Preparation method of NS3103 thousand-degree-grade heat-resistant element

Abstract

The invention relates to a preparation method of an NS3103 thousand-degree-grade heat-resistant element, and belongs to the field of material forming and processing. The preparation of the heat-resistant element is completed by using a ceramic auxiliary basic part to perform investment casting molding, heating the basic part, inserting the basic part into a plate in a heating state, and performing integral slow cooling molding. The preparation method specifically comprises the following steps: step 1, molding; 2, making a shell; step 3, roasting; step 4, smelting and pouring; and 5, cleaning and hot press molding are conducted. By improving the dimensional precision of the basic part and combining the hot press molding process, the problem that a large gap exists after a plate is inserted into the basic part is solved, and after batch production, the NS3103 thousand-degree-grade heat-resistant element matching part is compact and stable in production quality.

Description

Technical Field

[0001] This invention belongs to the field of material forming and processing, and specifically relates to a method for preparing an NS3103 thousand-degree heat-resistant element. Background Technology

[0002] The overall structure of the NS3103 1000°C heat-resistant element is shown in the attached figure. Figure 1 As shown, the outline dimension is 146mm. 146mm 204mm, outer frame wall thickness 8.5mm, internal partition thickness 6mm, gap width between partitions 3mm. The casting material is 1Cr23Ni60Fe13Al (numerical code: NS3103), and the oxidation resistance requirement is that the weight gain should not exceed 0.1g / cm2•h after 100 hours at 1100℃.

[0003] For the manufacture of heat-resistant components, a cast base component is used, which is then welded together with a plate. The structure of the base component and the plate is shown in the attached figure. Figure 2 , 3 As shown, the basic component's outline dimension is 146mm. 146mm 204mm, outer frame wall thickness 8.5mm, internal partition thickness 6mm, 7 through gaps in total, 6 of which are 12mm wide and 1 is 21mm wide; panel size is 128mm. 6mm 204mm. The basic components and plates are prepared using silica sol investment casting. To ensure that the blanks can be assembled, the tolerances are ±(1-1.5)mm. The mating surfaces of the assembled components have gaps of 0.5-1mm or cannot be installed, resulting in poor overall integrity after assembly. The weld pool depth at the ends of the basic components and plates is 3-4mm. During the subsequent end face machining, due to the datum positioning deviation, the weld points are removed, resulting in a defect of weak welded plates.

[0004] The NS3103 heat-resistant element is manufactured by inserting a 6mm plate into the base component and welding the ends. The plate and the base component are only welded at both ends, and there is a gap of 0.5-1mm between the plate and the base component, resulting in poor overall integrity. In addition, the weld pool depth is 4-6mm. During the subsequent end face processing, due to the datum positioning deviation, the weld points are processed and removed, resulting in a defect of weak welded plate. Summary of the Invention

[0005] (a) Technical problems to be solved The technical problem to be solved by the present invention is to provide a method for preparing NS3103 thousand-degree heat-resistant elements to solve the problems of large dimensional deviations in the investment casting of the basic components and poor bonding between the basic components and the insert plate in the later stage.

[0006] (II) Technical Solution To solve the above-mentioned technical problems, the present invention provides a method for preparing NS3103 thousand-degree heat-resistant element. The method involves using a ceramic auxiliary base component for investment casting, heating the base component, inserting the base component into a plate while it is heated, and then slowly cooling the entire component to complete the preparation of the heat-resistant element. The preparation method specifically includes: Step 1: Mold making; Step 2: Shell making; Step 3: Firing; Step 4: Melting and casting; Step 5: Cleaning and hot pressing.

[0007] Step 1 specifically includes: Step 11: Tree grouping process design; The basic component assembly process adopts the top-pour process, with a T-shaped gating system consisting of a gating system and feeding risers. The heat is dispersed through two feeding risers. The castings are placed in the side-standing direction of the plate, and conformal ceramics are placed in the gaps between the castings. The plate assembly process adopts the top-hold process, with four pieces in a group. The gating system consists of a T-shaped gating system, a horizontal gating system, and an ingate.

[0008] Step 12: Create the model group tree; Before pressing the basic casting, the ceramic core is placed in the investment molding mold and molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. The plate is directly molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. After the pressed wax mold is left to stand for 4 to 6 hours, it is welded according to the assembly process.

[0009] Step 2 specifically involves using a full silica sol shell manufacturing process. The shell consists of 7 layers: the first layer is the surface layer, the second layer is the transition layer, and the third to seventh layers are the reinforcing layers. Each layer of the shell needs to be fully dried before proceeding with the subsequent layers. Dewaxing was carried out using a steam dewaxing process with a steam pressure of 0.40–0.55 MPa and a dewaxing time of 20–30 minutes.

[0010] Step 3 specifically involves: firing the shell at a high temperature of 1050-1150℃ for 3-5 hours, and then directly casting the shell after firing.

[0011] Step 4 specifically includes: Step 41: Melting is carried out using a 500kg medium-frequency induction melting furnace; Step 42: Control the temperature of the molten steel after melting and the pouring temperature, and begin pouring.

[0012] In step 41, the furnace lining uses neutral furnace material, and the metal materials used in the furnace are pure iron, metallic manganese, micro-carbon ferrochrome, electrolytic nickel, and aluminum balls. They are added in the following order: pure iron, electrolytic nickel, and part of micro-carbon ferrochrome. After cleaning, micro-carbon ferrochrome, metallic manganese, and aluminum balls are added in sequence.

[0013] Step 5 specifically includes: Step 51: Cleaning; After pouring, allow the material to cool naturally to room temperature before removing it from the shell, and then clean it with high-pressure water at a pressure of not less than 6.0 MPa. Step 52: Heating the casting; Heat the basic component to a certain temperature and hold it for 20-30 minutes, then remove it for plate insertion. Step 53: Insert plate forming; While the base component is hot, the plate is inserted into the groove of the base component, and a press is used to press the plate completely into the base component, thus completing the preparation of the internal heating element.

[0014] (III) Beneficial Effects Compared with existing technologies, this invention has the following advantages: by improving the dimensional accuracy of the basic component and combining it with a hot-pressing process, the problem of large gaps after the plate is inserted into the basic component is solved. Furthermore, after batch production, the NS3103 thousand-degree heat-resistant component has tightly fitted parts, resulting in stable production quality. This provides a solution for producing high-temperature resistant components with narrow gaps. Attached Figure Description

[0015] Figure 1 This is a structural diagram of the NS3103 thousand-degree heat-resistant element; Figure 2 This is a process diagram for assembling basic components; Figure 3 This is a diagram of the board assembly process. Figure 4 This is a schematic diagram of the basic components and the assembly of the plate. Detailed Implementation

[0016] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0017] Example 1 This embodiment provides a method for preparing NS3103 thousand-degree heat-resistant element. The method involves using a ceramic auxiliary base component for investment casting, heating the base component, inserting the base component into a plate while it is heated, and then slowly cooling the entire component to complete the heat-resistant element preparation. The preparation method specifically includes: Step 1: Mold making; Step 2: Shell making; Step 3: Firing; Step 4: Melting and casting; Step 5: Cleaning and hot pressing.

[0018] Step 1 specifically includes: Step 11: Tree grouping process design; The basic component assembly process adopts the top-pour process, with a T-shaped gating system consisting of a gating system and feeding risers. The heat is dispersed through two feeding risers. The castings are placed in the side-standing direction of the plate, and conformal ceramics are placed in the gaps between the castings. The plate assembly process adopts the top-hold process, with four pieces in a group. The gating system consists of a T-shaped gating system, a horizontal gating system, and an ingate.

[0019] Step 12: Create the model group tree; Before pressing the basic casting, the ceramic core is placed in the investment molding mold and molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. The plate is directly molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. After the pressed wax mold is left to stand for 4 to 6 hours, it is welded according to the assembly process.

[0020] Step 2 specifically involves using a full silica sol shell manufacturing process. The shell consists of 7 layers: the first layer is the surface layer, the second layer is the transition layer, and the third to seventh layers are the reinforcing layers. Each layer of the shell needs to be fully dried before proceeding with the subsequent layers. Dewaxing was carried out using a steam dewaxing process with a steam pressure of 0.40–0.55 MPa and a dewaxing time of 20–30 minutes.

[0021] Step 3 specifically involves: firing the shell at a high temperature of 1050-1150℃ for 3-5 hours, and then directly casting the shell after firing.

[0022] Step 4 specifically includes: Step 41: Melting is carried out using a 500kg medium-frequency induction melting furnace; Step 42: Control the temperature of the molten steel after melting and the pouring temperature, and begin pouring.

[0023] In step 41, the furnace lining uses neutral furnace material, and the metal materials used in the furnace are pure iron, metallic manganese, micro-carbon ferrochrome, electrolytic nickel, and aluminum balls. They are added in the following order: pure iron, electrolytic nickel, and part of micro-carbon ferrochrome. After cleaning, micro-carbon ferrochrome, metallic manganese, and aluminum balls are added in sequence.

[0024] Step 5 specifically includes: Step 51: Cleaning; After pouring, allow the material to cool naturally to room temperature before removing it from the shell, and then clean it with high-pressure water at a pressure of not less than 6.0 MPa. Step 52: Heating the casting; Heat the basic component to a certain temperature and hold it for 20-30 minutes, then remove it for plate insertion. Step 53: Insert plate forming; While the base component is hot, the plate is inserted into the groove of the base component, and a press is used to press the plate completely into the base component, thus completing the preparation of the internal heating element.

[0025] Example 2 This embodiment provides a method for preparing an NS3103 thousand-degree-class heat-resistant element, specifically including: 1: Design of the dimensions of the mating surfaces between basic components and plates The mating surfaces of the basic component and the plate are φ6.5mm circular arc grooves and circular arc surfaces. The distance between the top of the circular arc groove of the basic component and the inner cavity plane is 2mm. The mating surfaces of the basic component are formed using ceramic core investment casting, with dimensional tolerances designed between 0 and 0.1mm. The plate is formed using silica sol investment casting, with dimensional tolerances designed between -0.18mm and 0.

[0026] 2: Mold making 2.1: Basic Component Assembly Process Design The casting process is designed as a top-casting process. Two 146mm×80mm×52mm feeding risers are placed on top of the base component with the ceramic core. The distance between the feeding risers is 52mm, and the distance between the side face of the feeding riser and the side face of the base component is 25mm. T-shaped sprues are placed on the feeding risers. The assembly process for the base component is attached. Figure 2 As shown.

[0027] 2.2: Panel Assembly Tree Process Design The casting process is designed as a top-pour process. The horizontal runner is 100mm in size. 30mm 25mm; two 20mm ingates are placed on the side of the plate. 15mm 10mm, connect the ingate to one side of the horizontal runner, and connect the opposite side of the horizontal runner to the T-shaped runner, 4 pieces per group. The board assembly process is attached. Figure 3 As shown.

[0028] 2.3: Modeling Tree The mold is made using a low-temperature molding compound with a paraffin-stearic acid weight ratio of 1:1. The wax injection pressure is controlled at 0.15-0.35 MPa. Before wax injection of the basic component, six 12mm thick ceramic cores and one 21mm thick ceramic core are placed in the investment mold. The wax mold of the basic component is naturally pressed for 20-35 minutes and then removed from the mold. The plates, shrinkage risers, ingates, T-sprues, and runners are naturally pressed for 5-10 minutes and then removed from the mold. After the pressed wax molds are left to stand for 4-6 hours, they are welded together according to the tree assembly process.

[0029] 3: Shell making The shell is manufactured using a full silica sol molding process, and consists of 7 layers. The coating and sand application details for each layer are shown in the table. Number of shell layers Sand particle size / mesh Coating viscosity / S air drying time / h surface layer 120 25～35 6～8 transition layer 40～70 20～30 6～8 Floors 3 to 7 16～40 15～25 10～12 Steam dewaxing is used, with a steam pressure of 0.40–0.55 MPa, a pressurization time of 15–25 s, a dewaxing temperature of 100–120 ℃, and a dewaxing time of 20–30 min.

[0030] 4: Roasting The shell is fired at a high temperature of 1050-1150℃ for 3-5 hours, and then cast directly at a high temperature.

[0031] 5: Smelting and casting A 500kg medium-frequency induction melting furnace was used for smelting, with a neutral furnace lining. The metal materials used were pure iron, metallic manganese, micro-carbon ferrochrome, electrolytic nickel, and aluminum balls. The charging sequence was as follows: 300kg of electrolytic nickel, 17.5kg of pure iron, and 125kg of micro-carbon ferrochrome were added with the furnace. After melting and clearing, 55kg of micro-carbon ferrochrome, 8kg of metallic manganese, and 7.5kg of aluminum balls were added sequentially. The materials must be free of oil, rust, and water before being added to the furnace.

[0032] The tapping temperature of the molten 1Cr23Ni60Fe13Al steel after smelting is controlled at 1580~1610℃, and the casting temperature is controlled at 1520~1550℃. The molten steel is cooled for 3 minutes before casting.

[0033] 6: Cleaning After pouring, allow the water to cool naturally to room temperature for rough cleaning, followed by fine cleaning with high-pressure water at a pressure of no less than 6.0 MPa.

[0034] 7: Heating of basic components Heat the basic component to 350-400℃ at a heating rate of ≤80℃ / h, and remove it after 20-30 minutes of uniform heating for insertion.

[0035] 8: Hot pressing Insert the eight plates into the grooves of the basic component in sequence. See the attached diagram for an assembly diagram. Figure 4 The board insertion process is completed within 45 seconds. A press is used to completely press the board into the base component. The assembled components are covered with heat insulation cotton and slowly cooled to room temperature. Spot welding is used at the interface to further fix the board and the base component, thus completing the preparation.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an NS3103 thousand-degree-class heat-resistant element, characterized in that, The heat-resistant element is prepared by using ceramic auxiliary basic parts for investment casting, heating the basic parts, inserting the basic parts into the plate while they are heated, and then slowly cooling the whole piece to form the final product. The preparation method specifically includes: Step 1: Mold making; Step 2: Shell making; Step 3: Firing; Step 4: Melting and casting; Step 5: Cleaning and hot pressing.

2. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 1, characterized in that, Step 1 specifically includes: Step 11: Tree grouping process design; The basic component assembly process adopts the top-pour process, with a T-shaped gating system consisting of a gating system composed of a T-shaped gating system and a feeding riser. The heat is dispersed through two feeding risers. The castings are placed in the side-standing direction of the plate, and conformal ceramics are placed in the gaps between the castings. The plate assembly process adopts the top-hold process, with four pieces in a group. The gating system consists of a T-shaped gating system, a horizontal gating system, and an ingate. Step 12: Create the model group tree; Before pressing the basic casting, the ceramic core is placed in the investment molding mold and molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. The plate is directly molded using a low-temperature molding material with 50% paraffin wax and 50% stearic acid. After the pressed wax mold is left to stand for 4 to 6 hours, it is welded according to the assembly process.

3. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 2, characterized in that, Step 2 specifically involves using a full silica sol shell manufacturing process. The shell consists of 7 layers: the first layer is the surface layer, the second layer is the transition layer, and the third to seventh layers are the reinforcing layers. Each layer of the shell needs to be fully dried before proceeding with the subsequent layers. Dewaxing was carried out using a steam dewaxing process with a steam pressure of 0.40–0.55 MPa and a dewaxing time of 20–30 minutes.

4. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 3, characterized in that, Step 3 specifically involves: firing the shell at a high temperature of 1050-1150℃ for 3-5 hours, and then directly casting the shell after firing.

5. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 4, characterized in that, Step 4 specifically includes: Step 41: Melting is carried out using a 500kg medium-frequency induction melting furnace; Step 42: Control the temperature of the molten steel after melting and the pouring temperature, and begin pouring.

6. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 5, characterized in that, In step 41, the furnace lining uses neutral furnace material, and the metal materials used in the furnace are pure iron, metallic manganese, micro-carbon ferrochrome, electrolytic nickel, and aluminum balls. They are added in the following order: pure iron, electrolytic nickel, and part of micro-carbon ferrochrome. After cleaning, micro-carbon ferrochrome, metallic manganese, and aluminum balls are added in sequence.

7. The method for preparing the NS3103 thousand-degree-class heat-resistant element as described in claim 6, characterized in that, Step 5 specifically includes: Step 51: Cleaning; After pouring, allow the material to cool naturally to room temperature before removing it from the shell, and then clean it with high-pressure water at a pressure of not less than 6.0 MPa. Step 52: Heating the casting; Heat the basic component to a certain temperature and hold it for 20-30 minutes, then remove it for plate insertion. Step 53: Insert plate forming; While the base component is hot, the plate is inserted into the groove of the base component, and a press is used to press the plate completely into the base component, thus completing the preparation of the internal heating element.

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