Cold-drawn section steel with self-repairing function and preparation method thereof

Abstract

The invention relates to the technical field of profile steel preparation, in particular to cold-drawn profile steel with a self-repairing function and a preparation method thereof.The cold-drawn profile steel with the self-repairing function comprises a steel base body, the steel base body has the preset section shape and size, and the surface of the steel base body is subjected to nanocrystallization treatment to form nanoscale roughness so that the binding force between the steel base body and a self-repairing layer can be enhanced; the self-repairing layer is coated on at least one part of the surface of the steel substrate; the cold-drawn section steel with the self-repairing function has the beneficial effects that the cold-drawn section steel with the self-repairing function is successfully developed by introducing innovative technical characteristics such as nanocrystallization treatment, a microencapsulation self-repairing technology and an intelligent response catalyst and optimizing components of the self-repairing layer, the mechanical property of the cold-drawn section steel is remarkably improved, and the service life of the cold-drawn section steel is remarkably prolonged; and the possibility is provided for the application in wider fields.

Description

Technical Field

[0001] The present invention relates to the field of section steel preparation, and particularly to a cold-drawn section steel with self-healing function and its preparation method. Background Technique

[0002] In the modern industrial field, cold-drawn section steel, as an important structural material, is widely used in many fields such as machinery manufacturing, construction, automobile manufacturing, bridge construction, and aerospace due to its high strength, good dimensional accuracy, and surface finish. However, during the use of cold-drawn section steel, it will inevitably be subjected to various external forces, such as alternating loads, impact loads, etc. These external forces may cause cracks or damages on the surface or inside of the steel, thereby affecting its mechanical properties and service life.

[0003] Once traditional cold-drawn section steel generates cracks or damages, it often needs to be repaired by means such as welding, riveting, or replacing new parts. These repair methods not only have high costs, but may also cause secondary damage to the steel during the repair process, reducing its overall performance. Therefore, it is particularly important to develop a cold-drawn section steel with self-healing function.

[0004] As a new type of intelligent material, self-healing materials can automatically or under external stimuli repair cracks or damages when the materials are damaged and restore their original properties. Currently, the research on self-healing materials mainly focuses on polymer-based composites, ceramic-based composites, and metal-based composites, etc. Among them, the microencapsulation self-healing technology has attracted much attention due to its high repair efficiency, simple operation, etc. This technology microencapsulates the repair agent and embeds it into the matrix material. When the material is damaged, the microcapsules rupture to release the repair agent, and the repair agent cures under the action of a catalyst, thereby repairing cracks or damages.

[0005] However, applying self-healing technology to cold-drawn section steel still faces many challenges. On the one hand, the surface of cold-drawn section steel is smooth, and the bonding force with the self-healing layer is weak, which easily leads to the shedding of the self-healing layer; on the other hand, the performance of the self-healing layer needs to meet the requirements of cold-drawn section steel in terms of high strength, corrosion resistance, wear resistance, etc., and also needs to have an intelligent repair function, that is, it can accurately repair according to the degree and location of cracks or damages. Summary of the Invention

[0006] The purpose of the present invention is to provide a cold-drawn section steel with self-healing function and its preparation method to solve the problems raised in the above background technique.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A cold-drawn section steel with self-healing function, the cold-drawn section steel includes:

[0008] A steel substrate, which has a predetermined cross-sectional shape and size, and its surface is subjected to nanometer treatment to form a nanoscale roughness, so as to enhance the bonding force with the self-repairing layer;

[0009] A self-repairing layer, which is coated on at least a part of the surface of the steel substrate and is composed of the following components in parts by weight: 30-45 parts of self-repairing material, 8-12 parts of binder, 2-4 parts of intelligent response catalyst, and 1-3 parts of reinforcing filler; the self-repairing material contains a microencapsulated epoxy resin-based repair agent, and the microcapsule wall material is a polymer with shape memory function, which changes its shape and ruptures under the stimulation of cracks or damages to release the repair agent, realizing the self-repairing function.

[0010] Preferably, in the microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to the microcapsule wall material is 9:1 to 11:1, and the microcapsule also contains a small amount of nanoparticles, and the nanoparticles are selected from one or more of silica, titanium dioxide or carbon nanotubes, so as to improve the mechanical properties and durability of the repair agent.

[0011] Preferably, the binder is a modified epoxy resin, in which the weight ratio of epoxy resin to the modifier is 4:1 to 6:1, and the binder also contains 1-2 parts of anti-corrosion additive to improve the corrosion resistance of the self-repairing layer; the modifier is selected from one or more of polyetheramine, polythiol or fatty amine.

[0012] Preferably, the intelligent response catalyst is a temperature-sensitive or pH-sensitive catalyst, which is activated or deactivated according to the change of environmental temperature or the microenvironment at the crack, so as to control the release and curing speed of the repair agent.

[0013] Preferably, the reinforcing filler is a fibrous reinforcing material, which is selected from one or more of glass fiber, carbon fiber or aramid fiber, with a length of 10-50 microns and a diameter of 1-5 microns, so as to improve the strength and toughness of the self-repairing layer.

[0014] A method for preparing a cold-drawn steel with self-repairing function, comprising the following steps:

[0015] Provide a steel billet with a predetermined cross-sectional shape and size;

[0016] Perform cold drawing on the steel billet to obtain a cold-drawn steel;

[0017] Perform nanometer treatment on the surface of the cold-drawn steel to form a nanoscale roughness;

[0018] Prepare a coating containing self-repairing material, binder, intelligent response catalyst and reinforcing filler;

[0019] The coating is evenly applied to at least a part of the surface of the cold-drawn steel by ultrasonic spraying to form a self-healing layer, and the coating thickness is 30-60 microns;

[0020] The cold-drawn steel coated with the self-healing layer is subjected to stepwise temperature-rising curing treatment at a temperature of 90-110 °C. First, it is preheated at 60 °C for 0.5 hours, then the temperature is raised to 90-110 °C for curing treatment for 3-5 hours, and finally it is naturally cooled to room temperature.

[0021] Preferably, before formulating the coating, it also includes the step of surface pretreatment of the steel billet. The surface pretreatment includes degreasing, pickling, alkali washing, rinsing with clean water, and passivation treatment in sequence, thoroughly removing the oil stains and scale impurities on the surface of the steel billet, and forming a protective film to improve the adhesion of the coating.

[0022] Preferably, during the ultrasonic spraying process, the ultrasonic frequency is 20-40 kHz, the spraying pressure is 0.5-0.7 MPa, and the spraying distance is 200-300 mm, ensuring that the coating is evenly applied to the surface of the cold-drawn steel and forming a dense self-healing layer.

[0023] Preferably, during the stepwise temperature-rising curing treatment, a vacuum-assisted curing technology is adopted, that is, a vacuum degree of -0.05 MPa to -0.1 MPa is applied during the curing process to remove the bubbles and volatile components in the self-healing layer and improve the density and performance of the self-healing layer.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The cold-drawn steel with self-healing function and its preparation method proposed by the present invention form a nano-scale roughness by nano-treating the surface of the cold-drawn steel, significantly enhancing the bonding force between the steel matrix and the self-healing layer and effectively preventing the shedding of the self-healing layer.

[0026] The self-healing layer contains microencapsulated epoxy resin-based repair agent. The microcapsule wall material has shape memory function and can change its shape and rupture to release the repair agent under the stimulation of cracks or damages. At the same time, the intelligent response catalyst can be activated or deactivated according to the change of the environmental temperature or the microenvironment at the crack, thereby controlling the release and curing speed of the repair agent and realizing the intelligent repair function.

[0027] The self-healing layer is composed of self-healing material, binder, intelligent response catalyst and reinforcing filler. By optimizing the ratio and selection of each component, the self-healing layer has excellent corrosion resistance, high strength, good wear resistance and good fatigue resistance, meeting the use requirements of cold-drawn steel under high strength and harsh environmental conditions.

[0028] The cold-drawn steel with self-healing function can automatically or under external stimulation repair cracks or damages when damaged, restore its original performance, thus extending its service life and reducing maintenance costs.

[0029] The cold-drawn steel with self-healing function proposed by the present invention is applicable to multiple fields such as mechanical manufacturing, construction, automobile manufacturing, bridge construction, aerospace, etc. Especially in applications that need to withstand alternating loads, harsh environmental conditions, and high temperature and high pressure for a long time, it has significant advantages. Brief Description of the Drawings

[0030] Figure 1 It is a flow chart of the method of the present invention. Detailed Embodiments

[0031] In order to clearly and completely describe the objectives, technical solutions of the present invention, and make the advantages more clearly understood, the following further details the embodiments of the present invention with reference to the drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, not to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0032] Embodiment 1, the invention provides a technical solution: a cold-drawn steel with self-healing function and its preparation method.

[0033] Preparation of the steel matrix: Provide steel billets with a predetermined cross-sectional shape (such as circular, square, etc.) and size. Perform cold drawing on the steel billets to obtain cold-drawn steel that meets the requirements.

[0034] Surface nanocrystallization treatment of the steel matrix: Use nanocrystallization treatment technology (such as physical or chemical methods) to treat the surface of the cold-drawn steel to form a nanoscale roughness to enhance the bonding force with the self-healing layer.

[0035] Preparation of the self-healing layer coating: Self-healing material: 40 parts (including microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to microcapsule wall material is 10:1, and a small amount of silica nanoparticles are included in the microcapsules). Binder: 10 parts (modified epoxy resin, the weight ratio of epoxy resin to polyetheramine modifier is 5:1, including 1.5 parts of anti-corrosion additive). Intelligent response catalyst: 3 parts (temperature-sensitive catalyst). Reinforcing filler: 2 parts (glass fiber, with a length of 30 microns and a diameter of 3 microns).

[0036] Coating application: Uniformly apply the prepared coating on the surface of the cold-drawn steel by ultrasonic spraying. The ultrasonic frequency is 30 kHz, the spraying pressure is 0.6 MPa, and the spraying distance is 250 mm. The coating thickness is 45 microns.

[0037] Curing treatment: Stepwise temperature rise curing treatment is carried out at a temperature of 90 - 110°C: First, preheat at 60°C for 0.5 hours, then raise the temperature to 100°C for curing treatment for 4 hours, and finally cool naturally to room temperature.

[0038] Product performance: The prepared cold-drawn steel has excellent corrosion resistance, high strength, good self-healing performance, excellent wear resistance, and good fatigue resistance.

[0039] Example 2, the invention provides a technical solution: A cold-drawn steel with self-healing function and its preparation method.

[0040] Steel matrix preparation: Provide a steel billet with a predetermined cross-sectional shape (such as rectangular) and size. Carry out cold drawing on the steel billet to obtain a cold-drawn steel that meets the requirements.

[0041] Steel matrix surface pretreatment and nanometer treatment: Perform degreasing, pickling, alkali washing, rinsing with clear water, and passivation treatment in sequence to thoroughly remove impurities such as oil stains and scale on the surface of the steel billet and form a protective film. Perform nanometer treatment on the surface of the treated cold-drawn steel to form a nanoscale roughness.

[0042] Self-healing layer coating formulation: Self-healing material: 35 parts (including microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to microcapsule wall material (with shape memory function) is 9:1, and a small amount of titanium dioxide nanoparticles are included in the microcapsule). Binder: 12 parts (modified epoxy resin, the weight ratio of epoxy resin to polythiol modifier is 4:1, including 1 part of anti-corrosion additive). Intelligent response catalyst: 4 parts (pH-sensitive catalyst). Reinforcing filler: 1 part (carbon fiber, with a length of 10 microns and a diameter of 1 micron).

[0043] Coating application: The prepared coating is evenly applied to the surface of the cold-drawn steel by ultrasonic spraying. The ultrasonic frequency is 20 kHz, the spraying pressure is 0.5 MPa, and the spraying distance is 200 mm. The coating thickness is 30 microns.

[0044] Curing treatment: Stepwise temperature rise curing treatment is carried out at a temperature of 90 - 110°C: First, preheat at 60°C for 0.5 hours, then raise the temperature to 90°C for curing treatment for 5 hours, and finally cool naturally to room temperature. Adopt vacuum-assisted curing technology and apply a vacuum degree of -0.05 MPa.

[0045] Product performance: The prepared cold-drawn steel has excellent corrosion resistance, high strength, intelligent self-healing performance, excellent wear resistance, and good fatigue resistance.

[0046] Embodiment 3: The invention provides a technical solution: a cold-drawn steel section with self-repairing function and a preparation method thereof.

[0047] Steel matrix preparation: Provide a steel billet with a predetermined cross-sectional shape (such as hexagonal) and size. Cold-draw the steel billet to obtain a cold-drawn steel section that meets the requirements.

[0048] Nano-treatment of steel substrate surface: Use nano-treatment technology to treat the surface of cold-drawn steel to form nano-scale roughness.

[0049] Self-healing coating formulation: Self-healing material: 45 parts (including microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to microcapsule wall material is 11:1, and the microcapsules contain a small amount of carbon nanotubes). Binder: 8 parts (modified epoxy resin, in which the weight ratio of epoxy resin to fatty amine modifier is 6:1, including 2 parts of anti-corrosion additives). Smart response catalyst: 2 parts (temperature-sensitive catalyst). Reinforcement filler: 3 parts (aramid fiber, length 50 microns, diameter 5 microns).

[0050] Paint coating: The prepared paint is evenly coated on the surface of the cold-drawn steel by ultrasonic spraying, with an ultrasonic frequency of 40kHz, a spraying pressure of 0.7MPa, and a spraying distance of 300mm. The coating thickness is 60 microns.

[0051] Curing treatment: Step-by-step curing treatment at 90-110°C: preheat at 60°C for 0.5 hours, then heat to 110°C for curing for 3 hours, and finally cool naturally to room temperature. Vacuum-assisted curing technology is used, and a vacuum degree of -0.1MPa is applied.

[0052] Product performance: The prepared cold-drawn steel has excellent corrosion resistance, high strength, efficient self-repairing performance, excellent wear resistance and good fatigue resistance.

[0053] Embodiment 4, the invention provides a technical solution: a cold-drawn steel section with self-repairing function and a preparation method thereof.

[0054] Steel matrix preparation: Provide a steel billet with a predetermined cross-sectional shape (such as an ellipse) and size. Cold-draw the steel billet to obtain a cold-drawn steel section that meets the requirements.

[0055] Steel substrate surface pretreatment and nano-treatment: degreasing, pickling, alkali washing, water washing and passivation treatment are carried out in sequence to completely remove oil stains, scale and other impurities on the surface of the steel billet and form a protective film. The surface of the cold-drawn steel is nano-treated to form nano-level roughness.

[0056] Self-healing layer coating formulation: Self-healing material: 30 parts (including microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to microcapsule wall material is 10:1, and a small amount of silicon dioxide and titanium dioxide nanoparticles are contained in the microcapsules). Binder: 11 parts (modified epoxy resin, where the weight ratio of epoxy resin to polyetheramine and polythiol composite modifier is 5:1, including 1 part of anti-corrosion additive). Intelligent response catalyst: 3 parts (temperature-sensitive and pH-sensitive composite catalyst). Reinforcing filler: 2.5 parts (a mixture of glass fiber and carbon fiber, with lengths of 20 microns and 30 microns respectively, and diameters of 2 microns and 3 microns respectively).

[0057] Coating application: The prepared coating is evenly applied to the surface of cold-drawn steel by ultrasonic spraying. The ultrasonic frequency is 35 kHz, the spraying pressure is 0.65 MPa, and the spraying distance is 275 mm. The coating thickness is 50 microns.

[0058] Curing treatment: Stepwise heating curing treatment is carried out at a temperature of 90 - 110 °C: First, preheat at 60 °C for 0.5 hours, then raise the temperature to 105 °C for curing treatment for 4 hours, and finally cool naturally to room temperature. Vacuum-assisted curing technology is adopted, and a vacuum degree of -0.075 MPa is applied.

[0059] Product performance: The prepared cold-drawn steel has excellent corrosion resistance, high strength, intelligent self-healing performance, excellent wear resistance, and good fatigue resistance, and is particularly suitable for occasions that need to withstand alternating loads and harsh environmental conditions for a long time.

[0060] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cold-drawn steel with self-repairing function, characterized in that: The cold drawn steel comprises: A steel substrate having a predetermined cross-sectional shape and size, and a surface that has been nano-processed to form a nano-scale roughness to enhance the bonding force with the self-repairing layer; A self-repairing layer is coated on at least a portion of the surface of a steel substrate and is composed of the following components in parts by weight: 30-45 parts of a self-repairing material, 8-12 parts of a binder, 2-4 parts of an intelligent response catalyst, and 1-3 parts of a reinforcing filler; the self-repairing material comprises a microencapsulated epoxy resin-based repairing agent, the wall material of the microcapsule is a polymer with shape memory function, which changes shape and ruptures to release the repairing agent under the stimulation of cracks or damage, thereby realizing a self-repairing function.

2. The cold-drawn steel with self-repairing function according to claim 1, characterized in that: In the microencapsulated epoxy resin-based repair agent, the weight ratio of epoxy resin to microcapsule wall material is 9:1 to 11:1, and the microcapsules also contain trace amounts of nanoparticles, which are selected from one or more of silicon dioxide, titanium dioxide or carbon nanotubes, to improve the mechanical properties and durability of the repair agent.

3. The cold-drawn steel with self-repairing function according to claim 1, characterized in that: The binder is a modified epoxy resin, wherein the weight ratio of the epoxy resin to the modifier is 4:1 to 6:1, and the binder also contains 1-2 parts of an anti-corrosion additive to improve the corrosion resistance of the self-repairing layer; the modifier is selected from one or more of polyetheramine, polythiol or fatty amine.

4. The cold-drawn steel with self-repairing function according to claim 1, characterized in that: The intelligent response catalyst is a temperature-sensitive or pH-sensitive catalyst, which is activated or deactivated according to changes in ambient temperature or microenvironment at the crack, thereby controlling the release and curing speed of the repair agent.

5. The cold-drawn steel with self-repairing function according to claim 1, characterized in that: The reinforcing filler is a fibrous reinforcing material selected from one or more of glass fiber, carbon fiber or aramid fiber, with a length of 10-50 microns and a diameter of 1-5 microns, which improves the strength and toughness of the self-repairing layer.

6. A method for preparing a cold-drawn steel section with self-repairing function as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Providing steel billets of predetermined cross-sectional shape and size; The steel billet is cold drawn to obtain a cold drawn steel section; The surface of cold-drawn steel is nano-processed to form nano-scale roughness; formulating coatings containing self-healing materials, binders, smart responsive catalysts, and reinforcing fillers; The coating is evenly applied on at least a portion of the surface of the cold-drawn steel by ultrasonic spraying to form a self-repairing layer with a coating thickness of 30-60 microns; The cold-drawn steel coated with the self-repairing layer is subjected to a step-by-step temperature curing treatment at a temperature of 90-110°C, first preheated at 60°C for 0.5 hour, then heated to 90-110°C for curing for 3-5 hours, and finally naturally cooled to room temperature.

7. A preparation method according to claim 6, characterized in that: Before preparing the coating, the step of surface pretreatment of the steel billet is also included. The surface pretreatment includes degreasing, pickling, alkali washing, water rinsing and passivation treatment in sequence to completely remove oil stains, oxide scale impurities on the surface of the steel billet and form a protective film to improve the adhesion of the coating.

8. A preparation method according to claim 6, characterized in that: During the ultrasonic spraying process, the ultrasonic frequency is 20-40kHz, the spraying pressure is 0.5-0.7MPa, and the spraying distance is 200-300mm, ensuring that the coating is evenly coated on the surface of the cold-drawn steel and forms a dense self-repairing layer.

9. A preparation method according to claim 6, characterized in that: During the step-temperature curing process, vacuum-assisted curing technology is used, that is, a vacuum degree of -0.05MPa to -0.1MPa is applied during the curing process to remove bubbles and volatiles in the self-repairing layer and improve the density and performance of the self-repairing layer.

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