High-anti-cracking spherical flat steel and preparation method thereof

Abstract

The present application relates to the technical field of ball flat steel, in particular to a high-anti-cracking ball flat steel and a preparation method thereof.The present application comprises the following steps: S1: after raw materials are subjected to converter smelting, LF refining and VD refining, continuous casting is performed to obtain continuous casting billets; S2: after the continuous casting billets are heated and rolled, intermediate billets are obtained; the surface of the intermediate billets is degreased, carburizing treatment is performed, and then quenching and tempering treatment are performed to obtain ball flat steel; S3: graphene oxide and modified silicon dioxide are ultrasonically dispersed in deionized water, water-based epoxy resin, a curing agent, an adhesion promoter, a leveling agent and a defoaming agent are added and uniformly mixed to obtain an anti-permeation composite coating; the anti-permeation composite coating is coated on the surface of the ball flat steel, and after drying, an anti-permeation composite coating is formed to obtain the high-anti-cracking ball flat steel, which not only has excellent mechanical properties, but also has excellent hydrophobic properties and corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bulb flat steel, in particular to a high-anti-cracking bulb flat steel and a preparation method thereof. BACKGROUND

[0002] As one of the key materials in shipbuilding, bulb flat steel is widely used in ship body framework, deck beam, bulkhead and other parts. It not only bears various static and dynamic loads during ship operation, but also needs to resist seawater corrosion and low-temperature toughness challenges in marine environment. Therefore, improving the anti-cracking performance of bulb flat steel is of great significance to improve the overall safety and service life of ships.

[0003] However, the bulb flat steel in the prior art is usually made of conventional steel materials, although it has certain strength, but under the action of stress concentration and temperature change and other factors, cracks are easy to appear. In addition, the traditional surface treatment methods of bulb flat steel, such as spraying and galvanizing, although can provide certain anti-corrosion effect, but when exposed to harsh environments (such as humidity, salt spray, etc.) for a long time, the protective layer may peel off and crack, causing the substrate to be exposed and accelerate corrosion.

[0004] Therefore, we propose a high-anti-cracking bulb flat steel and a preparation method thereof. SUMMARY

[0005] The purpose of the present application is to provide a high-anti-cracking bulb flat steel and a preparation method thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A preparation method of a high-anti-cracking bulb flat steel, comprising the following steps:

[0008] Step S1: After the raw materials are subjected to converter smelting, LF refining and VD refining, continuous casting is performed to obtain a continuous casting billet;

[0009] Step S2: After the continuous casting billet is heated and rolled, an intermediate billet is obtained; the surface of the intermediate billet is degreased, carburizing treatment is performed, and then quenching and tempering treatment are performed to obtain a bulb flat steel;

[0010] Step S3: The graphene oxide and modified silicon dioxide are ultrasonically dispersed in deionized water, and the water-based epoxy resin, curing agent, adhesion promoter, leveling agent and defoaming agent are mixed uniformly to obtain an anti-permeation composite coating; the anti-permeation composite coating is coated on the surface of the bulb flat steel, and after drying, an anti-permeation composite coating is formed to obtain a high-anti-cracking bulb flat steel.

[0011] Further, the raw material comprises the following weight percentages of elements: C: 0.08-0.12%, Si: 0.15-0.35%, Mn: 0.5-1.0%, Cr: 0.80-1.0%, Mo: 0.05-0.08%, V: 0.06-0.12%, N: 0.015-0.020%, Nb: 0.04-0.06%, Als: 0.015-0.030%, Ti: 0.01-0.02%, P≤0.02%, S≤0.02%, and the balance being Fe.

[0012] Further, in the converter smelting process, the tapping temperature is 1650-1750℃; the temperature of LF refining is 1500-1600℃.

[0013] Further, in the VD refining, argon bottom blowing and vacuum treatment are performed, the vacuum degree is 50-80Pa, and the holding time is 15-25min.

[0014] Further, the process conditions of continuous casting are as follows: the temperature of continuous casting liquid steel is 1500-1540℃, the superheat of tundish is 20-30℃, and the casting speed is 1.4-1.8m / min.

[0015] Further, in the step S2, the process conditions of heating are as follows: the heating temperature is 1150-1200℃, and the holding time is 2-4h.

[0016] Further, in the step S2, the rolling is specifically two-stage rolling, the rolling temperature of the first stage is 1050-1100℃, the rolling deformation is 40-50%, the rolling temperature of the second stage is 850-950℃, the rolling deformation is 30-50%, and after rolling, water cooling is performed at 2-5℃ / s to 550-600℃, and then air cooling is performed to room temperature.

[0017] Further, in the step S2, the process conditions of carburizing treatment are as follows: a mixed gas composed of nitrogen and methanol in a ratio of (1-1.5)m 3 :1L is used as the carburizing agent, dropwise carburizing is adopted, the holding temperature is 900-950℃, the holding time is 1-2h, and the thickness of the carburized layer is 0.2-0.5mm.

[0018] Further, the process conditions of tempering are as follows: the tempering temperature is 600-650℃, and the tempering time is 1-2h.

[0019] Further, the anti-permeation composite coating comprises the following weight components: water-based epoxy resin 50-70 parts, graphene oxide 5-10 parts, modified silicon dioxide 10-15 parts, deionized water 30-50 parts, curing agent 10-15 parts, adhesion promoter 0.5-1.0 parts, leveling agent 0.1-0.3 parts, and defoaming agent 0.1-0.3 parts.

[0020] Further, the preparation method of the modified silica is as follows:

[0021] Step (1): dispersing silica in a mixed solution of anhydrous ethanol and deionized water, adding 3-chloropropyl triethoxysilane and mixing uniformly, reacting at 60-70°C for 5-7h, and obtaining chlorinated silica after centrifugation, washing and drying;

[0022] Step (2): dispersing chlorinated silica in a mixed solution of anhydrous ethanol and deionized water, adding branched polyethyleneimine and triethylamine, and reacting at 30-40°C for 12-24h, and obtaining amino-containing silica after filtration, washing and drying;

[0023] Step (3): mixing amino-containing silica, anhydrous ethanol and deionized water uniformly, adding epoxy-terminated fluorine-containing polyether, reacting for 4-6h, then adding dodecenyl succinic anhydride ethanol solution, adjusting the pH of the system to 8.4-8.6, and reacting at 40-50°C for 5-7h, and obtaining modified silica after filtration, washing and drying.

[0024] Further, in step (1), the mass ratio of silica, anhydrous ethanol, deionized water and 3-chloropropyl triethoxysilane is 1:(15-20):(3-5):(2-4).

[0025] Further, in step (2), the mass ratio of chlorinated silica, anhydrous ethanol, deionized water and branched polyethyleneimine is 1:(15-20):(3-5):(3-5).

[0026] Further, in step (2), the mass of triethylamine is 3-5% of the mass of chlorinated silica.

[0027] Further, the mass ratio of amino-containing silica, anhydrous ethanol, deionized water and epoxy-terminated fluorine-containing polyether is 1:(15-20):(3-5):(1-2).

[0028] Further, the preparation steps of the epoxy-terminated fluorine-containing polyether are as follows: mixing hexafluorobisphenol A, trimethylolpropane triglycidyl ether and tetrabutylammonium bromide uniformly under nitrogen protection, and reacting at 100-110°C for 5-6h, and obtaining epoxy-terminated fluorine-containing polyether after filtration, washing and drying.

[0029] In the above technical scheme, the branched polyether with terminal epoxy group is generated by taking hexafluorobisphenol A and trimethylolpropane triglycidyl ether as raw materials and reacting under the catalysis of tetrabutylammonium bromide, the fluorine element is introduced into the polyether, the water resistance of the material can be effectively improved, and the introduction of the terminal epoxy group enhances the crosslinking density of the polymer, the crosslinking structure can improve the mechanical strength and durability of the coating, slow down the penetration of moisture and corrosion medium, and realize the double improvement of hydrophobic performance and corrosion resistance.

[0030] Further, the mass ratio of the hexafluorobisphenol A, the trimethylolpropane triglycidyl ether and the tetrabutylammonium bromide is 1: (3.0-3.5): (0.03-0.05).

[0031] Further, the concentration of the dodecenyl succinic anhydride ethanol solution is 10-12 wt%, and the amount is 4-6 times of the mass of the terminal epoxy group-containing fluorine-containing polyether.

[0032] Further, the thickness of the anti-permeation composite coating is 100-200 mu m.

[0033] Compared with the prior art, the beneficial effects of the present application are:

[0034] 1. The high anti-cracking ball flat steel and the preparation method thereof, taking 3-chloropropyl triethoxysilane (CPTES) as an end group modifier, chlorinated silicon dioxide is prepared, that is, chlorinated silicon dioxide; then branched polyethylene imine is introduced as a corrosion inhibitor, the branched polyethylene imine is used to modify the chlorinated silicon dioxide, so that a large number of amino groups are grafted on the surface of the silicon dioxide, and amino-containing silicon dioxide is obtained; finally, the fluorine element is introduced by reacting the amino-containing silicon dioxide with the epoxy group in the terminal epoxy group-containing fluorine-containing polyether, and a hydroxyl group is generated at the same time, then dodecenyl succinic anhydride is used as a hydrophobic modifier to perform esterification reaction, a hydrophobic long-chain structure is introduced, and the hydrophobicity of the silicon dioxide is further improved, the modified silicon dioxide can form a more dense hydrophobic layer in the epoxy resin coating, so as to improve the water resistance and anti-pollution ability of the coating, and reduce the penetration of moisture, oil stains or other external substances.

[0035] 2. The high anti-cracking ball flat steel and the preparation method thereof, by controlling the rolling temperature and the cooling speed, the grain structure is refined, the strength and toughness of the steel are improved, and the generation of cracks is reduced; by performing carburizing treatment on the intermediate blank, the hardness and wear resistance of the surface are improved, after quenching and tempering treatment, the surface has high hardness, wear resistance and fatigue resistance, while the core still maintains sufficient strength and toughness, avoiding cracks or damage caused by long-term use, and then coating the anti-permeation composite coating, the corrosion resistance and anti-permeability of the ball flat steel can be further improved. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] In the present embodiment, the graphene oxide has a model number of DN-20DY, an average thickness of 1-3 nm, a diameter of 4-7 μm, and 2-5 layers, and is from Zhejiang Zhiti Nano Micro New Material Co., Ltd.; the silicon dioxide has a product number of HL-260 and is from Hubei HuiFu Nano Material Co., Ltd.; the branched polyethylene imine has a model number of 408727 and is from Merck; the water-based epoxy resin has a brand of American Dow DER-916; the curing agent has a model number of polyamide 650; the adhesion promoter has a model number of BYK-4511 from BYK; the leveling agent has a model number of KYC-615 from Kaimin; and the defoaming agent has a model number of BYK-028 from BYK.

[0038] In the following examples and comparative examples, 1 part is equal to 10 g.

[0039] Example 1: A preparation method of a high-anti-cracking ball flat steel, comprising the following processes:

[0040] Step S1: After raw materials are subjected to converter smelting (tapping temperature of 1650℃), LF refining (1500℃) and VD refining (bottom argon blowing and vacuum extraction treatment are performed, vacuum degree of 50 Pa, and holding time of 15 min), continuous casting (continuous casting steel temperature of 1500℃, tundish superheat of 20℃, and casting blank drawing speed of 1.4 m / min) is performed to obtain a continuous casting blank;

[0041] Step S2: After the continuous casting blank is heated (heating temperature of 1150℃, and holding time of 2 h) and rolled (two-stage rolling, first-stage rolling temperature of 1050℃, and rolling deformation of 40%; second-stage rolling temperature of 850℃, and rolling deformation of 30%, and then water-cooled to 550℃ at a speed of 2℃ / s, and then air-cooled to room temperature), an intermediate blank is obtained; the surface of the intermediate blank is degreased, subjected to carburizing treatment (a mixed gas composed of 1 L of nitrogen and 1 L of methanol is used as a carburizing agent, dropwise carburizing is adopted, holding temperature is 900℃, and holding time is 1 h), quenched to room temperature, and subjected to tempering treatment (tempering temperature is 600℃, and tempering time is 1 h) to obtain a ball flat steel. 3

[0042] ​Step S3: 5 parts of graphene oxide, 10 parts of modified silica were ultrasonically dispersed in 30 parts of deionized water, 50 parts of water-based epoxy resin, 10 parts of curing agent, 0.5 parts of adhesion promoter, 0.1 parts of leveling agent and 0.1 parts of defoaming agent were added and uniformly mixed to obtain an anti-permeable composite coating; the anti-permeable composite coating was coated on the surface of the ball flat steel, and after drying, an anti-permeable composite coating was formed to obtain a high anti-cracking ball flat steel;

[0043] The raw material includes the following weight percentages of elements: C: 0.08%, Si: 0.15%, Mn: 0.5%, Cr: 0.8%, Mo: 0.05%, V: 0.06%, N: 0.015%, Nb: 0.04%, Als: 0.015%, Ti: 0.01%, P≤0.02%, S≤0.02%, and the balance is Fe;

[0044] The preparation method of the modified silica is as follows:

[0045] Step (1): 10 parts of silica were ultrasonically dispersed in a mixed solution of 150 parts of anhydrous ethanol and 30 parts of deionized water, 20 parts of 3-chloropropyl triethoxysilane were added and uniformly mixed, and the mixture was reacted at 60°C for 5h, and then centrifuged, washed and dried to obtain chlorinated silica;

[0046] Step (2): 10 parts of chlorinated silica were ultrasonically dispersed in a mixed solution of 150 parts of anhydrous ethanol and 30 parts of deionized water, 30 parts of branched polyethyleneimine and 0.3 parts of triethylamine were added and reacted at 30°C for 24h, and then filtered, washed and dried to obtain amino-containing silica;

[0047] Step (3): 10 parts of amino-containing silica, 150 parts of anhydrous ethanol and 30 parts of deionized water were uniformly mixed, 10 parts of epoxy-terminated fluorine-containing polyether were added and reacted for 4h, then 40 parts of 10wt% dodecenyl succinic anhydride ethanol solution was added, the pH of the system was adjusted to 8.4, and the mixture was reacted at 40°C for 5h, and then filtered, washed and dried to obtain modified silica;

[0048] The preparation steps of the epoxy-terminated fluorine-containing polyether are as follows: 10 parts of hexafluorobisphenol A, 30 parts of trimethylolpropane triglycidyl ether and 0.3 parts of tetrabutylammonium bromide were uniformly mixed under nitrogen protection, and the mixture was reacted at 100°C for 5h, and then filtered, washed and dried to obtain epoxy-terminated fluorine-containing polyether.

[0049] Example 2: A preparation method of a high anti-cracking ball flat steel, comprising the following processes:

[0050] Step S1: After raw materials are subjected to converter smelting (tapping temperature is 1700℃), LF refining (1550℃) and VD refining (bottom argon blowing and vacuum treatment are performed, vacuum degree is 60 Pa, and holding time is 20 min), continuous casting (continuous casting temperature is 1530℃, tundish superheat is 25℃, and casting speed is 1.6 m / min) is performed, so as to obtain a continuous casting billet;

[0051] Step S2: After the continuous casting billet is subjected to heating (heating temperature is 1180℃, and holding time is 3 h) and rolling (two-stage rolling, the rolling temperature of the first stage is 1080℃, the rolling deformation is 45%, the rolling temperature of the second stage is 900℃, the rolling deformation is 40%, and after rolling, water cooling is performed at 4℃ / s to 580℃, and then air cooling is performed to room temperature), a middle billet is obtained; the surface of the middle billet is degreased, carburizing treatment is performed (a mixed gas composed of nitrogen and methanol in a mass ratio of 1.2:1 is used as a carburizing agent, dropwise carburizing is adopted, the holding temperature is 920℃, and the holding time is 1.5 h), quenching to room temperature and tempering treatment (the tempering temperature is 620℃, and the tempering time is 1.5 h) are performed, so as to obtain a ball flat steel; 3 :1L group as a carburizing agent, dropwise carburizing is adopted, the holding temperature is 920℃, and the holding time is 1.5 h), quenching to room temperature and tempering treatment (the tempering temperature is 620℃, and the tempering time is 1.5 h) are performed, so as to obtain a ball flat steel;

[0052] Step S3: 8 parts of graphene oxide, 12 parts of modified silicon dioxide are ultrasonically dispersed in 40 parts of deionized water, 60 parts of water-based epoxy resin, 12 parts of curing agent, 0.8 parts of adhesion promoter, 0.2 parts of leveling agent and 0.2 parts of defoaming agent are added and uniformly mixed to obtain an anti-permeation composite coating; the anti-permeation composite coating is coated on the surface of the ball flat steel, dried to form an anti-permeation composite coating layer, and a high-anti-cracking ball flat steel is obtained;

[0053] The raw material includes the following elements in percentage by weight: C: 0.1%, Si: 0.2%, Mn: 0.8%, Cr: 0.9%, Mo: 0.07%, V: 0.1%, N: 0.018%, Nb: 0.05%, Als: 0.02%, Ti: 0.015%, P≤0.02%, S≤0.02%, and the balance is Fe;

[0054] The preparation method of the modified silicon dioxide is as follows:

[0055] Step (1): 12 parts of silicon dioxide are ultrasonically dispersed in a mixed solution of 210 parts of anhydrous ethanol and 48 parts of deionized water, 36 parts of 3-chloropropyl triethoxysilane are added and uniformly mixed, and the mixture is reacted at 65℃ for 6 h; after centrifugation, washing and drying, chlorinated silicon dioxide is obtained;

[0056] Step (2): 12 parts of chlorinated silicon dioxide are ultrasonically dispersed in a mixed solution of 210 parts of anhydrous ethanol and 48 parts of deionized water, 48 parts of branched polyethyleneimine and 0.5 parts of triethylamine are added, and the mixture is reacted at 35℃ for 18 h; after filtration, washing and drying, amino-containing silicon dioxide is obtained;

[0057] Step (3): 12 parts of amino-containing silica, 210 parts of anhydrous ethanol and 48 parts of deionized water were mixed uniformly, 18 parts of epoxy-terminated fluorine-containing polyether was added, and the reaction was carried out for 5 h, then 90 parts of 11 wt% dodecenyl succinic anhydride ethanol solution was added, the pH of the system was adjusted to 8.5, and the reaction was carried out at 45℃ for 6 h. After filtration, washing and drying, the modified silica was obtained;

[0058] The preparation steps of the epoxy-terminated fluorine-containing polyether are as follows: under nitrogen protection, 18 parts of hexafluorobisphenol A, 57.6 parts of trimethylolpropane triglycidyl ether and 0.72 parts of tetrabutylammonium bromide were mixed uniformly, and the reaction was carried out at 105℃ for 5.5 h. After filtration, washing and drying, the epoxy-terminated fluorine-containing polyether was obtained.

[0059] Example 3: A preparation method of high anti-cracking ball flat steel, comprising the following processes:

[0060] Step S1: After the raw materials are subjected to converter smelting (tapping temperature is 1750℃), LF refining (1600℃) and VD refining (bottom blowing argon and vacuum treatment are carried out, vacuum degree is 50-80 Pa, and holding time is 15-25 min), continuous casting (continuous casting steel temperature is 1500-1540℃, tundish overheat is 20-30℃, and casting blank drawing speed is 1.4-1.8 m / min) is carried out, and a continuous casting blank is obtained;

[0061] Step S2: After the continuous casting blank is subjected to heating (heating temperature is 1150-1200℃, and holding time is 2-4 h), rolling (two-stage rolling, the rolling temperature of the first stage is 1050-1100℃, and the rolling deformation is 40-50%; the rolling temperature of the second stage is 850-950℃, and the rolling deformation is 30-50%, and after rolling, water cooling is carried out at 2-5℃ / s to 550-600℃, and then air cooling is carried out to room temperature), the surface of the intermediate blank is degreased, carburizing treatment is carried out (a mixed gas composed of nitrogen and methanol in a proportion of (1-1.5) m3:1 L is used as a carburizing agent, drop injection type carburizing is adopted, the holding temperature is 900-950℃, and the holding time is 1-2 h), and then quenching to room temperature and tempering treatment (the tempering temperature is 600-650℃, and the tempering time is 1-2 h) are carried out, and a ball flat steel is obtained;

[0062] Step S3: 5-10 parts of graphene oxide, 10-15 parts of modified silica are ultrasonically dispersed in 30-50 parts of deionized water, 50-70 parts of water-based epoxy resin, 10-15 parts of curing agent, 0.5-1.0 parts of adhesion promoter, 0.1-0.3 parts of leveling agent and 0.1-0.3 parts of defoaming agent are uniformly mixed, and an anti-permeation composite coating is obtained. The anti-permeation composite coating is coated on the surface of the ball flat steel, dried, and an anti-permeation composite coating is formed, and a high anti-cracking ball flat steel is obtained;

[0063] The raw material includes the following weight percentages of elements: C: 0.08-0.12%, Si: 0.15-0.35%, Mn: 0.5-1.0%, Cr: 0.80-1.0%, Mo: 0.05-0.08%, V: 0.06-0.12%, N: 0.015-0.020%, Nb: 0.04-0.06%, Als: 0.015-0.030%, Ti: 0.01-0.02%, P≤0.02%, S≤0.02%, and the balance being Fe;

[0064] The preparation method of the modified silica is as follows:

[0065] Step (1): 10-15 parts of silica are ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, 3-chloropropyltriethoxysilane is added and uniformly mixed, and the mixture is reacted at 60-70℃ for 5-7h, and then centrifuged, washed, and dried to obtain chlorinated silica;

[0066] Step (2): The chlorinated silica is ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, branched polyethyleneimine and triethylamine are added, and the mixture is reacted at 30-40℃ for 12-24h, and then filtered, washed, and dried to obtain amino-containing silica;

[0067] Step (3): The amino-containing silica, anhydrous ethanol, and deionized water are uniformly mixed, an epoxy-terminated fluorine-containing polyether is added, and the mixture is reacted for 4-6h, then dodecenyl succinic anhydride ethanol solution is added, the pH of the system is adjusted to 8.4-8.6, and the mixture is reacted at 40-50℃ for 5-7h, and then filtered, washed, and dried to obtain modified silica;

[0068] The preparation steps of the epoxy-terminated fluorine-containing polyether are as follows: under nitrogen protection, hexafluorobisphenol A, trimethylolpropane triglycidyl ether, and tetrabutylammonium bromide are uniformly mixed, and the mixture is reacted at 100-110℃ for 5-6h, and then filtered, washed, and dried to obtain the epoxy-terminated fluorine-containing polyether.

[0069] Comparative Example 1: A preparation method of a high-anti-cracking spherical flat steel includes the following processes:

[0070] Step S1: After the raw material is subjected to converter smelting (tapping temperature of 1700℃), LF refining (1550℃), and VD refining (bottom argon blowing and vacuum treatment are performed, the vacuum degree is 60Pa, and the holding time is 20min), continuous casting (continuous casting steel water temperature of 1530℃, tundish superheat of 25℃, and casting blank pulling speed of 1.6m / min) is performed to obtain a continuous casting blank;

[0071] Step S2: after heating (heating temperature 1180℃, holding time 3h), rolling (two-stage rolling, the rolling temperature of the first stage is 1080℃, the rolling deformation is 45%; the rolling temperature of the second stage is 900℃, the rolling deformation is 40%, and after rolling, water cooling is carried out at 4℃ / s to 580℃, and then air cooling is carried out to room temperature), the continuous casting billet is obtained; the surface of the intermediate billet is degreased, carburizing treatment is carried out (a mixed gas composed of nitrogen and methanol in a mass ratio of 1.2:1 is used as a carburizing agent, drop injection carburizing is adopted, the holding temperature is 920℃, the holding time is 1.5h), and then quenching to room temperature and tempering treatment (the tempering temperature is 620℃, the tempering time is 1.5h) are carried out, so that the ball flat steel is obtained; 3 :1L is used as a carburizing agent, drop injection carburizing is adopted, the holding temperature is 920℃, the holding time is 1.5h), and then quenching to room temperature and tempering treatment (the tempering temperature is 620℃, the tempering time is 1.5h) are carried out, so that the ball flat steel is obtained;

[0072] Step S3: 8 parts of graphene oxide, 12 parts of silicon dioxide are ultrasonically dispersed in 40 parts of deionized water, 60 parts of water-based epoxy resin, 12 parts of curing agent, 0.8 parts of adhesion promoter, 0.2 parts of leveling agent and 0.2 parts of defoaming agent are added and uniformly mixed to obtain a anti-permeation composite coating; the anti-permeation composite coating is coated on the surface of the ball flat steel, and after drying, an anti-permeation composite coating layer is formed to obtain a high anti-cracking ball flat steel;

[0073] Compared with Example 2, the modified silicon dioxide in Comparative Example 1 is replaced by the same mass of silicon dioxide, and the other steps are the same as those in Example 2.

[0074] Comparative Example 2: a preparation method of a high anti-cracking ball flat steel, comprising the following processes:

[0075] The preparation method of the modified silicon dioxide is as follows:

[0076] Step (1): 12 parts of silicon dioxide are ultrasonically dispersed in a mixed solution of 210 parts of anhydrous ethanol and 48 parts of deionized water, 36 parts of 3-chloropropyl triethoxysilane are added and uniformly mixed, and reaction is carried out at 65℃ for 6h; after centrifugation, washing and drying, chlorinated silicon dioxide is obtained;

[0077] Step (2): 12 parts of chlorinated silicon dioxide are ultrasonically dispersed in a mixed solution of 210 parts of anhydrous ethanol and 48 parts of deionized water, 48 parts of branched polyethyleneimine and 0.5 parts of triethylamine are added, and reaction is carried out at 35℃ for 18h; after filtration, washing and drying, amino-containing silicon dioxide is obtained;

[0078] Step (3): 12 parts of amino-containing silicon dioxide, 210 parts of anhydrous ethanol and 48 parts of deionized water are uniformly mixed, 90 parts of 11wt% dodecenyl succinic anhydride ethanol solution is added, the pH of the system is adjusted to 8.5, and reaction is carried out at 45℃ for 6h; after filtration, washing and drying, modified silicon dioxide is obtained;

[0079] Compared with Example 2, Comparative Example 2 does not add an epoxy-terminated fluorine-containing polyether, and the other steps are the same as those in Example 2.

[0080] Preparation method of a high anti-cracking ball flat steel, comprising the following processes:

[0081] Step S1: After raw materials are subjected to converter smelting (tapping temperature is 1700℃), LF refining (1550℃) and VD refining (bottom argon blowing and vacuum extraction treatment are performed, vacuum degree is 60Pa, and holding time is 20min), continuous casting (continuous casting temperature is 1530℃, tundish superheat is 25℃, and casting speed is 1.6m / min) is performed to obtain a continuous casting billet;

[0082] Step S2: After the continuous casting billet is subjected to heating (heating temperature is 1180℃, and holding time is 3h), rolling (two-stage rolling, the rolling temperature of the first stage is 1080℃, the rolling deformation is 45%, the rolling temperature of the second stage is 900℃, the rolling deformation is 40%, and after rolling, water cooling is performed at 4℃ / s to 580℃, and then air cooling is performed to room temperature), an intermediate billet is obtained;

[0083] Step S3: 8 parts of graphene oxide, 12 parts of silicon dioxide are ultrasonically dispersed in 40 parts of deionized water, 60 parts of water-based epoxy resin, 12 parts of curing agent, 0.8 parts of adhesion promoter, 0.2 parts of leveling agent and 0.2 parts of defoaming agent are added and uniformly mixed to obtain a anti-permeation composite coating; the intermediate billet is degreased, the anti-permeation composite coating is coated on the surface of the intermediate billet, and after drying, an anti-permeation composite coating is formed to obtain a high anti-cracking ball flat steel;

[0084] Compared with Example 2, the anti-permeation composite coating is directly coated on the high anti-cracking ball flat steel without carburizing treatment, quenching and tempering treatment, and other steps are the same as those of Example 2.

[0085] Experiment: The high anti-cracking ball flat steels obtained in Examples 1-3 and Comparative Examples 1-3 are taken to prepare samples, and the performance of the samples is detected and the detection results are recorded:

[0086] According to the standard of GB / T 228.1-2021 "Metallic Materials-Tensile Testing-Part 1: Method of Test at Room Temperature", the tensile strength is measured by using an electronic universal testing machine, the tensile speed is 1mm / min; the water contact angle is measured by using a JC2000DM contact angle measuring instrument, the volume of deionized water is 2μL; the corrosion resistance is measured according to GB / T 1771-2007 "Paints and Varnishes-Determination of Resistance to Neutral Salt Spray", the temperature in the salt spray chamber is 35℃, the test solution is 5wt% NaCl solution, and the test time is 720h.

[0087] The test results are as follows:

[0088]

[0089] According to the data in the above table, the following conclusions can be clearly obtained:

[0090] 1、Compared with examples 1-3, the water contact angle and corrosion resistance of the products obtained in Comparative Example 1 and Comparative Example 2 are decreased, which indicates that the modified silica prepared in the application has better hydrophobic property and corrosion resistance than silica; by adding the epoxy group-containing fluorine-containing polyether, fluorine element is introduced, which significantly improves the hydrophobicity and chemical stability of the material, and enhances the corrosion resistance of the coating.

[0091] 2、Compared with examples 1-3, the tensile strength and corrosion resistance of the product obtained in Comparative Example 3 are decreased, which indicates that the present application can improve the microstructure of the material by carburizing, quenching and tempering, thereby improving the tensile strength; at the same time, the surface layer formed by carburizing can block the invasion of corrosive medium, thereby prolonging the service life of the material.

[0092] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the examples should be regarded as exemplary and non-limiting in any respect, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application.

Claims

1. A method of producing a high-ductility, high-chromium, flat-rolled steel, comprising: The method comprises the following steps: ​ Step S1: after raw materials are subjected to converter smelting, LF refining and VD refining, continuous casting is performed to obtain continuous casting billets; Step S2: after the continuous casting billets are heated and rolled, intermediate billets are obtained; the surface of the intermediate billets is degreased, carburizing treatment is performed, and then quenching and tempering treatment are performed to obtain a ball flat steel; Step S3: graphene oxide and modified silicon dioxide are ultrasonically dispersed in deionized water, water-based epoxy resin, curing agent, adhesion promoter, leveling agent and defoaming agent are added and uniformly mixed to obtain an anti-permeation composite coating; the anti-permeation composite coating is coated on the surface of the ball flat steel, and after drying, an anti-permeation composite coating layer is formed to obtain a high-anti-cracking ball flat steel; The raw materials comprise the following elements in percentage by weight: C: 0.08-0.12%, Si: 0.15-0.35%, Mn: 0.5-1.0%, Cr: 0.80-1.0%, Mo: 0.05-0.08%, V: 0.06-0.12%, N: 0.015-0.020%, Nb: 0.04-0.06%, Als: 0.015-0.030%, Ti: 0.01-0.02%, P≤0.02%, S≤0.02%, and the balance is Fe; In the step S2, the rolling is specifically two-stage rolling, the rolling temperature of the first stage is 1050-1100 DEG C, and the rolling deformation is 40-50%; the rolling temperature of the second stage is 850-950 DEG C, and the rolling deformation is 30-50%, and after rolling, water cooling is performed at 2-5 DEG C / s to 550-600 DEG C, and then air cooling is performed to room temperature; The preparation method of the modified silicon dioxide is as follows: Step (1): the silicon dioxide is ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, 3-chloropropyl triethoxysilane is added and uniformly mixed, and the mixture is reacted at 60-70 DEG C for 5-7 h, and then centrifuged, washed and dried to obtain chlorinated silicon dioxide; Step (2): the chlorinated silicon dioxide is ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, branched polyethyleneimine and triethylamine are added and reacted at 30-40 DEG C for 12-24 h, and then filtered, washed and dried to obtain amino-containing silicon dioxide; Step (3): the amino-containing silicon dioxide, anhydrous ethanol and deionized water are uniformly mixed, an epoxy-terminated fluorine-containing polyether is added, and the mixture is reacted for 4-6 h, then dodecenyl succinic anhydride ethanol solution is added to adjust the pH value to 8.4-8.6, and the mixture is reacted at 40-50 DEG C for 5-7 h, and then filtered, washed and dried to obtain the modified silicon dioxide; The preparation steps of the epoxy-terminated fluorine-containing polyether are as follows: under nitrogen protection, hexafluorobisphenol A, trimethylolpropane triglycidyl ether and tetrabutylammonium bromide are uniformly mixed, and the mixture is reacted at 100-110 DEG C for 5-6 h, and then filtered, washed and dried to obtain the epoxy-terminated fluorine-containing polyether.

2. The method of claim 1, wherein the high-ductility flat-rolled steel is produced by the steps of: The process conditions of the continuous casting are as follows: the temperature of the molten steel for continuous casting is 1500-1540 DEG C, the overheat degree of the tundish is 20-30 DEG C, and the casting speed of the casting billet is 1.4-1.8 m / min. ​ 3. The method of claim 1, wherein the high-ductility flat-rolled steel is produced by the steps of: The process conditions of the carburizing treatment in the step S2 are as follows: the mixed gas composed of nitrogen and methanol in a ratio of (1-1.5) m 3 :1L is used as the carburizing agent, the carburizing treatment is carried out in a dripping mode, the holding temperature is 900-950℃, and the holding time is 1-2h. ​ 4. The method of claim 1, wherein the high-ductility flat-rolled steel is produced by the steps of: In the step S2, the process conditions of the tempering are as follows: the tempering temperature is 600-650 DEG C, and the tempering time is 1-2 h. ​ 5. The method of claim 1, wherein the high-ductility flat-rolled steel is produced by the steps of: The anti-permeation composite coating comprises the following components by weight: 50-70 parts of water-based epoxy resin, 5-10 parts of graphene oxide, 10-15 parts of modified silicon dioxide, 30-50 parts of deionized water, 10-15 parts of curing agent, 0.5-1.0 parts of adhesion promoter, 0.1-0.3 parts of leveling agent, and 0.1-0.3 parts of defoaming agent. ​ 6. A high-anti-cracking spherical flat steel prepared by the preparation method according to any one of claims 1-5.

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