Corrosion-resistant and fracture-resistant steel structural part and machining process thereof

Abstract

The invention discloses a corrosion-resistant and fracture-resistant steel structural part and a machining process thereof, and relates to the technical field of metal materials. The anti-corrosion coating is prepared from the following components: 35-55 parts of epoxy resin, 15-25 parts of organic silicon resin, 4-12 parts of modified mica, 5-15 parts of diglycidyl ether, 3-8 parts of a polyamide resin curing agent, 2-4 parts of a silane coupling agent, 1-3 parts of cellulose acetate butyrate and 0.5-3 parts of dimethyl silicone oil; according to the corrosion-resistant and fracture-resistant steel structural part, through the synergistic effect of steel component design and the anti-corrosion coating, the excellent comprehensive performance is achieved, the anti-corrosion coating forms a compact and high-adhesive-force protection layer on the surface of the steel, and through the double effects of physical barriers and chemical protection, the corrosion resistance and fracture resistance of the steel structural part are improved. And the corrosion resistance and the service life of the steel structural member in a harsh service environment are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, and in particular to a corrosion-resistant and fracture-resistant steel structural part and a processing technology thereof. Background Art

[0002] As one of the most important engineering structural materials, steel has the advantages of high strength, good toughness, and strong weldability. With the development of industrial technology, the performance requirements of steel are constantly increasing, especially in complex service environments with high stress and strong corrosion, which puts higher requirements on the comprehensive performance of steel. Alloying is the core means to improve performance, but the passivation film formed by adding a large amount of Cr and Ni elements (usually Cr ≥ 18%, Ni ≥ 8%) in traditional high-alloy steels (such as austenitic stainless steel) can resist corrosion, but it is accompanied by high costs, increased processing difficulty, and the risk of intergranular corrosion. Although low-alloy steel (total alloy content ≤ 5%) is economical, its corrosion resistance in harsh environments is difficult to meet the needs of long-term service.

[0003] In practical applications, steel structures often face the dual threats of corrosion and fracture. Especially in complex environments such as coastal areas and chemical plants, the erosion of corrosive media such as chloride ions and acid rain can cause pitting corrosion, stress corrosion cracking and other problems in steel, seriously affecting the safety and service life of the structure. These corrosion problems not only cause huge economic losses, but may also cause safety accidents.

[0004] In the existing technology, anti-corrosion measures are concentrated on matrix alloying or surface coating protection. High-alloy steel relies on precious metal stacking (such as 316L stainless steel containing 16% Cr and 10% Ni), which leads to a surge in material costs and is prone to σ phase embrittlement; low-alloy steel is difficult to form a stable passivation film through the action of trace alloying elements (such as Mo and V) alone, and the pitting expansion rate under Cl⁻ erosion is fast. Epoxy resin-based coatings block corrosive media through physical shielding, but their brittle interfaces are prone to cracking and failure under the synergistic effect of stress-corrosion; flaky fillers such as mica are unevenly dispersed due to differences in surface polarity, forming permeation channels that accelerate the infiltration of the medium.

[0005] CN115746656A discloses a water-based inorganic self-curing steel structure anticorrosion coating for steel structure anticorrosion, comprising the following components: zinc powder, water-based epoxy resin, graphene, lithium silicate, modifier, anti-settling agent, film-forming aid, and water. The preparation of the modifier firstly uses glycidol and allyl glycidyl ether as comonomers, synthesizes a skeleton compound with double bond side groups through anionic ring-opening polymerization, and then converts the double bond side groups into sodium sulfonate groups through a "thiol-ene" click reaction between the double bond and the thiol compound to obtain a reaction precursor; then the reaction precursor is made into a copolymer emulsion; and finally the copolymer emulsion is silanized to obtain the product.

[0006] Most of the anti-corrosion coatings in the prior art adopt a single resin system and lack effective shielding components, resulting in insufficient barrier performance of the coating. At the same time, the bonding between the coating and the steel surface mostly relies on physical adsorption, with low interfacial bonding strength, and it is prone to failure due to factors such as temperature changes and mechanical stress during service. In addition, the current research on the surface modification of functional fillers is not deep enough, making it difficult to achieve uniform dispersion and oriented arrangement of the fillers in the coating, which affects the overall protection performance of the coating.

[0007] Therefore, developing a steel structure component with excellent mechanical properties and corrosion resistance is of great significance for ensuring the safety of engineering structures. Under the premise of reasonably controlling costs, this steel structure component should achieve long-term and reliable protection effects through the synergistic effect of optimizing element compatibility and an efficient anti-corrosion coating. Summary of the Invention

[0008] To solve the deficiencies of the prior art, the purpose of the present invention is to provide a corrosion-resistant and fracture-resistant steel structure component and its processing technology. Through the synergistic effect of steel composition design and anti-corrosion coating, the corrosion-resistant and fracture-resistant steel structure component achieves excellent comprehensive performance. The steel has high strength, high toughness, and good welding performance, which can effectively prevent structural fracture; the anti-corrosion coating forms a dense and highly adhesive protective layer on the steel surface, and through the dual effects of physical barrier and chemical protection, significantly improves the corrosion resistance and service life of the steel structure component in harsh service environments.

[0009] To achieve the above purpose, the present invention adopts the following technical solutions: A corrosion-resistant and fracture-resistant steel structure component includes steel and an anti-corrosion coating applied on the surface of the steel. By weight, the anti-corrosion coating is made of the following components: 35 - 55 parts of epoxy resin, 15 - 25 parts of silicone resin, 4 - 12 parts of modified mica, 5 - 15 parts of diglycidyl ether, 3 - 8 parts of polyamide resin curing agent, 2 - 4 parts of silane coupling agent, 1 - 3 parts of cellulose acetate butyrate, and 0.5 - 3 parts of dimethyl silicone oil.

[0010] Preferably, the preparation method of the anti-corrosion coating includes the following steps: After mixing the raw materials except the curing agent evenly, then adding the curing agent and mixing thoroughly to obtain the anti-corrosion coating.

[0011] Preferably, the preparation method of the modified mica includes the following steps: (1) Add mica powder into an ethanol aqueous solution, perform ultrasonic treatment, then add KH570, adjust the pH of the system, heat and stir, and centrifuge, wash, and dry the product to obtain vinyl-modified mica; Silane surface modification: Under acidic conditions, the methoxy group (-OCH 3)(Hydrolysis occurs to generate silanol groups (-Si-OH), which then form Si-O-Si covalent bonds with the Si-OH active sites on the mica surface through a condensation reaction, successfully grafting an organic group containing a C=C double bond onto the mica surface and providing active sites for subsequent mercaptanization reactions.)

[0012] Preferably, in step (1), the particle size of the mica powder is 800 - 1000 mesh.

[0013] Preferably, in step (1), the dosage ratio of the mica powder, the ethanol aqueous solution, and KH570 is 10 g : 100 - 150 mL : 1 - 3 g; the concentration of the ethanol aqueous solution is 92 wt% - 98 wt%.

[0014] Preferably, in step (1), ultrasonic treatment is carried out for 15 - 30 min; the pH of the system is adjusted to 4 - 6 with glacial acetic acid; the heating and stirring conditions are heating and stirring at 60 - 75 °C for 4 - 7 h.

[0015] (2) Disperse the alkenyl-modified mica in THF, carry out ultrasonic treatment, heat up under a nitrogen atmosphere, add AIBN and 4-mercaptobenzaldehyde, stir and react, centrifuge, wash, and dry the product to obtain aldehyde-group-modified mica; Free radical addition: Under nitrogen protection, AIBN thermally decomposes at 60 °C to generate free radicals, which attack the mercapto group to generate sulfur free radicals; the sulfur free radicals undergo anti-Markovnikov addition with the alkenyl double bond to form a carbon free radical intermediate; the carbon free radical undergoes hydrogen transfer with another mercapto group to complete the addition and regenerate the sulfur free radical, realizing a chain reaction. This step successfully introduces aldehyde groups onto the mica surface and provides reaction sites for subsequent reactions.

[0016] Preferably, in step (2), the dosage ratio of the alkenyl-modified mica, THF, AIBN, and 4-mercaptobenzaldehyde is 10 g : 100 - 150 mL : 0.05 - 1 g : 0.8 - 3.2 g.

[0017] Preferably, in step (2), ultrasonic treatment is carried out for 15 - 30 min; heat up to 50 - 65 °C under a nitrogen atmosphere and stir and react for 5 - 8 h.

[0018] (3) Disperse the aldehyde-group-modified mica in an ethanol aqueous solution, carry out ultrasonic treatment, then add triethylamine and 1-(3,4-dihydroxyphenyl)-2-aminoethanol, stir and react, centrifuge, wash, and dry the product to obtain modified mica.

[0019] Schiff base reaction: Triethylamine first activates the aldehyde group to enhance its electrophilicity; the amino group, as a nucleophile, attacks the aldehyde carbon atom, and through an addition-elimination process, a molecule of water is removed to form an imine bond.

[0020] Preferably, in step (3), the dosage ratio of aldehyde group-modified mica, aqueous ethanol solution, triethylamine, and 1-(3,4-dihydroxyphenyl)-2-aminoethanol is 10 g: 100-150 mL: 0.1-0.5 mL: 1-4 g; the concentration of the aqueous ethanol solution is 85 wt% - 95 wt%.

[0021] Preferably, in step (3), ultrasonic treatment is performed for 15-30 min; the stirring reaction conditions are reflux reaction at 60-75 °C for 6-9 h.

[0022] Preferably, the steel is composed of the following elements by weight percentage: C: 0.01% - 0.1%, Cr: 2% - 3.8%, Ni: 3% - 7.2%, Co: 1% - 5.6%, Mo: 0.2% - 5.0%, Mn: 0.1% - 2.0%, Si: 0.2% - 1.0%, N: 0.1% - 0.3%, V: 0.1% - 0.3%, and the balance is iron and inevitable impurities.

[0023] The present invention also claims to protect a processing process of the corrosion-resistant and fracture-resistant steel structure member, including the following steps: preparing a steel raw material according to the element composition, obtaining the steel through smelting, continuous casting, heating, rolling, and heat treatment of the steel raw material, obtaining the steel structure member after welding, and then spraying an anti-corrosion coating onto the sandblasted steel by spraying, spraying two coats, with an interval of 10-30 min between each coat, the thickness of the first coat being 40-60 μm, the thickness of the second coat being 10-30 μm, placing the sprayed member in a room temperature environment for 10-30 min, then putting it into an oven preheated to 150 ± 5 °C for heat preservation for 2-4 h and then taking it out for air cooling to obtain the corrosion-resistant and fracture-resistant steel structure member.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. By reasonably regulating the ratio of alloying elements, the steel structure member of the present invention achieves excellent comprehensive performance: the synergistic effect of Cr, Ni, and Co significantly improves the corrosion resistance and toughness of the steel, the Mo element improves the high-temperature strength and pitting corrosion resistance of the steel, the combined addition of Mn and Si optimizes the deoxidation performance and strength and toughness of the steel, the addition of N and V elements refines the grains and forms a dispersion-distributed carbonitride strengthening phase, effectively improving the strength and toughness of the steel. At the same time, precisely controlling the C content at a low level reduces the tendency to form carbide networks, improving the plasticity, toughness, and welding performance of the steel. In addition, the factory spraying process of two coats and specific curing conditions achieve the best bonding strength between the coating and the substrate.

[0025] 2. The anti-corrosion coating provided by the present invention forms an excellent synergistic protection effect through optimizing the proportioning of each component: the compounding of epoxy resin and silicone resin provides excellent matrix properties and weather resistance, and the flaky structure of the modified mica forms an effective barrier layer in the coating, prolonging the penetration path of the corrosive medium; the diglycidyl ether improves the crosslinking density and adhesion of the coating, and the polyamide resin curing agent ensures the full curing of the coating; the silane coupling agent improves the compatibility of the organic-inorganic phase, and cellulose acetate butyrate adjusts the leveling property and construction performance of the coating. Dimethyl silicone oil, as an antifoaming agent, effectively inhibits the bubble problem during the preparation and construction of the coating, improving the density and smoothness of the coating.

[0026] 3. The modified mica of the present invention achieves multiple synergistic protection effects through three-step surface modification: in the first step, silane modification constructs a stable Si-O-Si covalent bond network on the mica surface, significantly improving the dispersibility and interfacial bonding force of mica in the organic coating matrix; in the second step, the benzene ring structure introduced by free radical addition enhances the shielding effect of the coating and provides a large steric hindrance effect at the same time; in the third step, the imine structure generated by the Schiff base reaction not only improves the film-forming performance of the coating, but more importantly, the introduced ortho-phenol hydroxyl group (catechol structure) can form stable covalent and non-covalent interactions with the steel surface, significantly enhancing the adhesion of the coating to the substrate. In addition, the lamellar structure of the modified mica forms an effective maze effect in the coating, and together with the steric hindrance effect of the surface modification groups, greatly prolongs the diffusion path of the corrosive medium. Through the synergistic effect of physical barrier (lamellar structure) and chemical protection (surface active groups), the mica after multiple modifications realizes the all-round protection of steel. Detailed implementation mode

[0027] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further elaborates on the present invention in conjunction with embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Unless otherwise specified, the chemical reagents and materials in the present invention are all purchased through market channels or synthesized from raw materials purchased through market channels.

[0029] The silicone resin is WT800 pure silicone resin; The epoxy resin is E12; The polyamide resin curing agent is a low molecular weight polyamide resin with an amine value of 200 - 420 mgKOH / g and a molecular weight of 600 - 1000, and is one of products V140, V125 or V115 of Dow Chemical Company.

[0030] A processing technology for corrosion-resistant and fracture-resistant steel structural parts includes the following steps: (1) Add 10 g of mica powder into 100 - 150 mL of an ethanol - aqueous solution with a concentration of 92 wt% - 98 wt%, perform ultrasonic treatment for 15 - 30 min, then add 1 - 3 g of KH570, adjust the pH of the system to 4 - 6 with glacial acetic acid, heat and stir at 60 - 75 °C for 4 - 7 h, centrifuge, wash, and dry the product to obtain vinyl - modified mica; (2) Disperse 10 g of vinyl - modified mica into 100 - 150 mL of THF, perform ultrasonic treatment for 15 - 30 min, heat up to 50 - 65 °C under a nitrogen atmosphere, add 0.05 - 1 g of AIBN and 0.8 - 3.2 g of 4 - mercaptobenzaldehyde, stir and react for 5 - 8 h, centrifuge, wash, and dry the product to obtain aldehyde - modified mica; (3) Disperse 10 g of aldehyde - modified mica into 100 - 150 mL of an ethanol - aqueous solution with a concentration of 85 wt% - 95 wt%, perform ultrasonic treatment for 15 - 30 min, then add 0.1 - 0.5 mL of triethylamine and 1 - 4 g of 1 - (3,4 - dihydroxyphenyl) - 2 - aminoethanol, reflux and react at 60 - 75 °C for 6 - 9 h, centrifuge, wash, and dry the product to obtain modified mica; (4) After uniformly mixing 35 - 55 parts of epoxy resin, 15 - 25 parts of silicone resin, 4 - 12 parts of modified mica, 5 - 15 parts of diglycidyl ether, 2 - 4 parts of silane coupling agent, 1 - 3 parts of cellulose acetate butyrate, and 0.5 - 3 parts of dimethyl silicone oil, then add 3 - 8 parts of polyamide resin curing agent and mix thoroughly to obtain the anti - corrosion coating; (5) Prepare steel raw materials according to the following weight percentage of elements: C: 0.01% - 0.1%, Cr: 2% - 3.8%, Ni: 3% - 7.2%, Co: 1% - 5.6%, Mo: 0.2% - 5.0%, Mn: 0.1% - 2.0%, Si: 0.2% - 1.0%, N: 0.1% - 0.3%, V: 0.1% - 0.3%, with the balance being iron and inevitable impurities; obtain steel through smelting, continuous casting, heating, rolling, and heat treatment, obtain a steel structure part after welding, then spray the anti - corrosion coating onto the sand - blasted steel by spraying, spray two coats, with an interval of 10 - 30 min between each spray, the thickness of the first coat is 40 - 60 μm, the thickness of the second coat is 10 - 30 μm, place the sprayed part in a room - temperature environment for 10 - 30 min, then put it into an oven pre - heated to 150 ± 5 °C, keep it warm for 2 - 4 h, and then take it out and air - cool to obtain the corrosion - resistant and fracture - resistant steel structure part.

[0031] The following is a further description of the present invention through specific examples.

[0032] Example 1 A processing technology for a corrosion - resistant and fracture - resistant steel structure part includes the following steps: (1) Add 10 g of mica powder into 150 mL of 95 wt% ethanol aqueous solution, ultrasonically treat for 20 min, then add 3 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 75 °C for 4 h, centrifuge, wash and dry the product to obtain vinyl-modified mica; (2) Disperse 10 g of vinyl-modified mica into 150 mL of THF, ultrasonically treat for 20 min, heat up to 65 °C under a nitrogen atmosphere, add 1 g of AIBN and 3.2 g of 4-mercaptobenzaldehyde, stir and react for 5 h, centrifuge, wash and dry the product to obtain aldehyde-group modified mica; (3) Disperse 10 g of aldehyde-group modified mica into 150 mL of 90 wt% ethanol aqueous solution, ultrasonically treat for 30 min, then add 0.5 mL of triethylamine and 4 g of 1-(3,4-dihydroxyphenyl)-2-aminoethanol, reflux and react at 75 °C for 6 h, centrifuge, wash and dry the product to obtain modified mica; (4) After uniformly mixing 550 g of epoxy resin, 250 g of silicone resin, 120 g of modified mica, 150 g of diglycidyl ether, 40 g of silane coupling agent KH550, 30 g of cellulose acetate butyrate, and 30 g of dimethyl silicone oil, then add 80 g of polyamide resin curing agent and mix well to obtain the anti-corrosion coating; (5) Prepare steel raw materials according to the following weight percentage of elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and inevitable impurities; obtain steel through smelting, continuous casting, heating, rolling and heat treatment, obtain a steel structure part after welding, then spray the anti-corrosion coating onto the sandblasted steel by spraying, spray two coats, with an interval of 20 min between each coat, the thickness of the first coat is 50 μm, the thickness of the second coat is 20 μm, place the sprayed component in a room temperature environment for 20 min, then put it into an oven preheated to 150 °C, keep it warm for 3 h and then take it out and air-cool to obtain the corrosion-resistant and fracture-resistant steel structure part.

[0033] Example 2 A processing technology for a corrosion-resistant and fracture-resistant steel structure part, comprising the following steps: (1) Add 10 g of mica powder into 150 mL of 95 wt% ethanol aqueous solution, ultrasonically treat for 20 min, then add 2 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 70 °C for 5 h, centrifuge, wash and dry the product to obtain vinyl-modified mica; (2) Disperse 10 g of vinyl-modified mica into 150 mL of THF, ultrasonically treat for 20 min, heat to 60 °C under a nitrogen atmosphere, add 0.8 g of AIBN and 2.4 g of 4-mercaptobenzaldehyde, stir and react for 6 h, centrifuge, wash, and dry the product to obtain aldehyde-group-modified mica; (3) Disperse 10 g of aldehyde-group-modified mica into 150 mL of 90 wt% ethanol aqueous solution, ultrasonically treat for 30 min, then add 0.5 mL of triethylamine and 4 g of 1-(3,4-dihydroxyphenyl)-2-aminoethanol, reflux and react at 75 °C for 6 h, centrifuge, wash, and dry the product to obtain modified mica; (4) After uniformly mixing 500 g of epoxy resin, 200 g of silicone resin, 100 g of modified mica, 120 g of diglycidyl ether, 30 g of silane coupling agent KH550, 20 g of cellulose acetate butyrate, and 20 g of dimethyl silicone oil, then add 60 g of polyamide resin curing agent and mix thoroughly to obtain the anti-corrosion coating; (5) Prepare steel raw materials according to the following weight percentage elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and unavoidable impurities; obtain steel through smelting, continuous casting, heating, rolling, and heat treatment, obtain a steel structure part after welding, then spray the anti-corrosion coating onto the sandblasted steel by spraying method, spray two coats, with an interval of 20 min between each coat, the thickness of the first coat is 50 μm, the thickness of the second coat is 20 μm, place the sprayed component in a room-temperature environment for 20 min, then put it into an oven preheated to 150 °C, keep it warm for 3 h, and then take it out and air-cool to obtain the corrosion-resistant and fracture-resistant steel structure part.

[0034] Example 3 A processing technology for a corrosion-resistant and fracture-resistant steel structure part, comprising the following steps: (1) Add 10 g of mica powder into 150 mL of 95 wt% ethanol aqueous solution, ultrasonically treat for 20 min, then add 2 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 65 °C for 6 h, centrifuge, wash, and dry the product to obtain vinyl-modified mica; (2) Disperse 10 g of vinyl-modified mica into 150 mL of THF, ultrasonically treat for 20 min, heat to 55 °C under a nitrogen atmosphere, add 0.3 g of AIBN and 1.6 g of 4-mercaptobenzaldehyde, stir and react for 7 h, centrifuge, wash, and dry the product to obtain aldehyde-group-modified mica; (3) Disperse 10 g of aldehyde group - modified mica into 150 mL of 90 wt% ethanol - aqueous solution, ultrasonically treat for 30 min, then add 0.2 mL of triethylamine and 2 g of 1-(3,4 - dihydroxyphenyl)-2 - aminoethanol, reflux and react at 65 °C for 8 h, centrifuge, wash, and dry the product to obtain modified mica; (4) After uniformly mixing 400 g of epoxy resin, 200 g of silicone resin, 60 g of modified mica, 80 g of diglycidyl ether, 30 g of silane coupling agent KH550, 20 g of cellulose acetate butyrate, and 10 g of dimethyl silicone oil, then add 40 g of polyamide resin curing agent and mix well to obtain the anti - corrosion coating; (5) Prepare steel raw materials according to the following weight percentage of elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and unavoidable impurities; obtain steel through smelting, continuous casting, heating, rolling, and heat treatment, obtain a steel structure part after welding, then spray the anti - corrosion coating onto the sand - blasted steel by spraying, spray two coats, with an interval of 20 min between each coat, the thickness of the first coat is 50 μm, the thickness of the second coat is 20 μm, place the sprayed component in a room - temperature environment for 20 min, then put it into an oven pre - heated to 150 °C, keep it warm for 3 h, and then take it out and air - cool to obtain the corrosion - resistant and fracture - resistant steel structure part.

[0035] Example 4 A processing technology for a corrosion - resistant and fracture - resistant steel structure part, comprising the following steps: (1) Add 10 g of mica powder into 150 mL of 95 wt% ethanol - aqueous solution, ultrasonically treat for 20 min, then add 1 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 60 °C for 7 h, centrifuge, wash, and dry the product to obtain vinyl - modified mica; (2) Disperse 10 g of vinyl - modified mica into 150 mL of THF, ultrasonically treat for 20 min, heat up to 50 °C under a nitrogen atmosphere, add 0.05 g of AIBN and 0.8 g of 4 - mercaptobenzaldehyde, stir and react for 8 h, centrifuge, wash, and dry the product to obtain aldehyde - modified mica; (3) Disperse 10 g of aldehyde - modified mica into 150 mL of 90 wt% ethanol - aqueous solution, ultrasonically treat for 30 min, then add 0.1 mL of triethylamine and 1 g of 1-(3,4 - dihydroxyphenyl)-2 - aminoethanol, reflux and react at 60 °C for 9 h, centrifuge, wash, and dry the product to obtain modified mica; (4) After uniformly mixing 350 g of epoxy resin, 150 g of silicone resin, 40 g of modified mica, 50 g of diglycidyl ether, 20 g of silane coupling agent KH550, 10 g of cellulose acetate butyrate, and 5 g of dimethyl silicone oil, 30 g of polyamide resin curing agent is added and mixed thoroughly to obtain the anti-corrosion coating; (5) Prepare steel raw materials according to the following weight percentage of elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and inevitable impurities; the steel is obtained through smelting, continuous casting, heating, rolling, and heat treatment, and the steel structure part is obtained after welding. Then, the anti-corrosion coating is sprayed onto the sandblasted steel by spraying method, spraying two coats, with an interval of 20 min between each coat. The thickness of the first coat is 50 μm, and the thickness of the second coat is 20 μm. After the sprayed component is placed at room temperature for 20 min, it is put into an oven preheated to 150 °C, kept warm for 3 h, and then taken out and air-cooled to obtain the corrosion-resistant and fracture-resistant steel structure part.

[0036] Comparative Example 1 A processing technology for a corrosion-resistant and fracture-resistant steel structure part includes the following steps: (1) Add 10 g of mica powder to 150 mL of 95 wt% ethanol aqueous solution, ultrasonically treat for 20 min, then add 3 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 75 °C for 4 h, centrifuge, wash, and dry the product to obtain vinyl-modified mica; (2) Disperse 10 g of vinyl-modified mica in 150 mL of THF, ultrasonically treat for 20 min, raise the temperature to 65 °C under a nitrogen atmosphere, add 1 g of AIBN and 3.2 g of 4-mercaptobenzaldehyde, stir and react for 5 h, centrifuge, wash, and dry the product to obtain aldehyde-modified mica; (3) After uniformly mixing 550 g of epoxy resin, 250 g of silicone resin, 120 g of aldehyde-modified mica, 150 g of diglycidyl ether, 40 g of silane coupling agent KH550, 30 g of cellulose acetate butyrate, and 30 g of dimethyl silicone oil, 80 g of polyamide resin curing agent is added and mixed thoroughly to obtain the anti-corrosion coating; (4)Prepare steel raw materials with the following weight percentages of elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and inevitable impurities; obtain steel through smelting, continuous casting, heating, rolling, and heat treatment, obtain a steel structure part after welding, then spray the anti-corrosion coating onto the sandblasted steel by spraying, spray two coats, with an interval of 20 min between each coat, the thickness of the first coat is 50 μm, the thickness of the second coat is 20 μm, place the sprayed part in a room-temperature environment for 20 min, then put it into an oven preheated to 150 °C, keep it warm for 3 h, take it out and air-cool it to obtain the corrosion-resistant and fracture-resistant steel structure part.

[0037] Comparative Example 2 A processing technology for a corrosion-resistant and fracture-resistant steel structure part, comprising the following steps: (1) Add 10 g of mica powder to 150 mL of 95 wt% ethanol aqueous solution, ultrasonically treat for 20 min, then add 3 g of KH570, adjust the pH of the system to 5 with glacial acetic acid, heat and stir at 75 °C for 4 h, centrifuge, wash, and dry the product to obtain vinyl-modified mica; (2) After uniformly mixing 550 g of epoxy resin, 250 g of silicone resin, 120 g of vinyl-modified mica, 150 g of diglycidyl ether, 40 g of silane coupling agent KH550, 30 g of cellulose acetate butyrate, and 30 g of dimethyl silicone oil, then add 80 g of polyamide resin curing agent, and mix well to obtain the anti-corrosion coating; (3) Prepare steel raw materials with the following weight percentages of elements: C: 0.05%, Cr: 2.9%, Ni: 5.1%, Co: 3.3%, Mo: 2.6%, Mn: 1.5%, Si: 0.6%, N: 0.2%, V: 0.2%, and the balance is iron and inevitable impurities; obtain steel through smelting, continuous casting, heating, rolling, and heat treatment, obtain a steel structure part after welding, then spray the anti-corrosion coating onto the sandblasted steel by spraying, spray two coats, with an interval of 20 min between each coat, the thickness of the first coat is 50 μm, the thickness of the second coat is 20 μm, place the sprayed part in a room-temperature environment for 20 min, then put it into an oven preheated to 150 °C, keep it warm for 3 h, take it out and air-cool it to obtain the corrosion-resistant and fracture-resistant steel structure part.

[0038] The performance of the anti-corrosion coatings prepared in Examples 1-4 and Comparative Examples 1-2 was tested. Referring to GB / T 1728-2020 "Determination of drying time of paint film and putty film", the surface drying time was measured; referring to GB / T 5210-2006 "Pull-off adhesion test for paints and varnishes", the breaking strength of the coating was measured, and the substrate for testing was steel; referring to GB / T 1732-2020 "Determination of impact resistance of paint films", the impact resistance of the coating was measured; referring to GB 9274-1988 "Determination of resistance of paints and varnishes to liquid media", the acid and alkali resistance of the coating was measured; referring to GB / T 1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes", the salt spray resistance of the coating was measured; the specific data are shown in Table 1.

[0039] Table 1 Performance test results of anti-corrosion coatings

[0040] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A corrosion-resistant and fracture-resistant steel structural part, comprising a steel material and an anti-corrosion coating applied on the surface of the steel material, characterized in that: The anti-corrosion coating is made of the following components in parts by weight: 35-55 parts of epoxy resin, 15-25 parts of silicone resin, 4-12 parts of modified mica, 5-15 parts of bisglycidyl ether, 3-8 parts of polyamide resin curing agent, 2-4 parts of silane coupling agent, 1-3 parts of cellulose acetate butyrate, and 0.5-3 parts of dimethyl silicone oil.

2. The corrosion-resistant and fracture-resistant steel structural member according to claim 1, characterized in that: The preparation method of the modified mica comprises the following steps: (1) adding mica powder to an ethanol aqueous solution, ultrasonically treating it, then adding KH570, adjusting the pH of the system, heating and stirring, centrifuging, washing, and drying the product to obtain olefin-modified mica; (2) dispersing the olefin-modified mica in THF, ultrasonically treating it, heating it under a nitrogen atmosphere, adding AIBN and 4-mercaptobenzaldehyde, stirring to react, centrifuging, washing, and drying the product to obtain aldehyde-modified mica; (3) Dispersing the aldehyde-modified mica in an ethanol aqueous solution, ultrasonically treating it, then adding triethylamine and 1-(3,4-dihydroxyphenyl)-2-aminoethanol, stirring to react, centrifuging, washing, and drying the product to obtain modified mica.

3. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (1), the dosage ratio of mica powder, ethanol aqueous solution and KH570 is 10 g: 100-150 mL: 1-3 g; and the concentration of ethanol aqueous solution is 92 wt%-98 wt%.

4. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (1), ultrasonic treatment is performed for 15 to 30 minutes; the pH value of the system is adjusted to 4 to 6 with glacial acetic acid; and heating and stirring conditions are heating and stirring at 60 to 75° C. for 4 to 7 hours.

5. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (2), the usage ratio of olefin-modified mica, THF, AIBN and 4-mercaptobenzaldehyde is 10 g: 100-150 mL: 0.05-1 g: 0.8-3.2 g.

6. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (2), ultrasonic treatment is performed for 15 to 30 minutes; the temperature is raised to 50 to 65° C. under a nitrogen atmosphere, and the reaction is stirred for 5 to 8 hours.

7. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (3), the dosage ratio of aldehyde-modified mica, ethanol aqueous solution, triethylamine, and 1-(3,4-dihydroxyphenyl)-2-aminoethanol is 10 g: 100-150 mL: 0.1-0.5 mL: 1-4 g; and the concentration of the ethanol aqueous solution is 85 wt%-95 wt%.

8. The corrosion-resistant and fracture-resistant steel structural member according to claim 2, characterized in that: In step (3), the ultrasonic treatment is performed for 15 to 30 minutes; and the stirring reaction conditions are reflux reaction at 60 to 75° C. for 6 to 9 hours.

9. The corrosion-resistant and fracture-resistant steel structural member according to claim 1, characterized in that: The steel material is composed of the following elements in percentage by weight: C: 0.01%~0.1%, Cr: 2%~3.8%, Ni: 3%~7.2%, Co: 1%~5.6%, Mo: 0.2%~5.0%, Mn: 0.1%~2.0%, Si: 0.2%~1.0%, N: 0.1%~0.3%, V: 0.1%~0.3%, and the remainder is iron and inevitable impurities.

10. A processing technology for a corrosion-resistant and fracture-resistant steel structural member according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: preparing steel raw materials according to elemental composition, subjecting the steel raw materials to smelting, continuous casting, heating, rolling and heat treatment to obtain steel, welding to obtain steel structural parts, and then spraying anti-corrosion coating onto the sandblasted steel by spraying, spraying two layers, each layer having an interval of 10 to 30 minutes, the first layer having a coating thickness of 40 to 60 μm, and the second layer having a coating thickness of 10 to 30 μm, placing the sprayed components in a room temperature environment for 10 to 30 minutes, placing them in an oven preheated to 150±5°C for insulation for 2 to 4 hours, and then taking them out for air cooling to obtain the corrosion-resistant and fracture-resistant steel structural parts.

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