A method of producing steel

Abstract

The application discloses a steel production method, and forms a microstructure on the surface of a sample; a relationship function of a friction coefficient changing with roughness is obtained according to the friction coefficient values and the roughness values of multiple samples; a first threshold interval of the friction coefficient is determined, and a second threshold interval of the roughness is obtained through the relationship function of the friction coefficient changing with the roughness, wherein, in the second threshold interval, the friction coefficient value and the roughness value are inversely proportional; and the microstructure is formed on the surface of a steel plate, so that the roughness of the surface of the steel plate is within the second threshold interval. The steel production method realizes accurate control of the surface performance of the steel, guarantees the formability of the steel processed into parts, and avoids problems such as poor appearance and surface quality of the parts.

Description

Technical Field

[0001] This invention relates to Steel stamping The field of technology relates, in particular, to a method for producing steel. Background Technology

[0002] After being coated, steel plates have advantages such as resistance to high-temperature oxidation and corrosion, and can be used to process various parts.

[0003] The surface of the steel sheet coating needs to be processed to a certain shape to control the surface properties of the material. If the performance of the coating is not well controlled, cracking and wrinkling are likely to occur when the steel sheet is processed into parts, resulting in a low stamping forming rate. Different parts require different stamping parameters and have different requirements for the surface properties of the steel sheet. If the surface properties of the steel cannot be accurately controlled according to the requirements, problems such as poor appearance and surface quality of the parts can easily occur. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a method for producing steel that overcomes or at least partially solves the above problems.

[0005] A method for producing steel is provided, comprising:

[0006] Create a sample and form a microstructure on the sample surface;

[0007] Based on the friction coefficient and roughness values ​​of multiple samples, the relationship function between friction coefficient and roughness was obtained.

[0008] A first threshold range for the friction coefficient is determined, and a second threshold range for the roughness is obtained through the relationship function between the friction coefficient and the roughness. Within the second threshold range, the friction coefficient value and the roughness value are inversely proportional.

[0009] Microstructures are formed on the surface of the steel plate, so that the surface roughness of the steel plate is within the second threshold range.

[0010] Optional, create sample images, including:

[0011] Multiple steel sheets are produced according to the standard process for the steel to be produced, and a coating is processed on the surface of the steel sheets to obtain sample sheets.

[0012] Optionally, microstructures are formed on the sample surface, including:

[0013] A smoothing roller with a set surface morphology is used to roll and form microstructures on the coating surface of the sample, so that the coating surface of the sample has a set roughness.

[0014] Optionally, based on the friction coefficient and roughness values ​​of multiple samples, a function relating the friction coefficient to roughness can be obtained, including:

[0015] Using the roughness value of the same sample as the independent variable and the friction coefficient value as the dependent variable, a variable point coordinate is formed;

[0016] By fitting the coordinates of variable points on multiple samples, the relationship function between the friction coefficient and roughness is obtained.

[0017] Optionally, a first threshold range for the coefficient of friction is determined, including:

[0018] Based on the required range of surface friction coefficients for the steel to be produced, a first threshold range is formed.

[0019] Optionally, the second threshold range of roughness can be obtained through the relationship function between the friction coefficient and roughness, including:

[0020] Substitute the first maximum value within the first threshold interval into the relational function to obtain the first minimum value within the second threshold interval;

[0021] Substituting the second minimum value within the first threshold interval into the relational function yields the second maximum value within the second threshold interval.

[0022] Optionally, the first threshold interval is (0, 0.15).

[0023] Optionally, an aluminum-silicon coating is provided on the surface of the steel plate, and a microstructure is formed on the aluminum-silicon coating, such that the first threshold interval is [0.1158, 0.1272], and the friction coefficient of the aluminum-silicon coating is a real number within the first threshold interval; the second threshold interval is [1.159, 1.489], and the roughness of the aluminum-silicon coating is a real number within the second threshold interval; in the first threshold interval, the relationship function between the friction coefficient of the aluminum-silicon coating and the roughness is: μ=-0.0345Ra+0.1672, where μ is the friction coefficient and Ra is the roughness.

[0024] Optionally, after ensuring that the surface roughness of the steel plate is within the second threshold range, the method further includes: applying lubricating oil to the surface of the steel plate, transferring the steel plate onto a stamping die, and stamping to obtain a part.

[0025] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0026] The steel production method provided in this invention obtains the relationship function between the surface roughness of the coating and the coefficient of friction using a sample of the steel to be produced, determines the correspondence between roughness and coefficient of friction, obtains the applicable roughness range based on the required coefficient of friction range, and performs microstructure processing on the surface of the steel coating according to the roughness range, thereby achieving precise control of the surface properties of the steel, ensuring the formability of the steel processed into parts, and avoiding problems such as poor appearance and surface quality of parts.

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0029] Figure 1 This is a flowchart of the steel production process according to an embodiment of the present invention. Detailed Implementation

[0030] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0031] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0032] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0033] This invention provides a method for producing steel; please refer to [the relevant documentation]. Figure 1 , Figure 1 This is a flowchart of steel production according to an embodiment of the present invention. The method includes:

[0034] S1, Prepare a sample and form a microstructure on the surface of the sample;

[0035] S2, based on the friction coefficient and roughness values ​​of multiple samples, obtain the relationship function between the friction coefficient and roughness.

[0036] S3, determine the first threshold range of the friction coefficient, and obtain the second threshold range of the roughness through the relationship function of the friction coefficient with the roughness. In the second threshold range, the friction coefficient value and the roughness value are inversely proportional.

[0037] S4 forms a microstructure on the surface of the steel plate, so that the surface roughness of the steel plate is within the second threshold range.

[0038] The implementation process steps of this embodiment are described in detail below with examples:

[0039] We provide steel for processing, with an aluminum-silicon coating on its surface. This coating offers advantages such as resistance to high-temperature oxidation and corrosion, making it suitable for manufacturing parts like exhaust pipes. However, this material also has certain drawbacks. For instance, the lubrication characteristics of the aluminum-silicon coating need to be evaluated and controlled during stamping. Poor surface performance control can affect stamping formability and cause powdering. Inadequate surface stamping performance can lead to cracking and wrinkling. Excessive friction during stamping can cause forming difficulties and powdering. Excessive friction damages the coating during forming, resulting in powdering and cracking. Once powdering occurs, the coating surface turns black because the detached coating mixes with lubricating oil, turning black during friction. Powdering also affects the appearance of parts and the surface quality of the mold.

[0040] The specific operation of producing steel with an aluminum-silicon coating (hereinafter referred to as the steel to be produced) using the above-mentioned solution provided in the embodiments of the present invention is as follows:

[0041] Step S1 involves creating sample sheets. Multiple steel sheets are produced according to the standard process for the steel to be produced. A coating is then applied to the surface of the steel sheets to obtain the sample sheets. The material and process parameters of the sample sheets are exactly the same as those of the steel to be produced. Microstructures are formed on the surface of the sample sheets using a smoothing roller with a set surface morphology. This roller is used to roll and form the microstructures on the coated surface of the sample sheets, giving the coated surface of the sample sheets a set roughness.

[0042] When steel is stamped into parts in a mold, it needs to be coated with lubricating oil. Material surface properties mainly refer to the microstructure of the surface morphology, which directly determines the roughness of the steel coating surface. When the roughness value of the steel surface coating is too small, the oil retention is poor; when the surface roughness is too large, it is also not conducive to stamping. Therefore, to ensure surface condition and lubrication characteristics, the roughness is usually set within a certain range. Therefore, the roughness Ra value is used as a surface characteristic index. Steel is processed and manufactured in the form of strip steel during production, hence hereinafter referred to as strip steel. The surface roughness of the strip steel is controlled by the finishing rolls during the strip steel production process. The finishing rolls have uneven surfaces of different depths. When the finishing rolls roll the strip steel, they transfer the morphology of the finishing roll surface onto the strip steel surface, resulting in strip steel surfaces with different uneven surfaces, i.e., different roughnesses. Therefore, for coated strip steel, after the strip steel is produced, the surface morphology of the strip steel is controlled by the finishing rolls. Strip steel describes a processing state of steel, which can be understood here as having the same meaning as steel.

[0043] The above steps involve using smoothing rollers of different shapes and specifications to process different microstructures on the sample surface, thereby producing experimental samples with various surface roughnesses.

[0044] When steel plates are processed into parts, they need to be coated with lubricating oil for die stamping. Samples are used to test the properties of the lubricating oil and select the optimal one. By preparing test samples of steel plates and strips, applying a quantitative amount of oil, and conducting friction tests, the coefficient of friction for different types of lubricating oil is determined, and the lubrication effect of different oils is determined based on the coefficient of friction. Generally, lubricating oils with good lubrication performance have a low coefficient of friction. This process is used to test the characteristics of different lubricating oils, allowing for selection based on their specific properties in production. Because different materials have different adaptability to lubricating oils, to improve the scientific rigor, lubricating oil compatibility tests can be conducted for different types of steel.

[0045] Taking DC54D+AS aluminum-silicon coated cold-stamping steel sheet as an example, steel sheets of the same specification are used to produce strip samples with the same stretching speed, clamping pressure, and number of stretching cycles. The sample size is 0.5*45*(400-500). A strip friction testing machine is used to test the characteristics of the lubricating oil, with an oil content of 800mg / m³. 2 The measurement results are shown in Table 1 below:

[0046]

[0047]

[0048] Table 1

[0049] As shown in Table 1, sample 1, without lubricant, has a friction coefficient of 0.124. Sample 2, using PAC 550 lubricant, has a friction coefficient of 0.123, not significantly different from the result without lubricant, indicating that this lubricant is the least effective for cold-stamping steel sheets with DC54D+AS aluminum-silicon coating. Sample 5, using Fuchs 3802 lubricant, has the lowest friction coefficient of 0.098, demonstrating the best lubrication effect. However, a lower friction coefficient is not always better during steel sheet stamping. The friction coefficient of the steel sheet should be controlled within a suitable range based on the characteristics of the product being processed.

[0050] In an optional implementation, operation S2 is performed to obtain the relationship function between the friction coefficient and roughness based on the friction coefficient and roughness values ​​of multiple samples. Specifically, the roughness value of the same sample is used as the independent variable, and the friction coefficient value as the dependent variable, forming a variable point coordinate system. The variable point coordinates of multiple samples are fitted to obtain the relationship function between the friction coefficient and roughness. After manufacturing experimental samples with different surface roughnesses, the friction coefficient of the sample is checked. The friction coefficient can be tested using a strip tensile friction testing machine or a reciprocating friction testing machine. This step involves testing the friction coefficient corresponding to different surface roughnesses. For example, multiple strip steel samples with different surface roughnesses are prepared for the aluminum-silicon coated steel to be produced, and then friction coefficient tests are performed for different surface roughnesses. Through these friction coefficient tests, the correspondence between different surface roughnesses and the friction coefficient of the steel can be obtained.

[0051] Friction tests were conducted on samples with surfaces of different roughness to detect the coefficients of friction for these samples. Operation S3 was then performed to determine a first threshold range for the coefficient of friction. Specifically, this range was determined based on the required range of surface friction coefficients for the steel to be produced. A second threshold range for roughness was then obtained using a function relating the coefficient of friction to surface roughness. This was achieved by substituting the first maximum value within the first threshold range into the function to obtain the first minimum value of the second threshold range, and then substituting the second minimum value into the function to obtain the second maximum value of the second threshold range.

[0052] Generally, to ensure material formability, the coefficient of friction is required to be less than or equal to 0.15, meaning the first threshold range is (0, 0.15). Different parts have different characteristics, therefore the required critical coefficient of friction for the steel also differs. The first maximum and second minimum values ​​within the first threshold range for steel vary depending on the part being processed. Generally, a lower coefficient of friction is better. For different parts, the critical coefficient of friction for the steel can be determined through simulation. By establishing a simulation model, setting simulation conditions based on actual working conditions, and then conducting simulations with different coefficients of friction, the critical coefficient of friction for the part can be determined.

[0053] For example, if a steel plate has an aluminum-silicon coating on its surface, and microstructures are formed on this coating, the optimal friction coefficient range for this steel when used to process exhaust pipes is 0.1158–0.1272. The relationship between friction coefficient and roughness established in operation S3 is: μ = -0.0345Ra + 0.1672, where μ is the friction coefficient and Ra is the roughness. Substituting the minimum required friction coefficient of 0.1272 into this formula yields a roughness value of 1.489. Substituting the maximum required friction coefficient of 0.1158 into the formula yields a roughness value of 1.159. The resulting roughness range is 1.159–1.489 μm. This roughness range ensures a friction coefficient below 0.15, guaranteeing the surface friction characteristics and formability of the material.

[0054] Operation S4 is performed to form a microstructure on the steel plate surface, ensuring that the surface roughness falls within the second threshold range. For steel plates with an aluminum-silicon coating, the required range for the surface friction coefficient is determined to be 0.1158–0.1272, resulting in a roughness range of 1.159–1.489 μm. Based on this roughness requirement, a corresponding finishing roll is selected for actual steel plate production. After determining the optimal roughness value, the morphology of the finishing roll is chosen for production practice based on this roughness. Therefore, the produced strip steel surface possesses this roughness value, ensuring that the friction coefficient meets the requirements during production.

[0055] Finally, after the S4 operation is completed, apply lubricating oil to the surface of the steel plate, transfer the steel plate to the stamping die, set the stamping parameters, and stamp the required parts.

[0056] The solution of this invention is not limited to steel plates with aluminum-silicon coatings; the method is also applicable to cold-stamped steel plates with pure zinc coatings and zinc-aluminum-magnesium coatings.

[0057] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0058] The steel production method provided in this invention obtains the relationship function between the surface roughness of the coating and the coefficient of friction using a sample of the steel to be produced, determines the correspondence between roughness and coefficient of friction, obtains the applicable roughness range based on the required coefficient of friction range, and performs microstructure processing on the surface of the steel coating according to the roughness range, thereby achieving precise control of the surface properties of the steel, ensuring the formability of the steel processed into parts, and avoiding problems such as poor appearance and surface quality of parts.

[0059] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0060] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the foregoing description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the disclosed aspects consist of fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this disclosure.

[0061] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in a claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A method for producing steel, characterized in that, include: The process of making a sample sheet and forming a microstructure on the surface of the sample sheet includes: producing multiple steel sheets according to the standard process of the steel to be produced, processing a coating on the surface of the steel sheets to obtain the sample sheet, and forming a microstructure on the surface of the sample sheet by using a smoothing roller with a set surface morphology to roll and form the microstructure on the coating surface of the sample sheet, so that the coating surface of the sample sheet has a set roughness. Based on the friction coefficient and roughness values ​​of multiple samples, a relationship function between the friction coefficient and the roughness is obtained. Determine a first threshold range for the coefficient of friction; wherein, determining the first threshold range for the coefficient of friction includes: forming the first threshold range based on the required range of the surface friction coefficient of the steel to be produced, wherein the first threshold range is (0, 0.15]. The second threshold range of the roughness is obtained by using the relationship function between the friction coefficient and the roughness, wherein the friction coefficient value and the roughness value are inversely proportional within the second threshold range; The microstructure is formed on the surface of the steel plate, so that the surface roughness of the steel plate is within the second threshold range.

2. The steel production method as described in claim 1, characterized in that, The step of obtaining the relationship function between the friction coefficient and the roughness based on the friction coefficient values ​​and roughness values ​​of multiple samples includes: Using the roughness value of the same sample as the independent variable and the friction coefficient value as the dependent variable, a variable point coordinate is formed; By fitting the coordinates of variable points on multiple samples, a function relating the friction coefficient to the roughness is obtained.

3. The steel production method as described in claim 1, characterized in that, The step of obtaining the second threshold range of roughness through the relationship function between the friction coefficient and the roughness includes: Substitute the first maximum value within the first threshold interval into the relational function to obtain the first minimum value of the second threshold interval; Substituting the second minimum value within the first threshold interval into the relational function yields the second maximum value within the second threshold interval.

4. The steel production method as described in claim 1, characterized in that, The steel plate surface is provided with an aluminum-silicon coating, and the microstructure is formed on the aluminum-silicon coating; the first threshold interval is [0.1158, 0.1272], and the friction coefficient of the aluminum-silicon coating is a real number within the first threshold interval; the second threshold interval is [1.159, 1.489], and the roughness of the aluminum-silicon coating is a real number within the second threshold interval; in the first threshold interval, the relationship function between the friction coefficient of the aluminum-silicon coating and the roughness is: μ = -0.0345Ra + 0.1672, where μ is the friction coefficient and Ra is the roughness.

5. The steel production method as described in claim 1, characterized in that, After ensuring that the surface roughness of the steel plate is within the second threshold range, the process further includes: applying lubricating oil to the surface of the steel plate, transferring the steel plate onto a stamping die, and stamping to obtain a part.

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