Production method for improving yield of nickel steel composite plate

Abstract

The invention belongs to the field of composite plate processing, and particularly relates to a production method for improving the yield of nickel steel composite plates, which comprises the steps of billet cogging, nickel base alloy plate prefabrication, composite plate assembly, composite plate blank rolling, composite plate blank splitting and the like. Cogging is conducted on a steel billet under multi-pass large pressure, high-pressure water is used for spraying and cooling, and coarsening of crystal grains of a composite layer of a product is restrained; the nickel-based alloy plate is prepared by adopting rolling deformation instead of machining cutting, so that the production cost is reduced, and the production efficiency is improved; all procedures are closely linked, the thickness distribution of a product composite layer from the edge part to the core part is uniform, the problem that the thickness of the rolled product composite layer is not uniform is greatly weakened, and the yield and the finished product rate of the composite plate are remarkably improved; meanwhile, the composite board with excellent comprehensive performance can be obtained through controlled rolling and controlled cooling, the heat treatment procedure is omitted, energy conservation and emission reduction of enterprises are facilitated, industrial continuous efficient production is easier, practicability is high, and the composite board is worthy of application and popularization.

Description

Technical Field

[0001] The invention belongs to the field of composite plate processing, and in particular relates to a production method for improving the yield of nickel-steel composite plates. Background Art

[0002] Nickel-based alloys have excellent comprehensive properties such as high strength and resistance to oxidation and corrosion, and are widely used in aerospace, marine, chemical and rail transportation fields. However, the high content of elements such as chromium and molybdenum in nickel-based alloys significantly increases the production cost, limiting its application in the above-mentioned fields. Nickel-steel composite plates are prepared using metal composite material technology. The steel layer gives the plate good strength and rigidity, and the nickel layer provides excellent ductility and corrosion resistance, so that the nickel-steel composite plate meets the requirements of high strength, high toughness, high corrosion and low cost, while saving the use of nickel-based alloys, with good economic and social benefits. The vacuum rolling method combines the hot rolling method with the vacuum electron beam welding technology. The interface of the composite plate is in a high vacuum state, the interface is not oxidized during the heating process, and the interface bonding performance is high. It is one of the main methods for producing composite metal plates. However, due to the different deformation resistance of nickel-based alloys and steel, the thickness of the product composite layer from the core to the edge will be uneven during the rolling composite process, resulting in a thicker nickel-based alloy layer at the edge, which cannot meet the size requirements of the product composite layer. A large amount of trimming and scrapping is required, and the yield and finished product rate of nickel-steel composite plates are low. In addition, the grain size of the steel layer at the interface of the nickel-steel composite plate prepared by conventional methods is coarse, significantly larger than the grain size of the steel plate core, which reduces the bonding force and shear strength of the composite layer and shortens the service life of the nickel-steel composite plate. Summary of the invention

[0003] The invention provides a production method for improving the yield rate of nickel-steel composite plates, comprising the steps of steel billet opening, nickel-based alloy plate pre-preparation, composite plate assembly, composite plate billet rolling and composite plate billet separation; the steel billet is opened by adopting multiple large-pass pressing, and high-pressure water spraying is used for cooling to inhibit the coarsening of grains of the product composite layer; the nickel-based alloy plate is prepared by rolling deformation instead of machining, thereby reducing production costs and improving production efficiency; each process is closely connected, and the thickness of the product composite layer is evenly distributed from the edge to the core, which greatly reduces the problem of uneven thickness of the product composite layer after rolling, and significantly improves the yield rate and yield rate of the composite plate; at the same time, the composite plate with excellent comprehensive performance can be obtained by controlled rolling and controlled cooling, and the heat treatment process is omitted, which is conducive to energy conservation and emission reduction of enterprises, is easier to industrialize continuous and efficient production, has strong practicality, and is worthy of application and promotion.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A production method for improving the yield of nickel-steel composite plates comprises continuous casting steel billet opening treatment, nickel-based alloy plate pre-preparation, nickel-steel composite plate assembly treatment, nickel-steel composite plate billet rolling treatment, and nickel-steel composite plate billet separation treatment.

[0006] The continuous casting steel billet opening process includes the following specific contents: the heated continuous casting steel billet is transported to a high-pressure water dephosphorization machine through a roller table to complete dephosphorization, and then transported to a rough rolling mill, and a multi-pass large reduction is adopted, the reduction passes are 2 to 4 passes, and the single-pass reduction amount is ≥20%, so as to effectively break and refine the large-sized grains formed in the continuous casting and heating process of the steel billet; after the rough rolling is completed, the high-pressure water spray device provided between the rough rolling mill and the finishing rolling mill is used for rapid cooling, and the cooling rate is 10 to 30°C / s, so as to remove the oxide scale on the surface of the steel billet and inhibit the abnormal growth of the grains in the steel billet at high temperature.

[0007] The nickel-based alloy plate pre-preparation includes the following specific contents: the nickel-based alloy plate is pre-rolled by a rolling mill equipped with a large edge reduction and a small core reduction; the edge of the nickel-based alloy plate after rolling is a trapezoid, the thickness gradually increases from the edge to the core, and is smaller than the size of the steel billet after blanking in the length and width directions, the edge thickness of the nickel-based alloy plate after rolling is (0.6-0.8)h, h is the target thickness of the nickel-based alloy plate rolling, the trapezoid is a right-angle trapezoid, and the height of the trapezoid is (1-4)h. The nickel-based alloy plate billet assembly process before the subsequent vacuum electron beam welding is realized without cutting or with less cutting, and a small-sized nickel-based alloy can be selected to obtain a billet of the required size after rolling, which saves expensive nickel-based alloy materials while improving the billet assembly efficiency and reduces the production cost.

[0008] The nickel-steel composite plate assembly process comprises: further grinding and flattening the surfaces of the steel billet and the nickel-based alloy slab after blanking, removing pollutants such as oxides and oil stains, and ensuring the surface smoothness and flatness; evenly applying an isolating agent on the surfaces of two nickel-based alloy slabs and buckling them together, which is beneficial to the subsequent separation of the composite slabs, and performing vacuum electron beam welding on the four sides of the processed nickel-based alloy slabs; cutting a groove from the steel billet after blanking, placing the welded nickel-based alloy slab into the steel billet groove, wherein the cutting shape of the steel billet groove matches the shape of the nickel-based alloy, and the cutting size is slightly larger than the nickel-based alloy slab, which is convenient for positioning and separation of the composite plate after rolling; after blanking by adopting the billet-nickel-based alloy slab-nickel-based alloy slab-steel billet assembly method, the billet is sent to a vacuum electron beam welding device to perform vacuum electron beam welding on the four sides of the billet to obtain a nickel-steel composite slab; after welding is completed, whether the welding effect of the prepared composite slab meets the requirements is detected.

[0009] The nickel-steel composite slab rolling process comprises: placing the nickel-steel composite slab into a heating furnace for preheating treatment; subsequently, passing the preheated nickel-steel composite slab through a roller conveyor and a high-pressure water dephosphorization machine and a rolling mill for dephosphorization and controlled rolling operations; after rolling is completed, quickly transporting the nickel-steel composite slab to a water cooling device for controlled cooling operations, and after straightening at a straightening machine, transferring to a cooling bed to cool to room temperature.

[0010] The preheating temperature of the heating furnace is 1200-1300°C, the final rolling temperature of the controlled rolling operation is not less than 1000°C; the red-returning temperature of the controlled cooling operation is between 650-680°C.

[0011] The nickel-steel composite slab separation process includes: using flaw detection equipment to perform flaw detection on the nickel-steel composite slab. Since the cutting size of the steel billet groove during the assembly process is slightly larger than that of the nickel-based alloy slab, it is easier to find the boundary of the nickel-steel composite plate during the flaw detection process; in order to prevent the composite layer from being damaged during the separation process, plasma cutting is used to cut along the boundaries of the four sides of the nickel-steel composite plate, and finally two high-quality nickel-steel composite plates are obtained through a plate turning machine.

[0012] The heating temperature of the continuous casting steel billet is 1150-1250°C.

[0013] The nickel-steel composite plate is a composite plate prepared by using 370-420MPa grade bridge steel and nickel-based alloy.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The present invention adopts multiple large-pass pressing to open the steel billet, greatly refines the grains, and uses the high-pressure water spray device improved on the rough rolling mill to quickly cool down, and simultaneously realizes the removal of the oxide scale on the surface of the steel billet and the control of the internal grain size, which is beneficial to the refinement of the grains of the composite layer of the product after the composite slab is rolled, and improves the comprehensive mechanical properties of the product.

[0016] 2. The present invention adopts a rolling process to pre-treat the nickel-based alloy plate, avoiding the waste of raw materials caused by a large amount of cutting processing in the process of conventional machining to prepare plates of the same shape; compared with the original-size nickel-based alloy plate, the plate is pre-prepared by rolling deformation instead of machining, which refines the grain structure of the nickel-based alloy plate, and a smaller-sized nickel-based alloy plate can be used as raw material, reducing the production cost of the composite plate and improving production efficiency.

[0017] 3. The various processes of the nickel-steel composite plate prepared by the present invention are closely connected, and the thickness of the nickel-based alloy side of the composite layer of the product is evenly distributed from the edge to the core, which greatly reduces the problem of uneven thickness of the nickel-based alloy side of the product after rolling, and at the same time reduces the cutting length of the head, tail and edge of the nickel-steel composite plate, significantly improving the yield and finished product rate of the nickel-steel composite plate; at the same time, a nickel-steel composite plate with excellent comprehensive performance can be obtained through a controlled rolling and controlled cooling process, eliminating the subsequent heat treatment process, which is beneficial to energy conservation and emission reduction of enterprises, is easier to industrialize continuous and efficient production, has strong practicality, and is worthy of application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the assembly of the nickel-steel composite slab in the present invention.

[0019] 1. Steel billet, 2. Nickel-based composite slab. DETAILED DESCRIPTION

[0020] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are used to specifically illustrate the contents of the present invention. These examples are only general descriptions of the contents of the present invention and do not limit the contents of the present invention.

[0021] Example 1: In Example 1 of the present invention, the substrate and the composite material respectively use Q370 grade high-strength low-alloy bridge structure steel and GH625 nickel-based alloy, and the specific method includes the following steps:

[0022] 1. Processing of continuous casting billet:

[0023] The Q370 bridge steel continuous casting billet is preheated in a heating furnace at a preheating temperature of 1200°C. After preheating, it is transported to a high-pressure water dephosphorization machine via a roller table to complete dephosphorization, and then transported to a rough rolling mill. Two passes of large reduction are used, with a single pass reduction of 30%, to effectively crush and refine the large-sized grains of the Q370 bridge steel continuous casting billet formed during the continuous casting and heating process. After the rough rolling is completed, the high-pressure water spray device improved and installed between the rough rolling mill and the finishing rolling mill is used for rapid cooling, with a cooling rate of 15°C / s, to remove the oxide scale on the surface of the billet while preventing the abnormal growth of the grains in the billet at high temperatures.

[0024] 2. Pre-preparation of nickel-based alloy plates:

[0025] The GH625 nickel-based alloy plate is pre-treated by rolling using a small roller mill with large edge reduction and core reduction. The edge of the rolled GH625 nickel-based alloy plate is trapezoidal, and the thickness gradually increases from the edge to the core, and is smaller than the size of Q370 bridge steel after blanking in the length and width directions, which is beneficial to the blanking process of the GH625 nickel-based alloy plate before the subsequent vacuum electron beam welding without cutting or with less cutting, which improves the blanking efficiency while saving expensive nickel-based alloy materials and reducing the production cost.

[0026] h is the target rolling thickness of the nickel-based alloy plate, h=5 mm. The edge thickness of the nickel-based alloy plate after rolling is 3.5 mm. The trapezoid is a right-angle trapezoid, and the height of the trapezoid is 15 mm.

[0027] 3. Nickel steel composite plate assembly processing:

[0028] The surfaces of the Q370 bridge steel and GH625 nickel-based alloy slabs are further polished and flattened to remove pollutants such as oxides and oil stains to ensure surface finish and flatness; an isolating agent is evenly applied to the surfaces of the two GH625 nickel-based alloy slabs to facilitate the subsequent separation of the composite slabs, and the four sides of the processed GH625 nickel-based alloy slabs are subjected to vacuum electron beam welding; the welded GH625 nickel-based alloy slabs are placed in the pre-cut Q370 bridge steel billet, the inner surface cutting shape of the Q370 bridge steel billet matches the shape of the GH625 nickel-based alloy, and the cutting size is slightly larger than the GH625 nickel-based alloy slab, which is convenient for positioning and separation of the composite plate after rolling; after the billet is assembled in the manner of Q370 bridge steel-GH625 nickel-based alloy-GH625 nickel-based alloy-Q370 bridge steel, it is sent to the vacuum electron beam welding equipment to perform vacuum electron beam welding on the four sides of the billet; after the welding is completed, whether the welding effect of the prepared composite slab meets the requirements is detected.

[0029] 4. Nickel steel composite slab rolling process:

[0030] The nickel-steel composite slab is placed in a heating furnace for preheating treatment at a temperature of 1250°C. Subsequently, the preheated nickel-steel composite slab is passed through a roller conveyor and a high-pressure water dephosphorization machine and a rolling mill for dephosphorization and controlled rolling, with a final rolling temperature of no less than 1100°C. After rolling, the nickel-steel composite slab is quickly transported to a water cooling device for controlled cooling, with a return temperature of 660°C. After straightening at a straightening machine, it is transferred to a cooling bed and cooled to room temperature.

[0031] 5. Nickel steel composite slab separation process:

[0032] The nickel-steel composite slab is inspected by flaw detection equipment. Since the cutting size of the steel slab during the assembly process is slightly larger than that of the nickel-based alloy slab, it is easier to find the boundary of the nickel-steel composite plate during the flaw detection process. In order to prevent the composite layer from being damaged during the plate separation process, plasma cutting is used to cut along the boundaries of the four sides of the nickel-steel composite plate, and finally two nickel-steel composite plates are obtained through a plate turning machine.

[0033] Example 2: In Example 2 of the present invention, the substrate and the composite material respectively use Q420 grade high-strength low-alloy bridge structure steel and GH600 nickel-based alloy, including the following steps:

[0034] 1. Processing of continuous casting billet:

[0035] The Q420 bridge steel continuous casting billet is preheated in a heating furnace at a preheating temperature of 1180°C. After preheating, it is transported to a high-pressure water dephosphorization machine via a roller table to complete dephosphorization, and then transported to a rough rolling mill. Four passes of large reduction are used, with a single pass reduction of 20%, to effectively crush and refine the large-sized grains of the Q420 bridge steel continuous casting billet formed during the continuous casting and heating process. After the rough rolling is completed, the high-pressure water spray device improved and installed between the rough rolling mill and the finishing rolling mill is used for rapid cooling, with a cooling rate of 20°C / s, to remove the oxide scale on the surface of the billet while preventing the abnormal growth of the grains in the billet at high temperatures.

[0036] 2. Pre-preparation of nickel-based alloy plates:

[0037] The GH600 nickel-based alloy plate is pre-treated by rolling using a small roller mill with large edge reduction and core reduction. The edge of the GH600 nickel-based alloy plate after rolling is trapezoidal, and the thickness gradually increases from the edge to the core, and is smaller than the size of Q420 bridge steel after blanking in the length and width directions, which is beneficial to the blanking process of the GH600 nickel-based alloy plate before the subsequent vacuum electron beam welding without cutting or less cutting, which improves the blanking efficiency while saving expensive nickel-based alloy materials and reducing production costs.

[0038] h is the target rolling thickness of the nickel-based alloy plate, h=3 mm. The edge thickness of the nickel-based alloy plate after rolling is 2 mm. The trapezoid is a right-angle trapezoid, and the height of the trapezoid is 12 mm.

[0039] 3. Nickel steel composite plate assembly processing:

[0040] The surfaces of the Q420 bridge steel and GH600 nickel-based alloy slabs are further polished and flattened to remove pollutants such as oxides and oil stains to ensure surface finish and flatness; an isolating agent is evenly applied to the surfaces of the two GH600 nickel-based alloy slabs to facilitate the subsequent separation of the composite slabs, and the four sides of the processed GH600 nickel-based alloy slabs are subjected to vacuum electron beam welding; the welded GH600 nickel-based alloy slabs are placed into the pre-cut Q420 bridge steel billet, the inner surface cutting shape of the Q420 bridge steel billet matches the shape of the GH600 nickel-based alloy, and the cutting size is slightly larger than the GH600 nickel-based alloy slab, which is convenient for positioning and separation of the composite plate after rolling; after the billet is assembled in the manner of Q420 bridge steel-GH600 nickel-based alloy-GH600 nickel-based alloy-Q420 bridge steel, it is sent to the vacuum electron beam welding equipment to perform vacuum electron beam welding on the four sides of the billet; after the welding is completed, whether the welding effect of the prepared composite slab meets the requirements is detected.

[0041] 4. Nickel steel composite slab rolling process:

[0042] The nickel-steel composite slab is placed in a heating furnace for preheating treatment at a temperature of 1270°C. Subsequently, the preheated nickel-steel composite slab is passed through a roller conveyor and passed through a high-pressure water dephosphorization machine and a rolling mill for dephosphorization and controlled rolling, with a final rolling temperature of 1050°C. After rolling, the nickel-steel composite slab is quickly transported to a water cooling device for controlled cooling, with a return temperature between 670°C. After straightening at a straightening machine, it is transferred to a cooling bed and cooled to room temperature.

[0043] 5. Nickel steel composite slab separation process:

[0044] The nickel-steel composite slab is inspected by flaw detection equipment. Since the cutting size of the steel slab during the assembly process is slightly larger than that of the nickel-based alloy slab, it is easier to find the boundary of the nickel-steel composite plate during the flaw detection process. In order to prevent the composite layer from being damaged during the plate separation process, plasma cutting is used to cut along the boundaries of the four sides of the nickel-steel composite plate, and finally two nickel-steel composite plates are obtained through a plate turning machine.

[0045] The present invention adopts multiple large-pass pressing to open the steel billet, and uses the high-pressure water spray device improved on the rough rolling mill to quickly cool down, and simultaneously realizes the removal of oxide scale on the surface of the steel billet and the control of the internal grain size, which is beneficial to the refinement of the grains of the composite layer of the product after the composite plate billet is rolled, and improves the comprehensive mechanical properties of the product; the rolling process is adopted to pre-treat the nickel-based alloy plate, thereby avoiding the waste of raw materials caused by a large amount of cutting processing in the process of conventional machining to prepare plates of the same shape; compared with the original-size nickel-based alloy plate, the plate is pre-prepared by rolling deformation instead of machining, and a smaller-sized nickel-based alloy plate can be used as the raw material, reducing The production cost of the composite plate is reduced and the production efficiency is improved. The various processes of the nickel-steel composite plate prepared by the present invention are closely connected, and the thickness of the nickel-based alloy side of the composite layer of the product is evenly distributed from the edge to the core, which greatly reduces the problem of uneven thickness of the nickel-based alloy side of the product after rolling, and at the same time reduces the cutting length of the head, tail and edge of the nickel-steel composite plate, significantly improving the yield and finished product rate of the nickel-steel composite plate. At the same time, the nickel-steel composite plate with excellent comprehensive performance can be obtained through the controlled rolling and controlled cooling process, eliminating the subsequent heat treatment process, which is beneficial to energy conservation and emission reduction of enterprises, is easier to industrialize continuous and efficient production, has strong practicality, and is worthy of application and promotion.

Claims

1. A production method for improving the yield of nickel-steel composite plates, characterized in that: The method comprises the following steps: removing phosphorus from the heated continuous casting billet by high-pressure water, and then transporting the heated continuous casting billet to a rough rolling mill, and adopting multi-pass large reduction, wherein the reduction passes are 2 to 4, and the reduction amount of a single pass is ≥20%; after the rough rolling is completed, high-pressure water spraying is used to quickly cool the billet, and the cooling rate is 10 to 30°C / s; The pre-preparation of the nickel-based alloy plate includes the following specific contents: the nickel-based alloy plate is pre-rolled using a roller mill with a large edge reduction and a small core reduction; the edge of the nickel-based alloy plate after rolling is a trapezoid, the thickness gradually increases from the edge to the core, and is smaller than the size of the steel billet after blanking in the length and width directions, the edge thickness of the nickel-based alloy plate after rolling is (0.6~0.8)h, h is the target rolling thickness of the nickel-based alloy plate, the trapezoid is a right-angle trapezoid, and the trapezoid height is (1~4)h.

2. A method for improving the yield of nickel-steel composite plates according to claim 1, characterized in that: The nickel-steel composite plate assembly process comprises: evenly applying an isolating agent on the surfaces of two nickel-based alloy plate billets and buckling them together, and performing vacuum electron beam welding on the four sides; cutting a groove on the billet after blanking, placing the welded nickel-based alloy plate billet into the billet groove, wherein the cutting shape of the billet groove matches the shape of the nickel-based alloy, and the cutting size is larger than the nickel-based alloy plate billet, and after the billet is assembled in the billet-nickel-based alloy plate billet-nickel-based alloy plate billet-steel billet assembly mode, vacuum electron beam welding is performed on the four sides of the billet to obtain the nickel-steel composite plate billet.

3. A production method for improving the yield of nickel-steel composite plates according to claim 1, characterized in that: The nickel-steel composite slab rolling process comprises: placing the nickel-steel composite slab into a heating furnace for preheating treatment; then undergoing high-pressure water dephosphorization and controlled rolling operations; after rolling is completed, performing controlled cooling operations, straightening at a straightening machine, and then transferring to a cooling bed to cool to room temperature.

4. A production method for improving the yield of nickel-steel composite plates according to claim 3, characterized in that: The preheating temperature of the heating furnace is 1200-1300°C, the final rolling temperature of the controlled rolling operation is not less than 1000°C; the red-returning temperature of the controlled cooling operation is between 650-680°C.

5. A production method for improving the yield of nickel-steel composite plates according to claim 1, characterized in that: The nickel-steel composite plate blank separation process includes: using a flaw detection device to perform flaw detection on the nickel-steel composite plate blank to find the boundary of the nickel-steel composite plate; using plasma cutting to cut along the boundaries of the four sides of the nickel-steel composite plate, and finally obtaining two nickel-steel composite plates through a plate turning machine.

6. A production method for improving the yield of nickel-steel composite plates according to claim 1, characterized in that: The heating temperature of the continuous casting steel billet is 1150-1250°C.

7. A method for improving the yield of nickel-steel composite plates according to claim 1, characterized in that: The nickel-steel composite plate is a composite plate prepared by using 370-420MPa grade bridge steel and nickel-based alloy.

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