Steel for 3C product shell and manufacturing method thereof
A steel composition and manufacturing process for 3C product shells with controlled elements and high-pressure low-temperature annealing optimize microstructure, enhancing magnetic conductivity and durability while maintaining hardness and electroplating quality.
Patent Information
- Application Number
- CN202411223464.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2024-12-10
AI Technical Summary
Existing steel materials for 3C product shells face challenges in balancing magnetic permeability, brittleness, and durability due to factors like alloy additions, microstructure changes, and improper heat treatment, leading to increased hardness and decreased plasticity, which can cause material breakage under stress.
A steel composition with specific elemental limits (C < 0.008%, Si < 0.03%, Mn < 0.3%, Ti = 0.015-0.1%, Al = 0.01-0.08%) and a manufacturing process involving hot rolling, pickling, cold rolling, high-pressure low-temperature annealing, and flattening to optimize microstructure and grain growth, ensuring large grains and uniform hardness.
The solution enhances magnetic conductivity, maintains hardness, improves stamping performance, and ensures a stable electroplating effect, addressing brittleness and durability issues while maintaining performance over time.
Smart Images
Figure HDA0005023736320000011
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of steel materials, and in particular to a steel for a 3C product shell and a manufacturing method thereof. Background Art
[0002] The shell of 3C products has strict requirements on the selection of steel materials, which must ensure the beauty and lightness of the product, as well as sufficient strength and durability. In this field, carbon steel and stainless steel are two commonly used steel materials. Carbon steel has good processing performance and cost-effectiveness. Through the cold rolling process, thin plates with smooth surfaces can be manufactured, which is suitable for 3C product shells with complex shapes and high precision requirements. In addition, through heat treatment and other means, the hardness and strength of carbon steel can be significantly improved to meet the durability requirements of the product.
[0003] Stainless steel has a place in the manufacture of 3C product shells due to its excellent corrosion resistance and easy cleaning. 304 stainless steel is the most common choice, which contains 18% chromium and 8% nickel, which not only gives the material good corrosion resistance, but also enables it to maintain a beautiful appearance after processing. Stainless steel is also relatively strong and hard, which can provide additional protection against wear and impact in daily use.
[0004] When choosing steel, you also need to consider its surface treatment capabilities, such as spraying, electroplating or anodizing, which can not only improve the appearance and texture of the product, but also further enhance the durability and corrosion resistance of the material. Taking all these factors into consideration, the choice of steel will directly affect the performance of the 3C product shell and the end-user experience.
[0005] However, there is a clear requirement for the shell of 3C products, that is, it must be lower than the electromagnetic radiation emitted by the 3C products themselves. However, in the process of increasing the magnetic permeability of current steel, its brittleness may increase due to various factors such as the addition of alloy elements, changes in microstructure, adjustment of grain size, generation of residual stress, occurrence of phase change, influence of cold working and improper heat treatment process.
[0006] These factors may cause a decrease in plasticity and an increase in hardness by affecting the internal structure and stress state of the material, thereby increasing the risk of the material breaking when subjected to impact or stress concentration.
[0007] Therefore, while improving the magnetic conductivity of steel, it is necessary to use sophisticated material design and processing technology control to ensure that the comprehensive performance of the steel meets the application requirements and avoid affecting its performance due to increased brittleness.
[0008] Therefore, a steel for 3C product shell and a manufacturing method thereof are proposed to solve or alleviate the above problems. Summary of the invention
[0009] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a steel for 3C product shell and a manufacturing method thereof.
[0010] In order to achieve the above object, the present invention adopts the following technical solutions:
[0011] A steel for 3C product shells includes the following formula: C < 0.008%, Si < 0.03%, Mn < 0.3%, Ti = 0.015-0.1%, Al = 0.01-0.08%, and the balance is Fe, which may also contain trace amounts of unavoidable impurities.
[0012] Preferably, the formula includes: C<0.006%, Si<0.01%, Mn<0.2%, Ti=0.025-0.08%, Al=0.015-0.06%, and the balance is Fe; it may also contain trace amounts of unavoidable impurities.
[0013] The present invention also provides a method for manufacturing steel for 3C product shells, which is used to produce the above-mentioned steel for 3C product shells, comprising the following steps:
[0014] Prepare ingredients according to the recipe;
[0015] Hot rolling, hot rolling finishing temperature is 800±15℃, hot rolling final rolling coiling temperature is 575±75℃;
[0016] Pickling: pickling the steel after hot rolling with sulfuric acid at a concentration of 10-20%;
[0017] Cold rolling: the pickled steel coil is cold rolled, and the roller roughness during cold rolling is Ra = 0.2-0.6 μm;
[0018] High pressure and low temperature annealing: send the steel into a full hydrogen bell furnace, heat it to 400-450℃ and keep it for 4 hours, then heat it to 575±75℃ after 6 hours, keep it for 10 hours, and then cool it down naturally;
[0019] Post-processing: the cooled steel is flattened to obtain steel for 3C product shells.
[0020] Preferably, in the pickling step, the temperature is controlled at 40±2°C.
[0021] Preferably, the steel material is degreased after pickling.
[0022] The present invention has the following beneficial effects:
[0023] In the present invention, the steel strip achieves significant microstructural optimization through a low-temperature annealing process carried out under a high-pressure environment. Under such high-pressure conditions, the recovery potential energy of the grains of the steel coil increases significantly during the annealing process, thereby enabling the grains to grow at a faster rate to form larger grains. This large-grain structure not only ensures that the magnetic conductivity of the product is significantly improved, but also effectively maintains the hardness of the product surface through low-temperature annealing and subsequent large-scale flattening and stretching treatment, thereby avoiding uneven distribution of hardness.
[0024] In addition, the use of the formula and process described in the present invention to roll the annealed steel strip not only ensures that the product will not have time-limited problems during long-term use, that is, the phenomenon that the performance decreases over time, but also greatly improves the magnetic permeability of the product, making it more efficient and reliable in the field of electromagnetic applications. At the same time, this process also fully considers the hardness, stamping performance, brittleness of the product in the subsequent processing process, and the surface electroplating effect of the final product, ensuring that the steel strip can still maintain excellent comprehensive performance after a series of processing steps to meet the needs of high-end applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0026] Figure 1 This is the metallographic structure diagram of the steel used for the shell of 3C products in the present invention. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.
[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.
[0030] In the description of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the invention is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0031] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.
[0032] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0033] A steel for 3C product shells, comprising the following formula: C < 0.006%, Si < 0.01%, Mn < 0.2%, Ti = 0.025-0.08%, Al = 0.015-0.06%, and the balance is Fe; and it may also contain trace amounts of unavoidable impurities.
[0034] The present invention also provides a method for manufacturing steel for 3C product shells, which is used to produce the above-mentioned steel for 3C product shells, comprising the following steps:
[0035] Prepare ingredients according to the recipe;
[0036] Hot rolling, hot rolling finishing temperature is 800±15℃, hot rolling final rolling coiling temperature is 575±75℃;
[0037] Pickling: pickling the steel after hot rolling with sulfuric acid of 10-20% concentration, and the temperature is controlled at 40±2℃ during the pickling step;
[0038] Cold rolling, degreasing of the steel after pickling, cold rolling of the steel coil after pickling, the roughness of the roll during cold rolling is Ra = 0.2-0.6μm;
[0039] High pressure and low temperature annealing: send the steel into a full hydrogen bell furnace, heat it to 400-450℃ and keep it for 4 hours, then heat it to 575±75℃ after 6 hours, keep it for 10 hours, and then cool it down naturally;
[0040] Post-processing: the cooled steel is flattened to obtain steel for 3C product shells.
[0041] Figure 1 This is the metallographic structure diagram of the steel used for the shell of the 3C product.
[0042] The steel strip with the above formula "C<0.006%, Si<0.01%, Mn<0.2%, Ti=0.025-0.08%, Al=0.015-0.06%, the balance is Fe; it may also contain trace amounts of unavoidable impurities" is annealed at low temperature under high pressure. When the steel coil is annealed under high pressure, the grain recovery potential energy is large, the grains can grow rapidly, the large grains ensure the magnetic conductivity of the product, low temperature annealing and large flat extension ensure the surface hardness of the product, and the steel strip with this formula is rolled and annealed to ensure that the product is free of aging and has high magnetic conductivity, while taking into account the product hardness, stamping performance and surface electroplating effect.
[0043] 1. This is interstitial-free steel. It has no interstitial atoms. The principle is to use Ti element to fix the two major types of interstitial atoms, C and N, so it has no timeliness. This is probably also found in other literature. However, this type is generally used for ultra-low carbon ultra-deep stamping, and the material with no timeliness is relatively rare.
[0044] 2. High magnetic permeability is used for accessories in mobile phones. Some accessories in mobile phones require higher magnetic permeability. There are no interstitial atoms between the grains of this material, the grains are relatively large and relatively uniform, so the magnetic permeability will be better.
[0045] 3. This material is designed based on the special needs of downstream products. By selecting raw material formula and coordinating manufacturing processes, the three parties are combined to achieve the balance of several functions without conflict.
[0046] Among them, the principle of large grain formation is as follows: when low-temperature annealing is performed under high pressure, the stress state inside the material changes, which promotes the recovery and recrystallization of the grains. The high-pressure environment increases the dislocation density inside the grains, and the dislocation movement is more active, which helps the migration of grain boundaries and promotes the growth of grains. The formation of large grains reduces the number of grain boundaries, which are the main source of electron scattering. Reducing grain boundaries can reduce the scattering of electrons in the material, thereby improving the magnetic permeability of the material.
[0047] Among them, the principle of improving magnetic permeability: magnetic permeability refers to the ability of a material to conduct electricity in a magnetic field. Large grains reduce grain boundary scattering and the probability of electron collision in the material, thereby reducing hysteresis loss and improving magnetic permeability. In addition, the fine carbides and oxides formed by Ti and Al elements can act as obstacles to grain growth, further refine the grains, reduce grain boundaries, and further improve magnetic permeability.
[0048] Among them, the principle of no aging: aging is usually related to the instability of the microstructure inside the material, such as the precipitation and phase change of carbides. Since the C content in the steel strip is extremely low, the possibility of carbide precipitation is reduced. At the same time, the addition of Ti and Al can combine with C to form stable carbides, reducing the segregation of carbon at the grain boundary, thereby reducing aging. The high temperature and pressure during the rolling annealing process help eliminate the instability of the microstructure and further ensure that the product is no aging.
[0049] Among them, the principle of hardness and stamping performance guarantee: low temperature annealing helps to maintain the hardness of the material, because the low temperature is not enough to cause significant growth of grains, thereby maintaining the strength of the material. At the same time, large flattening extension improves the microstructure of the material through plastic deformation, improves the plasticity of the material, and thus improves the stamping performance. This balance is crucial for the forming process during the manufacturing process and the performance of the final product.
[0050] Among them, the principle of improving the surface electroplating effect: good surface hardness and flatness help improve the adhesion and uniformity of the electroplating layer. Due to the low content of Si and Mn in the steel strip composition, it helps to reduce the formation of surface oxides, thereby reducing defects in the electroplating process. In addition, plastic deformation during the flattening and stretching process helps to eliminate microscopic defects on the material surface, further improving the electroplating effect.
[0051] Among them, the contribution principle of the composition formula: low C, Si, and Mn content in the steel strip helps to improve the toughness and processing performance of the material. Low C content can reduce the formation of carbides and improve the weldability and toughness of the material. Low Si and Mn content helps to reduce the brittleness of the material. The addition of Ti and Al helps to refine the grains, improve the strength and toughness of the material, and improve the corrosion resistance and oxidation resistance.
[0052] Among them, the principle of the potential impact of trace impurities: Although impurities are generally regarded as unfavorable factors, in some cases they may have a positive impact on the performance of materials through microalloying or other mechanisms. For example, some trace impurities may form complexes with major alloying elements, change the microstructure of the material, and thus improve the performance of the material.
[0053] Among them, the principle of annealing under high pressure: annealing under high pressure can promote plastic deformation inside the material, which is conducive to the uniform growth of grains and the optimization of microstructure. The high pressure environment increases the plasticity of the material, allowing the grains to recrystallize at a lower temperature. This plastic deformation can also reduce the residual stress inside the material, further improving the processing performance and performance of the material.
[0054] Through the above detailed analysis, we can see that the formula and manufacturing method of this steel strip achieves high magnetic permeability, no aging, good hardness, stamping performance and surface electroplating effect by precisely controlling the chemical composition and microstructure of the material, as well as through high pressure and low temperature annealing process, which meets the strict requirements of high-performance electromagnetic equipment and other industrial applications.
[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A steel for 3C product shell, characterized in that: The invention comprises the following formula: C<0.008%, Si<0.03%, Mn<0.3%, Ti=0.015-0.1%, Al=0.01-0.08%, and the balance is Fe, which may also contain trace amounts of inevitable impurities.
2. The steel for 3C product shell according to claim 1, characterized in that: The invention comprises the following formula: C<0.006%, Si<0.01%, Mn<0.2%, Ti=0.025-0.08%, Al=0.015-0.06%, and the balance is Fe; and it may also contain trace amounts of inevitable impurities.
3. A method for manufacturing steel for 3C product shells, used to produce the steel for 3C product shells according to claim 1 or 2, characterized in that: The following steps are included: Prepare ingredients according to the recipe; Hot rolling, hot rolling finishing temperature is 800±15℃, hot rolling final rolling coiling temperature is 575±75℃; Pickling: Use sulfuric acid with a concentration of 10-20% to pickle the steel after hot rolling. Cold rolling: the pickled steel coil is cold rolled, and the roller roughness during cold rolling is Ra = 0.2-0.6 μm; High pressure and low temperature annealing: send the steel into a full hydrogen bell furnace, heat it to 400-450℃ and keep it for 4 hours, then heat it to 575±75℃ after 6 hours, keep it for 10 hours, and then cool it down naturally; Post-processing: the cooled steel is flattened to obtain steel for 3C product shells.
4. The method for manufacturing steel for 3C product shell according to claim 3, characterized in that: In the pickling step, the temperature is controlled at 40±2°C.
5. The method for manufacturing steel for 3C product shell according to claim 3, characterized in that: The steel material after pickling is degreased.