Forming process for manufacturing large flat plate type casting blank based on wide and thick continuous casting blank

Abstract

The invention belongs to the technical field of steel rolling, and particularly provides a forming process for manufacturing a large flat plate type casting blank based on a wide and thick continuous casting blank. S2, the treated molten steel is injected into a continuous casting machine to be cast into a plate-shaped continuous casting blank; s3, scribing is carried out; s4, punching is carried out; s5, cutting is conducted; s6, the cut plate-shaped continuous casting billet is checked; s7, repairing the plate-shaped continuous casting billet which is checked to have problems, and finishing the forming processing of the plate-shaped continuous casting billet after the plate-shaped continuous casting billet is repaired to meet the requirements; the problems that a traditional die casting blank casting mode is adopted for production of an existing rolling mill housing, efficiency is low, machining procedures are tedious, quality is not high, and high-efficiency and high-quality batch production of the rolling mill housing cannot be achieved are solved. The continuous casting blank is adopted for casting, the yield is high, the cost is low, the energy consumption is low, the structure performance is stable, the production efficiency and the product quality of the rolling mill housing are improved, and high-efficiency and high-quality batch production of the rolling mill housing is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of steel rolling, and in particular relates to a forming process for manufacturing a large flat-plate casting blank based on a wide and thick continuous casting blank. Background Art

[0002] The mill arch, also known as the frame or frame, is one of the most critical and difficult parts in the mill production process. The mill arch is widely used in the metallurgical industry and has a direct impact on the mill's operating stability, product quality, production efficiency and equipment life. It is an indispensable key component in the mill and plays a decisive role in the entire steel production process.

[0003] The rolling mill arch is a large component, and the blank is usually cast by integral casting. Since this processing procedure is relatively cumbersome, it will cause a lot of waste of manpower and material resources. And due to the limitations of the casting process, defects such as inclusions and shrinkage holes may occur, affecting the quality and performance of the casting.

[0004] The Chinese patent with publication number CN113250236A provides a method for casting the foundation of a vertical rolling mill archway, which ensures the structural reliability of the vertical rolling mill archway, improves the appearance quality of the concrete casting, reduces the cost of later repairs, and improves the economic benefits of the project.

[0005] The Chinese patent with publication number CN111545748A provides a composite manufacturing method for a rolling mill arch. First, medium-carbon low-alloy steel liquid is smelted in an electric arc furnace, and then the molten steel is cast into a rolling mill arch blank using a water glass sand mold. After the rolling mill arch blank is rough-processed and normalized, the CMT arc additive manufacturing method is used. The cold metal transition arc is used as the heat source. Through the melting of the welding wire, it is deposited layer by layer on the working part of the rolling mill arch to manufacture a wear-resistant and corrosion-resistant coating with a thickness of 10.0-12.0 mm. A rolling mill arch with good wear and corrosion resistance is obtained. The service life is more than 3 times that of an ordinary cast steel rolling mill arch. It can also improve the precision of the rolled material and reduce the labor intensity of workers. The promotion and application of this method has good economic and social benefits.

[0006] The Chinese patent with publication number CN104646965B provides a processing technology for a twenty-high rolling mill arch, which includes blank casting, annealing, rough machining of each surface and plum blossom holes, flaw detection, normalizing, semi-finishing of each surface and plum blossom holes, aging treatment, plum blossom hole finishing and surface forming, superfine grinding, testing and rust prevention treatment, and finally the processing and manufacturing are completed.

[0007] The above method has further improved the original process, or invented a new process, perfected the processing method of the rolling mill arch, and improved the quality and service life of the rolling mill arch. However, in the above method, the production of the rolling mill arch still remains in the traditional casting method, which has problems such as low efficiency, complicated processing procedures, and low quality. It is even more impossible to achieve high-efficiency and high-quality mass production of the rolling mill arch. Summary of the invention

[0008] The present invention provides a forming process for producing large flat-plate casting blanks based on wide and thick continuous casting billets, with the aim of overcoming the problems of low efficiency, complicated processing procedures and low quality in the production of rolling mill arches in the prior art, which makes it impossible to achieve high-efficiency and high-quality mass production of rolling mill arches.

[0009] To this end, the present invention provides a forming process for manufacturing a large flat-plate casting blank based on a wide and thick continuous casting blank, comprising the following steps:

[0010] S1. Smelting: Processing of molten steel;

[0011] S2, continuous casting: inject the treated molten steel into the continuous casting machine to cast into plate-shaped continuous casting billets;

[0012] S3. Marking: Mark the cutting line on the plate-shaped continuous casting billet according to the design requirements;

[0013] S4, punching: punch holes on the plate-shaped continuous casting billet according to design requirements;

[0014] S5, cutting: cutting on the plate-shaped continuous casting billet according to the cutting line;

[0015] S6. Inspect the cut plate-shaped continuous casting billet;

[0016] S7. Repair the plate-shaped continuous casting billet that has problems during inspection until it meets the requirements, and then complete the forming process of the plate-shaped continuous casting billet.

[0017] Preferably, during the smelting, when the arch material is ZG270-500, the pouring temperature is 1535±10°C.

[0018] Preferably, when the arch material is ZG270-500, after the molten steel is treated, the chemical elements in the molten steel are required to be controlled within the following ranges: C≤0.4%, Si≤0.5%, Mn≤0.9%, S≤0.04%, P≤0.04%, and the residual element content≤1%.

[0019] Preferably, during the smelting, when the arch material is GS20Mn5V, the pouring temperature is 1585±10°C.

[0020] Preferably, when the arch material is GS20Mn5V, after the molten steel is treated, the chemical elements in the molten steel are required to be controlled within the following ranges: 0.17%≤C≤0.23%, Si≤0.6%, 1%≤Mn≤1.5%, S≤0.015%, P≤0.02%, Cr≤0.3%, and Ni≤0.4%.

[0021] Preferably, during the drilling, holes are drilled at four corners of the plate-shaped continuous casting billet.

[0022] Preferably, the cutting is carried out by oxyhydrogen flame cutting.

[0023] Preferably, the gap formed by the oxyhydrogen flame cutting is within 4.5 mm.

[0024] Preferably, during the cutting, a processing allowance is reserved.

[0025] Preferably, the machining allowance is 25-30 mm.

[0026] Beneficial effects of the present invention:

[0027] 1. The forming process for making large flat casting blanks based on wide and thick continuous casting blanks provided by the present invention comprises the following steps: S1, smelting: treating molten steel; S2, continuous casting: injecting the treated molten steel into a continuous casting machine to cast a plate-shaped continuous casting blank; S3, marking: marking cutting lines on the plate-shaped continuous casting blank according to design requirements; S4, punching: punching holes on the plate-shaped continuous casting blank according to design requirements; S5, cutting: cutting on the plate-shaped continuous casting blank according to the cutting lines; S6, inspecting the cut plate-shaped continuous casting blank; S7, repairing the plate-shaped continuous casting blank with problems in the inspection, and completing the forming process of the plate-shaped continuous casting blank after the repair meets the requirements; adopting continuous casting blank casting to replace the mold casting blank casting adopted in the traditional process, giving full play to the characteristics of continuous casting blanks with high yield, low cost, low energy consumption, stable organizational performance, etc., reducing costs from both process and raw material aspects, and greatly improving the production efficiency and product quality of the rolling mill arch, realizing high-efficiency and high-quality mass production of the rolling mill arch.

[0028] 2. The forming process for producing large flat-plate casting blanks based on wide and thick continuous casting blanks provided by the present invention ensures the purity of steel and improves product quality by treating molten steel during smelting.

[0029] 3. In the forming process for producing large flat-plate casting blanks based on wide and thick continuous casting blanks provided by the present invention, holes are punched at the four corners of the plate-shaped continuous casting blanks to ensure positioning accuracy and prepare for subsequent cutting processing.

[0030] 4. The forming process of the present invention for making large flat-plate casting blanks based on wide and thick continuous casting blanks adopts hydrogen-oxygen flame cutting during cutting. The hydrogen-oxygen flame cutting has a fast speed and high cutting efficiency, and can better adapt to high-intensity production rhythm during continuous casting. It has small spatter, small heat-affected zone, narrow cutting seam, and reduced cutting loss compared with natural gas cutting, and increased blank output. The cutting surface is flat and smooth, with less burrs and slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] Figure 1 It is a schematic diagram of the process of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of a plate-shaped continuous casting billet;

[0034] Figure 3 It is a schematic diagram of the blank structure of the rolling mill arch.

[0035] Explanation of the accompanying drawings: 1. Plate-shaped continuous casting billet; 2. Rolling mill arch billet. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] Embodiment 1:

[0038] like Figure 1 As shown, a forming process for producing a large flat casting blank based on a wide and thick continuous casting blank comprises the following steps:

[0039] S1. Smelting: Processing of molten steel;

[0040] S2, continuous casting: inject the treated molten steel into a continuous casting machine to cast into a plate-shaped continuous casting billet; specifically, the shape of the plate-shaped continuous casting billet 1 can be seen in Figure 2 ;

[0041] S3. Marking: Mark the cutting line on the plate-shaped continuous casting billet according to the design requirements;

[0042] S4, punching: punch holes on the plate-shaped continuous casting billet according to design requirements;

[0043] S5, cutting: cutting on the plate-shaped continuous casting billet according to the cutting line;

[0044] S6. Inspect the cut plate-shaped continuous casting billet;

[0045] S7, repair the plate-shaped continuous casting billet with problems, and complete the forming process of the plate-shaped continuous casting billet after the repair meets the requirements. Specifically, the shape of the plate-shaped continuous casting billet (rolling mill blank 2) after the forming process is as follows Figure 3 , Figure 3 This is just an example. In actual operation, it is not limited to Figure 3 As shown, it can be processed according to actual conditions.

[0046] The present invention adopts continuous casting billet casting to replace the mold casting billet casting adopted in the traditional process, giving full play to the characteristics of continuous casting billet such as high yield rate, low cost, low energy consumption, stable organizational performance, etc., reducing costs from both process and raw material aspects, and greatly improving the production efficiency and product quality of the rolling mill, thereby realizing high-efficiency and high-quality mass production of the rolling mill.

[0047] Embodiment 2:

[0048] On the basis of Example 1, during the smelting, when the arch material is ZG270-500, the pouring temperature is 1535±10°C.

[0049] Specifically, ZG270-500 is a type of medium carbon cast steel, which has certain toughness and plasticity, high strength and hardness, and good machinability. During smelting, because the arch material is ZG270-500, the melting point is about 1450°C, so the pouring temperature is determined to be 1535±10°C, so that the molten steel has an overheat of about 85°C when pouring, ensuring that the molten steel still maintains a sufficient temperature during pouring, so as to prevent defects caused by temperature drop during the solidification process of the molten steel, and ensure the quality of smelting products and production efficiency.

[0050] Preferably, when the arch material is ZG270-500, after the molten steel is treated, the mass percentage of each chemical element in the molten steel is required to be controlled within the following range: C≤0.4%, Si≤0.5%, Mn≤0.9%, S≤0.04%, P≤0.04%, and residual element content≤1%.

[0051] Specifically, the molten steel is subjected to processes such as deoxidation and desulfurization to ensure the purity of the steel and improve product quality. C is carbon, Mn is manganese, S is sulfur, and P is phosphorus. Residual elements refer to impurity elements that have not been completely removed during the steelmaking process. During the steelmaking process, steelmaking raw materials (including molten iron, scrap steel, and ferroalloys, etc.) will bring a large amount of impurity elements into the steelmaking furnace, some of which can be removed, but some impurity elements will still remain in the steel. This part of impurities (non-intentionally added alloy elements) is collectively referred to as residual elements. The present invention does not limit the specific types of residual elements.

[0052] Embodiment 3:

[0053] On the basis of Example 2, during the smelting, when the arch material is GS20Mn5V, the pouring temperature is 1585±10°C.

[0054] Specifically, the chemical composition of GS20Mn5V includes the following elements in mass percentage: C: 0.17-0.23%, Si≤0.60%, Mn: 1.00-1.50%, P≤0.020%, S≤0.015%, Cr≤0.30%, Mo≤0.15%, Ni≤0.40%, wherein C is carbon, Si is silicon, Mn is manganese, P is phosphorus, S is sulfur, Cr is chromium, Mo is molybdenum, and Ni is nickel. This material is clearly defined in the German standard DIN17182, and there is also a corresponding grade ZG20SiMn in China. During smelting, the arch material is GS20Mn5V, and the melting point is about 1500℃, so the pouring temperature is determined to be 1585±10℃, so that the molten steel has an overheat of about 85℃ when pouring, ensuring that the molten steel still maintains a sufficient temperature during pouring to prevent defects caused by temperature drop during the solidification process of the molten steel, and to ensure the product quality and production efficiency of the smelting products.

[0055] Preferably, when the arch material is GS20Mn5V, after the molten steel is treated, the mass percentage of each chemical element in the molten steel is required to be controlled within the following range: 0.17%≤C≤0.23%, Si≤0.6%, 1%≤Mn≤1.5%, S≤0.015%, P≤0.02%, Cr≤0.3%, Ni≤0.4%.

[0056] Specifically, the molten steel is deoxidized and desulfurized to control the chemical elements in the molten steel within the specified range, ensure the purity of the steel, and improve the product quality. C is carbon, Si is silicon, Mn is manganese, S is sulfur, P is phosphorus, Cr is chromium, and Ni is nickel.

[0057] Embodiment 4:

[0058] On the basis of Example 3, during the continuous casting, the plate-shaped continuous casting billet has the following dimensions: thickness 400 mm, length 3800 mm, width 2500 mm. The specific dimensions can be selected according to the requirements.

[0059] Embodiment 5:

[0060] On the basis of Example 4, the cutting lines are drawn on the plate-shaped continuous casting billet. During the marking process, it is required to comprehensively check the outer dimensions of the cast plate-shaped continuous casting billet and allocate the allowance of each processed surface.

[0061] Specifically, the marking process includes a comprehensive inspection of the outer dimensions of the plate-shaped continuous casting billet and a reasonable allocation of the allowance of each processed surface to ensure that the processed surface has an allowance and the relative position of the processed surface and the unprocessed surface is correct.

[0062] Preferably, the marking is performed using an automated marking device to ensure the accuracy of the cutting line.

[0063] Embodiment 6:

[0064] On the basis of Example 5, during the drilling, holes are drilled at the four corners of the plate-shaped continuous casting billet.

[0065] Specifically, a floor-standing CNC boring and milling machine is used to drill holes at the four corners of the plate-shaped continuous casting billet to ensure positioning accuracy and prepare for subsequent cutting processing.

[0066] Embodiment 7:

[0067] On the basis of Example 6, hydrogen-oxygen flame cutting is adopted during the cutting.

[0068] Specifically, during the cutting process, hydrogen-oxygen flame cutting is selected, and the power supply is 380V AC. After being processed by the transformer and rectifier, the DC power is output to the hydrogen-oxygen generator. Hydrogen-oxygen cutting has a fast speed and high cutting efficiency, and can better adapt to the high-intensity production rhythm during continuous casting; it has small spatter, small heat-affected zone, and narrow cutting seam. Compared with natural gas cutting, the cutting seam loss is reduced and the billet output is increased; the cutting surface is flat and smooth, with less burrs and slag.

[0069] Embodiment 8:

[0070] Based on Example 7, the gap of the oxyhydrogen flame cutting is within 4.5 mm.

[0071] Specifically, the spacing gap is within 4.5 mm, which improves the cutting quality and the dimensional accuracy of the continuous casting billet and reduces material loss.

[0072] Preferably, during the cutting, a processing allowance is reserved.

[0073] Specifically, reserving appropriate machining allowances can compensate for manufacturing errors, remove surface defects, improve surface roughness, compensate for clamping errors, and improve machining efficiency, thereby ensuring the quality and performance of the final product.

[0074] Preferably, the machining allowance is 25-30 mm.

[0075] Specifically, when determining the machining allowance, it is considered that the cutting surface will produce a certain deformation due to heat, and it is also prepared for subsequent processing, so the machining allowance is 25-30mm.

[0076] Preferably, the problematic plate-shaped continuous casting billet includes size problems, surface defects or structural problems. The size problems are repaired by milling using a CNC floor-standing boring and milling machine; the surface defects or structural problems are repaired by welding.

[0077] Specifically, after the size and quality of the repaired plate-shaped continuous casting billet meet the requirements, the processing is completed and the billet is delivered to ensure product quality.

[0078] In the description of the present invention, it should be understood that if any term indicates an orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention.

[0079] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A forming process for producing large flat-plate casting blanks based on wide and thick continuous casting blanks, characterized in that: The steps include: S1. Smelting: Processing of molten steel; S2, continuous casting: inject the treated molten steel into the continuous casting machine to cast into plate-shaped continuous casting billets; S3, marking: according to the design requirements, cut the cutting line on the plate-shaped continuous casting billet; S4, punching: punch holes on the plate-shaped continuous casting billet according to design requirements; S5, cutting: cutting on the plate-shaped continuous casting billet according to the cutting line; S6. Inspect the cut plate-shaped continuous casting billet; S7. Repair the plate-shaped continuous casting billet that has problems during inspection until it meets the requirements, and then complete the forming process of the plate-shaped continuous casting billet.

2. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 1, characterized in that: During the smelting, when the arch material is ZG270-500, the pouring temperature is 1535±10℃.

3. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 2, characterized in that: When the arch material is ZG270-500, after the molten steel is treated, the chemical elements in the molten steel are required to be controlled within the following ranges: C≤0.4%, Si≤0.5%, Mn≤0.9%, S≤0.04%, P≤0.04%, and the residual element content≤1%.

4. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 1, characterized in that: During the smelting, when the arch material is GS20Mn5V, the pouring temperature is 1585±10℃.

5. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 4, characterized in that: When the arch material is GS20Mn5V, after the molten steel is treated, the chemical elements in the molten steel are required to be controlled within the following ranges: 0.17%≤C≤0.23%, Si≤0.6%, 1%≤Mn≤1.5%, S≤0.015%, P≤0.02%, Cr≤0.3%, and Ni≤0.4%.

6. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 1, characterized in that: During the punching, holes are punched at four corners of the plate-shaped continuous casting billet.

7. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in any one of claims 3 or 5, characterized in that: The cutting is carried out by using hydrogen-oxygen flame cutting.

8. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 7, characterized in that: The gap of the oxyhydrogen flame cutting is within 4.5 mm.

9. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 8, characterized in that: During the cutting, a processing allowance is reserved.

10. The forming process for producing a large flat-plate casting blank based on a wide and thick continuous casting blank as claimed in claim 9, characterized in that: The processing allowance is 25-30 mm.

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