Preparation method of high-carbon damping vibration reduction steel and melting and casting device thereof

Abstract

The application relates to a preparation method of high-carbon damping vibration reduction steel and a melting and casting device thereof, and belongs to the field of structure-function integrated engineering materials. The application adopts a combined casting mode of vacuum induction melting and centrifugal casting, utilizes a composite shear flow technology, combines subsequent controlled rolling and controlled cooling and heat treatment technologies, and shortens the heat treatment time of the high-carbon damping vibration reduction steel. The application comprises a composite shear flow casting-rolling-heat treatment process. The application can greatly shorten the subsequent graphitization heat treatment time of the vibration reduction steel, optimizes the performance, and saves the cost. The application has important significance for the popularization and application of the high-carbon damping vibration reduction steel.

Description

[0001] The present application claims priority to application number 202210856214.3, application date 20220721, and invention title "Preparation method of high-carbon damping vibration reduction steel and its smelting and casting device". TECHNICAL FIELD

[0002] The present application relates to a preparation method of high-carbon damping vibration reduction steel and its smelting and casting device, belonging to the technical field of structural and functional integrated engineering materials. BACKGROUND

[0003] With the continuous development of science and technology, people's requirements for working environment are also constantly improving, and noise as a common source of pollution in work is increasingly valued by people, so developing vibration reduction materials that meet working performance has become a key direction of current material development [Document one: Du Guofang, Shan Changji, Cai Yan, Yang Haitao. On vibration reduction and noise reduction materials [J]. Scientific and Technological Innovation, 2018(32): 189-190].

[0004] The current ideas of vibration and noise reduction can be divided into three categories: one is to design parts or change the mechanical structure to isolate the vibration source from the surrounding structure parts, so as to prevent the vibration from radiating and spreading to the surrounding, or to dissipate the vibration before it spreads. Such design will inevitably increase the volume of the structure, and increase the cost [Document two: Li Xiangzhou. Damping alloy (I) [J]. Metal World, 1995, (5): 10-11]. The second is to design a coating on the surface of the material to achieve the effect of reducing vibration without changing the performance of the material [Document three: Chen Yu gang, Zhu Qing yu, Zhai Jingyu. Experimental investigation on fatigue of blade specimen subjected to resonance and effect of a damping hard coating treatment [J]. Journal of Central South University, 2021, 28(2)]. The third is to directly change the performance of the material, or to design a new structural material to meet the use requirements and vibration reduction requirements at the same time, and to reduce the production cost, which is the main design idea of the current damping material [Document four: Jaydeep M. Karandikar, Christopher T. Value of information-based experimental design: Application to process damping in milling [J]. Precision Engineering, 2014, 38: 799-808].

[0005] Vibration and noise reduction in marine ships is a very important task, and developing high-performance materials with damping properties is a problem that needs to be solved. Steel has excellent comprehensive performance, low production cost and wide application range. The current structural material is still mainly steel. The base of the through-hull pump for ships is made of traditional carbon structural steel as the structural material, and its damping loss factor Q -1Less than 0.01, poor damping performance, need to find its replacement steel material [document five: Yu Xueyong, Liu Li, Yang Li, Guo Guolin. Damping mechanism of damping cast iron, iron manganese alloy and iron chromium aluminum alloy [J]. Hot working technology, 2016, 45 (04): 79-80 + 83. ] If a large amount of graphite is precipitated through the steel graphitization process, the steel can improve its damping performance while ensuring excellent mechanical properties, so as to optimize the mechanical properties and damping performance, play a role in damping and noise reduction, and meet the use requirements. "A kind of structure function integration high carbon damping damping steel and its preparation method" (patent number: CN113355603A), the complex phase high carbon damping damping steel in the invention has excellent mechanical properties and damping performance, and the types of alloying elements are few, the content is low, and the raw material cost is low, but in order to achieve good mechanical properties and damping performance, a longer heat treatment time is needed.

[0006] The size and distribution of graphite have a great influence on mechanical properties and damping performance, and the graphitization during heat treatment can be affected by changing the morphology and distribution of graphite in as-cast steel, so as to optimize the mechanical properties and damping performance. In the composite shear flow casting technology invented by the research group, the size and direction of flow field during solidification are controlled to control the temperature field, the metal melt has a large supercooling degree, can nucleate explosively, can realize the uniform distribution of chemical element in different positions of the ingot, and basically has no macrosegregation; And can change the morphology, size and distribution of the second phase, so that it is more fine and uniformly dispersed; The macrostructure of the finally obtained ingot is composed of fine equiaxed dendrites and surface fine crystals [document six: Wang Tao, Chen Xiaohua, Luo Xiang. Formation of Si nanoparticle in Al matrix for Al-7wt. % Si alloy during complex shear flow casting [J]. Journal of alloys and compounds, 2018, 739: 30-34]. SUMMARY

[0007] The purpose of the present application is to prepare a high-carbon damping steel ingot by using a composite shear flow casting technology, and to subsequently heat the ingot and heat treatment, so as to prepare a high-carbon damping steel with short heat treatment time and excellent performance.

[0008] A method for preparing a high-carbon damping steel, which adopts a composite casting method combining vacuum induction melting and centrifugal casting, utilizes a composite shear flow technology, combines subsequent controlled rolling and controlled cooling and heat treatment technology, shortens the heat treatment time of high-carbon damping steel, and comprises the following steps:

[0009] (1) preparing raw materials required for smelting, the high-carbon damping steel has the following chemical composition by mass percent: C≥1.2%, Si: 1.5%-1.7%, Mn: 0.20%-0.22%, Ni: 2.15%-2.25%, Al: 0.25%-0.27%, and the balance of Fe;

[0010] (2) placing the raw materials into a crucible of a smelting system, embedding a casting mold into a centrifugal barrel, filling a refractory insulating material between the casting mold and the centrifugal barrel, and preheating the casting mold;

[0011] (3) heating and melting the raw materials in the crucible by using an induction smelting process and keeping the temperature, and pouring the alloy melt into the casting mold after the temperature keeping is completed.

[0012] (4) starting a motor to drive a bottom centrifugal disc to drive the centrifugal barrel, the centrifugal barrel and the bottom centrifugal disc moving at a set speed ratio until the alloy is completely solidified, and then taking out the cast ingot.

[0013] (5) after the cast ingot is homogenized at high temperature, rolling is performed by controlling the temperature in the rolling process.

[0014] (6) after the rolled plate is isothermally heat treated, furnace cooling treatment is performed to graphitize the rolled plate, and the high-carbon damping steel is obtained.

[0015] Further, the preheating temperature in step (2) is 150-250°C, and the time is 1-5h. The preheating of the casting mold and the filling of the refractory insulating material are to maintain a certain supercooling degree after the melt is poured into the casting mold, to avoid rapid solidification of the melt, and to ensure that the composite shear flow is applied to the alloy melt by the rotation of the bottom centrifugal disc and the centrifugal barrel. The melt is kept in a liquid state after being poured into the casting mold, so as to ensure that the composite shear flow plays a role in the solidification process of the alloy melt.

[0016] Further, the induction heating process in step (3) ensures the uniform distribution of alloy elements in the melt during the smelting process, which provides favorable conditions for the uniform nucleation and growth of crystals in the melt during the later solidification process. The induction coil functions to heat and melt the metal.

[0017] Further, the bottom centrifugal disc and the centrifugal barrel rotate in opposite directions to form a strong composite shear flow in step (4). Preferably, the bottom centrifugal disc rotates in an anticlockwise direction, and the centrifugal barrel rotates in a clockwise direction. The bottom centrifugal disc and the centrifugal barrel rotate simultaneously to form the rotation and revolution of the melt, and the composite shear flow is generated in the alloy melt during the solidification process; the composite shear flow promotes the homogenization of the temperature field and the concentration field during the solidification process, improves the graphite nucleation rate, and on the other hand, cooperates with the anisotropic surface tension to cause the splitting and refinement of graphite during the growth process, and finally realizes the refinement of the graphite size in the cast ingot.

[0018] Further, the rotating speed of the bottom centrifugal disc in step (4) is 7.5-22.5 rpm, and the rotating speed of the centrifugal barrel is 10-30 rpm. The centrifugal barrel and the bottom centrifugal disc are operated at a rotating speed ratio of 1:0.75 for 20 minutes, and then the ingot is taken out.

[0019] Further, the rolling in step (5) is specifically as follows:

[0020] Process 1: The ingot is cut into a slab, heated to 1200℃ for 0.8-1.2 hours for homogenization treatment, and the initial rolling temperature and the final rolling temperature are controlled. First, multi-pass rough rolling is performed, and the appropriate reduction and rolling temperature are maintained in each pass;

[0021] Process 2: Multi-pass finish rolling is performed, and the appropriate reduction and rolling temperature are maintained in each pass, and the final total reduction is controlled, i.e. the required rolling plate is obtained;

[0022] Process 3: After rolling is completed, the steel plate is immediately placed in a heat treatment furnace of a certain temperature prepared in advance, the power of the heat treatment furnace is turned off, and the vibration reduction steel rolling plate is cooled to room temperature in the furnace, and then taken out;

[0023] Further, the rolling pass of rough rolling in process 1 is 3-5, and the reduction per pass is 5-15 mm; the rough rolling cutoff temperature is 800℃.

[0024] Further, the finish rolling pass in process 2 is 3-5, the reduction per pass is 1-5 mm, the initial finish rolling temperature is 780℃, and the finish rolling cutoff temperature is 740℃.

[0025] Further, the heat treatment holding time in step (6) is 1-2 hours, and the heat treatment temperature is 750-780℃.

[0026] The application also provides a melting and casting device for preparing the high-carbon damping and vibration reduction steel by the method as described above, which has been described in the applicant's prior application CN110538977A. The schematic diagram of the principle of the device is shown in Figure 1 The device is composed of a melting system, a pouring system, a bottom centrifugal disc, a coupling shaft, and a centrifugal barrel. The mold is arranged in the centrifugal barrel, the centrifugal barrel is connected with the bottom centrifugal disc through the coupling shaft, the bottom centrifugal disc rotates under the control of the motor, and at the same time drives the centrifugal barrel to rotate through the coupling shaft, and the rotating speed ratio of the bottom centrifugal disc and the centrifugal barrel is adjusted by replacing the coupling shaft gear to realize the transmission ratio.

[0027] The application adopts composite shear flow casting-rolling-heat treatment to prepare high-carbon damping and vibration reduction steel, and innovatively adopts composite shear flow casting technology. The prepared vibration reduction steel can greatly shorten the heat treatment time while ensuring excellent mechanical properties and vibration reduction performance.

[0028] The beneficial effects of the present application are that after the melt is injected into the mold, the composite shear flow causes the uniform mixing of each element in the melt, and at the same time promotes the uniform distribution of the temperature field in the macro region. In this way, the melt can be nucleated in a large amount under a certain degree of supercooling, and grain refinement is achieved. Therefore, through composite shear flow casting, the graphite phase in the high-carbon damping steel ingot is fine and dispersedly distributed, which is important for shortening the subsequent heat treatment time and obtaining excellent performance. The high-carbon damping steel manufactured by the composite shear flow casting method has the advantages of low cost, short heat treatment period, excellent performance, etc. The process is simple and easy to implement, and can be mass-produced. BRIEF DESCRIPTION OF DRAWINGS

[0029] Other features, details and advantages of the present application will be more clearly and completely understood through the following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings.

[0030] Figure 1 Schematic diagram of the principle of the composite shear flow equipment.

[0031] Figure 2 Scanning electron microscope picture of the as-cast microstructure of the high-carbon damping steel under the action of the composite shear flow in the example.

[0032] Figure 3 Scanning electron microscope picture of the as-cast microstructure of the high-carbon damping steel under the action of the composite shear flow in the example.

[0033] Figure 4 Comparison chart of the tensile engineering stress-strain curves of the high-carbon damping steel under the action of the composite shear flow casting and traditional casting in the example.

[0034] Figure 5 Comparison of the damping performance of the high-carbon damping steel under the action of the composite shear flow casting and traditional casting in the example. DETAILED DESCRIPTION

[0035] The present application will be described in detail below through exemplary embodiments. It should be noted that those skilled in the art can easily understand that the following embodiments are only some exemplary embodiments of the method of the present application given by way of example, and do not mean any limitation on the present application.

[0036] EMBODIMENT

[0037] Step one: a high-carbon damping steel, the main elements in the steel by mass percent content: C: 1.2%, Si: 1.6%, Mn: 0.210%, Ni: 2.2%, Al: 0.260%, the balance: Fe. According to the above chemical composition of ingredients, the raw materials are put into the crucible of the smelting system, the casting is embedded in the centrifugal barrel, the refractory insulation material is filled between the casting and the centrifugal barrel, the casting is preheated at 200℃ for more than 2h. The vacuum induction furnace is used for smelting, the raw materials in the crucible are heated to more than 1500℃ to melt, after melting, the composite shear flow casting is carried out, that is, the alloy melt is poured into the casting, the motor is started to drive the bottom centrifugal disc, the centrifugal barrel is driven by the bottom centrifugal disc, the centrifugal barrel and the bottom centrifugal disc move at a speed ratio of 1:0.75 for 20 minutes, and the cast ingot is taken out after the alloy is completely solidified. The centrifugal barrel rotates at 20 revolutions per minute, and the bottom centrifugal disc rotates at 15 revolutions per minute.

[0038] Step two: the prepared cast ingot is uniformly homogenized at high temperature and then hot-rolled, specifically as follows: process 1: the cast ingot is cut into a slab with a thickness of 60mm, heated to 1200℃ and kept for 2h, the initial rolling temperature is 1080℃, four passes of rough rolling are carried out, and the downward displacement amounts are 15, 10, 7 and 5mm respectively, and the rolling temperatures are 1080℃, 1010℃, 950℃ and 800℃ respectively, and finally a steel plate with a thickness of 23mm is rolled; process 2: four passes of finish rolling are carried out, and the downward displacement amounts are 4, 3, 3 and 2mm respectively, and the rolling temperatures are 780℃, 770℃, 760℃ and 740℃ respectively, and finally a steel plate with a thickness of 11mm is rolled; process 3: after rolling, the rolled plate is immediately put into a pre-prepared annealing furnace at 390℃ for cooling to room temperature and then taken out.

[0039] Step three: the rolled plate subjected to composite shear flow casting and hot rolling is treated at 750℃ for 1h and then subjected to furnace cooling treatment to graphitize the rolled plate, that is, the high-carbon damping steel plate is obtained.

[0040] Comparative example 1

[0041] A high-carbon damping steel plate is prepared by using a traditional gravity casting method.

[0042] Step one: the same chemical composition as in the example is used for batching, and the same process is used for smelting. After melting, the composite shear flow casting is not carried out, and the alloy melt is directly poured into the casting until it is completely solidified.

[0043] Step two: the hot rolling process is the same as in the example.

[0044] Step three: the rolled plate subjected to traditional casting and hot rolling is treated at 750℃ for 4h and 8h respectively.

[0045] Figure 2 、 Figure 3The scanning photos of the as-cast microstructure of the damping steel under the heat preservation for 8h by the composite shear flow casting and the traditional casting, respectively, are ferrite + pearlite + graphite, and it can be obviously seen that the graphite in the damping steel prepared by the composite shear flow casting is more fine and uniformly dispersed.

[0046] Table 1

[0047]

[0048] The mechanical properties of the high-carbon damping steel plate prepared in the example and the comparative example 1 are shown in Table 1, and it can be seen that the tensile strength and yield strength of the example are obviously improved. The stress-strain curve is shown in Figure 4 It can be seen that the plasticity is similar, the strength is improved, the heat treatment time of the damping steel prepared by the composite shear flow casting is greatly shortened, and the production period and production cost of the steel plate can be significantly saved.

[0049] The damping performance of the heat-treated steel plate is tested by the DMA Q800 experimental instrument. Figure 5 The damping loss factor Q -1 of the high-carbon damping steel prepared by different casting processes under different heat treatment processes is shown in Table 1. It can be seen that under the same heat treatment temperature, the damping steel prepared by the composite shear flow casting only needs 1h of heat treatment time, and its damping performance (Q -1 = 0.0218) is better than that of the damping steel prepared by the traditional casting under the heat preservation for 4h or 8h (Q -1 = 0.0165, 0.0194), respectively.

[0050] In summary, under the condition of ensuring the mechanical properties, the heat treatment time of the high-carbon damping steel prepared by the composite shear flow technology is greatly shortened, and its damping performance is better than that of the high-carbon damping steel prepared by the traditional casting.

[0051] Comparative example 2

[0052] Step one: according to the same chemical composition of the example, the alloy is prepared and melted by the same process. After melting, the composite shear flow casting is carried out, that is, the alloy melt is poured into the mold, the motor is started to drive the bottom centrifugal disc, the centrifugal barrel is driven, the centrifugal barrel and the bottom centrifugal disc are moved at different speeds and speed ratios for 20 minutes, and then the ingot is taken out after the alloy is completely solidified.

[0053] Step two hot rolling and step three heat preservation process are the same as the example.

[0054] The speed and speed ratio setting mode in step one and the damping performance are shown in Table 2.

[0055] Table 2

[0056]

[0057] From the data in Table 2, it can be seen that the damping performance of the high-carbon damping and vibration reduction steel prepared by the composite shear flow technology decreases with the change of the rotation speed ratio of the centrifugal barrel and the bottom centrifugal disc, but is still superior to that of the high-carbon damping and vibration reduction steel prepared by traditional casting.

[0058] The above is only the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing high-carbon damping vibration-damping steel, characterized in that, A composite casting method combining vacuum induction melting and centrifugal casting, utilizing composite shear flow technology, and combined with subsequent controlled rolling and cooling and heat treatment technologies, shortens the heat treatment time of high-carbon damping vibration reduction steel, including the following steps: (1) Prepare the raw materials required for smelting. The chemical composition of the high carbon damping vibration reduction steel by mass percentage is: C≥1.2%, Si:1.5%-1.7%, Mn:0.20%-0.22%, Ni:2.15%-2.25%, Al:0.25%-0.27%, balance: Fe; (2) Place the raw materials into the crucible of the melting system, embed the mold into the centrifuge, fill the space between the mold and the centrifuge with refractory insulation material, and preheat the mold. (3) The raw materials in the crucible are heated and melted by induction melting process and kept at a certain temperature. After the temperature is maintained, the alloy melt is poured into the mold. (4) Turn on the motor to drive the bottom centrifugal disc, which will drive the centrifugal barrel. The centrifugal barrel and the bottom centrifugal disc will move at the set speed ratio until the alloy is completely solidified and the ingot is removed. In step (4), the bottom centrifugal disc rotates in the opposite direction to the centrifugal barrel. The bottom centrifugal disc rotates counterclockwise and the centrifugal barrel rotates clockwise, forming the rotation and revolution of the melt. During the solidification process, a composite shear flow is generated inside the alloy melt. The composite shear flow promotes the homogenization of the temperature field and concentration field during solidification, increases the graphite nucleation rate, and works synergistically with the anisotropic surface tension to cause the graphite to split and refine during growth, ultimately achieving the refinement of the graphite size in the ingot. In step (4), the centrifuge tank and the bottom centrifuge plate rotate at a speed ratio of 1:0.75 for 20 minutes, after which the ingot is removed; (5) After the ingot is homogenized at high temperature, it is rolled by controlling the temperature of the rolling process; (6) After isothermal heat treatment, the rolled plate is furnace cooled to graphitize it, thus obtaining the high carbon damping steel.

2. The method for preparing high-carbon damping vibration-damping steel as described in claim 1, characterized in that, The specific rolling steps described in step (5) are as follows: Process 1: Cut the ingot into slabs, heat to 1200℃ and hold for 0.8-1.2 hours for homogenization treatment, control the initial rolling temperature and the final rolling temperature, first perform multiple rough rolling passes, and maintain appropriate pressure and rolling temperature in each rolling pass; Step 2: Perform multi-pass finishing rolling, maintaining appropriate pressure and rolling temperature in each rolling pass, and controlling the final total pressure to obtain the required rolled plate; Step 3: After rolling, the steel plate is immediately placed in a pre-prepared heat treatment furnace at a certain temperature. The power to the heat treatment furnace is turned off, and the vibration-damping steel plate is cooled to room temperature in the furnace before being taken out.

3. The method for preparing high-carbon damping vibration-damping steel as described in claim 2, characterized in that, The roughing process described in step 1 has 3-5 rolling passes, with a reduction of 5-15 mm per pass; the roughing cutoff temperature is 800℃.

4. The method for preparing high-carbon damping vibration-damping steel as described in claim 2, characterized in that, The finishing rolling process in step 2 consists of 3-5 passes, with a reduction of 1-5 mm per pass. The initial finishing rolling temperature is 780℃, and the finishing rolling cutoff temperature is 740℃.

5. The method for preparing high-carbon damping vibration-damping steel as described in claim 1, characterized in that, In step (6), the heat treatment holding time is 1-2 hours and the heat treatment temperature is 750-780℃.

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