from the periphery to the center due to cooling and shrinkage. The maximum deformation occurs at the diagonal, which is 21.03 mm, while the minimum deformation occurs at the very center of the material tray.

[0075] The present invention has been described by the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A casting try for a chamber furnace, characterized in that: It consists of four identical square sub-discs joined together to form the square disc body; The sub-material tray includes a frame and supporting ribs. The supporting ribs are arranged vertically in the shape of hollow cylindrical columns. Several supporting ribs are closely connected to each other and arranged in a matrix within the frame. Two adjacent support ribs share a common side; The side of the frame is provided with a socket; The supporting rib is cylindrical in shape and includes a reinforcing concave edge. Adjacent supporting ribs are connected to each other by a common connecting edge. Four adjacent supporting ribs form a "four-pointed star" shape. On one side of the frame, at one-quarter of each side, "Ω"-shaped connecting ears are respectively provided. The connecting ears are placed inside one-half of the supporting rib and connected to the frame. When the sub-material trays are spliced ​​together, the opening positions of the two connecting ears correspond and form a reinforcing ear. The chemical composition of the material tray includes the following elements by weight percentage: carbon (C) 0.1-0.2%, chromium (Cr) 24-27%, nickel (Ni) 19-22%, tungsten (W) 2.5-3.5%, cobalt (Co) 1.0-2.0%, niobium (Nb) 0.5-1.0%, sulfur (S) < 0.035%, and phosphorus (P) < 0.035%.

2. A casting try for a chamber furnace as claimed in claim 1, characterized in that: The frame and supporting ribs have the same and uniform wall thickness.

3. A casting try for a chamber furnace as claimed in claim 1, characterized in that: The supporting rib, which is located close to the inner wall of the frame, is one half of the completed supporting rib.

4. A casting try for a chamber furnace as claimed in claim 1, characterized in that: One side of the frame is divided into three sections by the connecting ears. Each section has at least two sets of two rows of sockets, which are evenly distributed.

5. A casting try for a chamber furnace as claimed in claim 1, characterized in that: The four corners of the frame are rounded.

6. A casting try for a chamber furnace as claimed in claim 1, characterized in that: The sub-material tray is integrally formed and cast using a wax mold precision casting method.

7. A casting try for a hearth as claimed in claim 1, characterized in that: The sub-material trays are fixed together by screw welding.

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