A stainless steel / carbon steel clad pipe pouring system and production system

Abstract

The application discloses a stainless steel / carbon steel composite pipe pouring system and a production system, which comprises a pouring system, a pretreatment mechanism for treating a base pipe before pouring, a heating furnace, a heating system and a heat treatment mechanism for heat treating the composite pipe after pouring; the heating system and an atmosphere protection system are respectively connected with the heating furnace through pipelines; the system has reliable structure, high automation degree, does not need a large number of manual operations, improves product stability and production efficiency; the system adopts a solid-liquid composite structure to produce the stainless steel / carbon steel composite pipe, reduces the requirement for vacuum degree in the production process, realizes metallurgical combination through fusion between the stainless steel / carbon steel interfaces, and the strength is sufficient to meet the demand of subsequent hot rolling production; and the system is designed with inner and outer double-layer ceramic molds, simplifies the complex pre-process flow when solid-liquid composite is carried out by adopting sand casting or lost foam casting, and can adapt to production requirements of various specifications and various components.

Description

Technical Field

[0001] This invention relates to the field of bimetallic composite material preparation, specifically to a stainless steel / carbon steel composite pipe casting system and production system. Background Technology

[0002] Bimetallic composite materials are novel materials prepared by combining two metals with different properties through various composite technologies. They not only give full play to the corrosion resistance, heat resistance, and wear resistance of the composite material, but also combine the strength and stiffness of the base material, giving them comprehensive properties that cannot be achieved by a single component metal. This makes them more suitable for the increasingly high requirements of materials in the rapid development of industry and technology.

[0003] Stainless steel composite pipes are made by bonding a layer of highly corrosion-resistant stainless steel to carbon steel or low-alloy steel pipes using a specific process. This allows them to adapt to highly corrosive environments while significantly reducing the amount of expensive stainless steel used, thus substantially lowering production costs. Currently, bimetallic composite pipe forming technologies mainly include mechanical forming and metallurgical forming methods. Mechanical forming methods primarily include mechanical diameter expansion, explosive diameter expansion, and sizing methods, while metallurgical forming methods mainly include hot rolling, hot extrusion, and centrifugal casting.

[0004] In summary, there is currently no efficient production system for producing large-diameter carbon steel / stainless steel composite pipes using a solid-liquid composite method. Therefore, developing a novel carbon steel / stainless steel solid-liquid composite casting equipment and production system is crucial to addressing the issues of temperature control, surface quality, and production efficiency during the solid-liquid composite casting process. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a stainless steel / carbon steel composite pipe casting system and production system.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a stainless steel / carbon steel composite pipe casting system, including a casting zone, a base pipe, a rotating component for driving the base pipe to rotate, a ceramic mold, a steel holding tank, and a lifting mechanism;

[0007] The base tube is vertically installed in the casting area via a rotating assembly. The ceramic mold is located inside the base tube and has casting cavities between itself and the inner wall and bottom wall of the base tube. The steel container is located inside the base tube and has a steel pouring channel between itself and the top of the ceramic mold. The steel pouring channel is connected to the casting cavity. The lower end of the lifting mechanism is connected to the steel container and the ceramic mold, respectively. The lifting mechanism drives the steel container and the ceramic mold to move vertically up and down along the base tube.

[0008] Furthermore, in a preferred embodiment of the present invention, the lifting mechanism includes a driving component and a lifting positioning shaft connected to the driving component, and the lower end of the lifting positioning shaft is connected to the steel drum and the ceramic mold respectively.

[0009] Furthermore, in a preferred embodiment of the present invention, the ceramic mold includes an inlet section, an outlet section located below the inlet section, and a transition section connecting the inlet section and the outlet section;

[0010] The diameter of the inlet section is smaller than the diameter of the outlet section, so that the ceramic mold has a tapered structure as a whole, and the taper is 0.5% / m-3% / m.

[0011] Furthermore, in a preferred embodiment of the present invention, the steel drum is provided with a temperature control device and a flow control device.

[0012] Furthermore, in a preferred embodiment of the present invention, a cooling system is provided at the bottom end of the base tube and at a position corresponding to the ceramic mold, and the composite layer leaving the ceramic mold is cooled by the cooling system.

[0013] Furthermore, in a preferred embodiment of the present invention, an atmosphere protection system is provided below the casting area.

[0014] The present invention also provides a stainless steel / carbon steel composite pipe production system, including the above-mentioned casting system, a pretreatment mechanism for treating the base pipe before casting, a heating furnace, a heating system, and a heat treatment mechanism for heat treatment of the cast composite pipe; the heating system and the atmosphere protection system are respectively connected to the heating furnace through pipelines.

[0015] Furthermore, in a preferred embodiment of the present invention, the pretreatment mechanism includes a finishing component for finishing the base tube and a scrap steel recycling bin located below the base tube.

[0016] Furthermore, in a preferred embodiment of the present invention, the heat treatment mechanism includes a heat treatment tank for quenching the cast composite tube and a tempering treatment section for medium-temperature tempering the quenched composite tube.

[0017] Furthermore, in a preferred embodiment of the present invention, the base pipe before casting is moved to the casting area by a lifting device, and the composite pipe after casting is moved to the heat treatment tank and the tempering treatment section.

[0018] The present invention has the following beneficial effects: The stainless steel / carbon steel composite pipe casting system and production system provided by the present invention have a reliable structure, a high degree of automation, require no large amount of manual operation, have a smooth production process, and improve product stability and production efficiency; the system adopts a solid-liquid composite structure to produce stainless steel / carbon steel composite pipes, reducing the vacuum requirements of the production process, and the stainless steel / carbon steel interface achieves metallurgical bonding through fusion, with sufficient strength to meet the needs of subsequent hot rolling production; moreover, the system simplifies the complex pre-process of solid-liquid composite using sand casting or lost foam casting by designing inner and outer double-layer ceramic molds, and can adapt to the production requirements of various specifications and compositions; at the same time, the ceramic mold clamping can be reused, which facilitates the transportation of ceramic molds and prevents the stainless steel ceramic mold from bulging and deforming, thus improving the surface quality of the composite layer. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the gating system in this invention;

[0020] Figure 2 This is a schematic diagram of the ceramic mold structure in this invention;

[0021] Figure 3 This is a schematic diagram of the production system structure in this invention;

[0022] In the diagram: 1-Pouring area, 2-Base layer pipe, 3-Rotating component, 4-Ceramic mold, 5-Steel container, 6-Lifting mechanism, 7-Pouring cavity, 8-Pouring channel, 9-Drive component, 10-Lifting and positioning shaft, 40-Inlet section, 41-Outlet section, 42-Transition section, 12-Cooling system, 13-Atmosphere protection system, 14-Pretreatment mechanism, 15-Heating furnace, 16-Heating system, 17-Heat treatment mechanism, 140-Scrap steel recycling bin. Detailed Implementation

[0023] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] like Figure 1 As shown, a stainless steel / carbon steel composite pipe casting system includes a casting zone 1, a base pipe 2, a rotating assembly 3 for driving the base pipe 2 to rotate, a ceramic mold 4, a steel holding tank 5, and a lifting mechanism 6.

[0025] The carbon steel / stainless steel composite pipe has a diameter of 100-6000mm and a height of 500-6000mm. The outer wall is a base pipe 2 with a thickness of 100-300mm, and the inner wall is a composite layer with a thickness of 10-30mm. The base pipe 2 can be made of stainless steel or carbon steel. A steel container 5 can hold molten stainless steel or molten carbon steel as the composite layer on the inner wall of the base pipe 2, and the material of this composite layer is different from that of the base pipe 2.

[0026] The base tube 2 is vertically set in the casting area 1 by the rotating component 3. The ceramic mold 4 is located inside the base tube 2 and has casting cavities 7 between it and the inner wall and bottom wall of the base tube 2 respectively. The steel bucket 5 is located inside the base tube 2 and has a steel pouring channel 8 between it and the top of the ceramic mold 4. The steel pouring channel 8 is connected to the casting cavity 7. The lower end of the lifting mechanism 6 is connected to the steel bucket 5 and the ceramic mold 4 respectively. The lifting mechanism 6 drives the steel bucket 5 and the ceramic mold 4 to rise and fall vertically along the base tube 2.

[0027] The high-temperature ceramic mold 4 is made of alumina. The preheated base tube 2 is hoisted to the pouring area 1 and positioned by the rotating component 3. The ceramic mold 4 is lowered to the bottom of the base tube 2 by the top lifting mechanism 6. Before pouring, the ceramic mold 4 is preheated to 1400℃. The ceramic mold 4 and the base tube 2 are aligned by the positioning shaft of the lifting mechanism 6. The distance between the two is the pouring cavity 7. Preferably, the distance is 15mm, which is the thickness of the composite layer to be poured. A steel-holding drum 5 is installed on top of the high-ceramic mold to hold the molten steel for the composite layer and control the superheat of the pouring at 50-70°C above the liquidus line. During the pouring process, the outlet of the steel-holding drum 5 is opened, and the molten steel flows from the outlet into the pouring channel 8 and then into the pouring cavity 7. The pouring speed is controlled by the flow control device inside the steel-holding drum 5. At the same time, the top lifting mechanism 6 drives the ceramic mold 4 to rise at a speed of 1.2 mm / s, and the base tube 2 rotates at a speed of 15 rpm driven by the rotating component 3 during this process. The bottom of the ceramic mold 4 is equipped with a cooling system 12, which cools the inner wall of the stainless steel composite layer that has just left the contact surface of the ceramic mold 4 with high-pressure argon gas at a speed of not less than 20°C / s during the mold lifting process. This ensures that the pouring zone 1 maintains an inert or reducing atmosphere throughout the pouring process, guaranteeing the pouring effect. This invention improves the surface quality of the composite layer compared to centrifugal casting by simultaneously moving the ceramic mold during the casting process and cooling the blank shell beneath it. The pressure from the ceramic mold significantly enhances the surface quality compared to centrifugal casting, resulting in a smooth inner wall and preventing irregular shapes. Furthermore, the pressure from the ceramic mold improves the internal quality of the composite layer, mitigating shrinkage cavities and segregation. It also strengthens the bond between the composite layer and the base layer. The mold movement process is also a demolding process; as the casting liquid reaches the top of the base tube, the ceramic mold moves to the top and is then removed from the base tube. The entire process is smooth and fast, greatly improving production efficiency.

[0028] To improve the performance of the lifting mechanism 6, the lifting mechanism 6 in this invention includes a driving component 9 and a lifting positioning shaft 10 connected to the driving component 9. The lower end of the lifting positioning shaft 10 is connected to the steel drum 5 and the ceramic mold 4, respectively. The driving action of the driving component 9 drives the lifting positioning shaft 10 to rise and fall, thereby driving the steel drum 5 and the ceramic mold 4 to rise and fall at a certain speed. The lifting is reliable and stable, improving the uniformity of molten steel flowing into the casting cavity 7 during the rising process.

[0029] To improve the quality of the interior and surface of the composite layer, such as Figure 2As shown, in this invention, the ceramic mold 4 includes an inlet section 40, an outlet section 41 located below the inlet section 40, and a transition section 42 connecting the inlet section 40 and the outlet section 41. The diameter of the inlet section 40 is smaller than the diameter of the outlet section 41. The transition section 42 has a tapered structure with a taper of 0.5% / m to 3% / m. The transition section 42 is 150mm long and can exert a squeezing effect on the incompletely solidified composite layer during the casting process, thereby improving the internal and surface quality of the composite layer.

[0030] like Figure 3 As shown, the present invention also provides a stainless steel / carbon steel composite pipe production system, including a casting system, a pretreatment mechanism 14 for treating the base pipe 2 before casting, a heating furnace 15, a heating system 16, and a heat treatment mechanism 17 for heat treatment of the cast composite pipe; the heating system 16 and the atmosphere protection system 13 are respectively connected to the heating furnace 15 through pipelines.

[0031] The inner wall of the base tube 2 is finished by the pretreatment mechanism 14, thereby further processing to improve the roughness and increase the bonding area and bonding strength of the carbon steel / stainless steel joint. The base tube 2 is preheated by the heating furnace 15. First, the base tube 2 is preheated by the internal ambient temperature of the heating furnace 15. Before casting, the inner wall of the base tube 2 is heated by the heating system 16 until the base tube 2 reaches the predetermined heating temperature of 100-1800℃. The preheating time is 0.1-10 hours. The heating furnace 15 maintains an inert atmosphere or a reducing atmosphere throughout the preheating process. As mentioned above, the solid-liquid composite of the base tube 2 and the composite steel liquid is achieved by the casting system. The composite tube structure is reliable and of good quality after composite. The composite tube is lifted to the heat treatment mechanism 17 by a hoist. The cooling and heat treatment operation process is formulated according to the production requirements. The cooling method includes one or more of furnace cooling, air cooling, pile cooling, water quenching, and oil quenching. The heat treatment process includes one or more of annealing, normalizing, tempering, and quenching. After passing the flaw detection inspection, the product is finished and packaged.

[0032] The pretreatment unit 14 includes a finishing component for finishing the base tube 2 and a scrap steel recycling bin 140 located below the base tube 2. During the finishing process, the inner wall of the base tube 2 is threaded, ground, or corroded by the finishing component to improve its roughness. The finished steel shavings fall into the scrap steel recycling bin 140 for recycling, avoiding pollution of the processing environment. The recycled steel shavings can be used for other processing, realizing recycling and reuse.

[0033] The base pipe 2, before casting, is lifted into the casting area using a hoist, and the composite pipe, after casting, is lifted into the heat treatment tank and tempering treatment section. Throughout the production process, the base pipe 2 and the composite pipe after casting are kept upright and transported via top hoisting equipment and guide rails in the heating furnace 15.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A stainless steel / carbon steel composite pipe casting system, characterized in that, It includes a pouring area (1), a base pipe (2), a rotating assembly (3) for driving the base pipe (2) to rotate, a ceramic mold (4), a steel container (5), and a lifting mechanism (6); The base tube (2) is vertically set in the casting area (1) by a rotating component (3). The ceramic mold (4) is located inside the base tube (2) and has casting cavities (7) between it and the inner wall and bottom wall of the base tube (2). The steel bucket (5) is located inside the base tube (2) and has a steel pouring channel (8) between it and the top of the ceramic mold (4). The steel pouring channel (8) is connected to the casting cavity (7). The lower end of the lifting mechanism (6) is connected to the steel bucket (5) and the ceramic mold (4) respectively. The lifting mechanism (6) drives the steel bucket (5) and the ceramic mold (4) to move vertically up and down along the base tube (2). The lifting mechanism (6) includes a driving component (9) and a lifting positioning shaft (10) connected to the driving component (9), and the lower end of the lifting positioning shaft (10) is connected to the steel drum (5) and the ceramic mold (4) respectively. The ceramic mold (4) includes an inlet section (40), an outlet section (41) located below the inlet section (40), and a transition section (42) connecting the inlet section (40) and the outlet section (41). The diameter of the inlet section (40) is smaller than the diameter of the outlet section (41), and the transition section has a tapered structure with a taper of 0.5% / m-3% / m.

2. The stainless steel / carbon steel composite pipe casting system according to claim 1, characterized in that, The steel drum (5) is equipped with a temperature control device and a flow control device.

3. The stainless steel / carbon steel composite pipe casting system according to claim 2, characterized in that, A cooling system (12) is provided at the bottom end of the base tube (2) and at a position corresponding to the ceramic mold (4), and the composite layer leaving the ceramic mold (4) is cooled by the cooling system (12).

4. The stainless steel / carbon steel composite pipe casting system according to any one of claims 1 to 3, characterized in that, An atmosphere protection system (13) is provided below the pouring area (1).

5. A stainless steel / carbon steel composite pipe production system, characterized in that, The system includes the casting system as described in claim 4, and further includes a pretreatment mechanism (14) for treating the base pipe (2) before casting, a heating furnace (15), a heating system (16), and a heat treatment mechanism (17) for heat treatment of the composite pipe after casting; the heating system (16) and the atmosphere protection system (13) are respectively connected to the heating furnace (15) through pipelines.

6. The stainless steel / carbon steel composite pipe production system according to claim 5, characterized in that, The pretreatment unit (14) includes a finishing component for finishing the base tube (2) and a scrap steel recycling bin (140) located below the base tube (2).

7. A stainless steel / carbon steel composite pipe production system according to claim 5, characterized in that, The heat treatment mechanism (17) includes a heat treatment tank for quenching the cast composite pipe and a tempering treatment section for tempering the quenched composite pipe at medium temperature.

8. The stainless steel / carbon steel composite pipe production system according to claim 7, characterized in that, The base pipe (2) before casting is moved to the casting area by a hoist, and the composite pipe after casting is moved to the heat treatment pool and the tempering treatment section.

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