Preparation method of stainless steel special-shaped wire for automobile windscreen wiper

Abstract

The invention discloses a preparation method of a stainless steel special-shaped wire for an automobile windscreen wiper, and relates to the technical field of stainless steel, and the preparation method specifically comprises the following steps: sequentially carrying out rough drawing treatment and primary online bright annealing treatment on a hot-rolled wire rod to obtain the stainless steel special-shaped wire; and the stainless steel special-shaped wire is subjected to fine drawing treatment and secondary online bright annealing treatment in sequence, and the stainless steel special-shaped wire for the automobile windscreen wiper is obtained. Compared with the prior art, the method has the advantages that by optimizing the hot working and surface treatment processes in stages, the problems of non-uniform internal structure and surface defects of the material caused by unstable heat treatment and concentrated drawing stress in the traditional preparation process are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of stainless steel technology, and more specifically, to a method for preparing stainless steel profiled wires for automotive windshield wipers. Background Technology

[0002] As a critical safety component ensuring clear driving visibility, the performance of the core material of automotive windshield wipers—stainless steel shaped wire—directly affects the reliability and lifespan of the wiper system. In recent years, with the automotive industry's increasing demands for lightweight, weather-resistant, and aesthetically pleasing components, stainless steel shaped wire, due to its high strength and corrosion resistance, has gradually become the mainstream material in windshield wiper manufacturing. However, current technologies still face multiple technical bottlenecks in the preparation of shaped wire.

[0003] In traditional manufacturing processes, stainless steel shaped wires often suffer from uneven internal structure due to unstable heat treatment, easily leading to surface defects such as black and yellow lines, scratches, and cracks. This not only affects the product's appearance quality but also reduces the material's fatigue resistance, accelerating wiper failure under long-term high-frequency vibration conditions. Furthermore, some processes employ rough drawing forming, frequently resulting in folding and peeling due to stress concentration, leading to decreased yield and increased production costs. Simultaneously, existing production technologies have limitations in controlling the material's mechanical properties; some products struggle to balance strength and elongation, making wipers prone to plastic deformation or fracture under extreme temperatures or complex operating conditions, thus hindering the overall vehicle safety performance.

[0004] Although the industry has attempted to improve material quality through methods such as optimizing mold design, adjusting lubricant formulations, or introducing surface passivation treatments, the aforementioned defects remain difficult to eradicate due to insufficient process synergy. For example, while a single surface treatment technology can mask some appearance defects, it cannot eliminate internal stress concentration problems; and simply improving drawing parameters may sacrifice production efficiency or increase energy consumption. The limitations of existing technologies not only lead to insufficient product market competitiveness but also pose serious challenges to the durability and user experience of automotive wiper systems. Against this backdrop, there is an urgent need to develop an innovative solution for systematically optimizing the preparation process of stainless steel shaped wires to achieve a synergistic improvement in material surface quality, internal microstructure uniformity, and comprehensive mechanical properties. Summary of the Invention

[0005] This invention systematically eliminates surface defects and improves internal structure uniformity by synergistically optimizing staged hot working and multi-stage online bright annealing processes. This achieves a synergistic improvement in the high strength, toughness, corrosion resistance, and surface smoothness of wiper stainless steel wire, while significantly increasing production efficiency and product yield.

[0006] This invention provides a method for preparing stainless steel shaped wires for automotive windshield wipers, the method specifically including the following steps: S1. Hot-rolled wire rod is subjected to rough drawing and one online bright annealing process to obtain stainless steel shaped wire. S2. The stainless steel shaped wire obtained in step S1 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for automotive windshield wipers.

[0007] Compared with existing technologies, this invention effectively solves the problems of uneven internal structure and surface defects caused by unstable heat treatment and concentrated drawing stress in traditional manufacturing processes by optimizing the hot working and surface treatment processes in stages. It employs a multi-pass hot rolling and online bright annealing synergistic process to refine the grain structure and eliminate residual processing stress, reducing appearance defects such as black and yellow lines, cracks, and folds from the source. The staged drawing combined with two bright annealing treatments gradually adjusts the material's deformation energy storage and internal stress distribution, avoiding surface damage such as peeling and scratches, while achieving synergistic optimization of material strength and elongation. This significantly improves the corrosion resistance, fatigue resistance, and dimensional stability of the wiper stainless steel wire. Simultaneously, continuous process design improves production efficiency and product yield, meeting the core requirements of automotive wiper systems for high reliability and long service life.

[0008] In one possible implementation, in step S1, the raw material for the stainless steel shaped wire is composed of the following components by mass percentage: C: ≤0.030%, 0.30%≤Si≤0.60%, 0.30%≤Mn≤0.60%, P: ≤0.030%, S: ≤0.020%, 0.20%≤Ni≤0.60%, 0.20%≤Cu≤0.60%, N: ≤0.40%, 18.00%≤Cr≤19.50%, 0.30%≤Nb≤0.70%.

[0009] Compared with existing technologies, this invention significantly improves the purity and corrosion resistance of raw materials by strictly controlling impurity content and optimizing alloy composition ratio. High chromium content enhances the material's oxidation resistance, while the synergistic effect of titanium and nickel effectively inhibits the tendency of high-temperature intergranular corrosion. Low sulfur and phosphorus content reduces the risk of cracking during hot working, improving the uniformity of the material's internal structure from the source, thereby reducing the probability of surface defects during subsequent forming. At the same time, it enhances the material's comprehensive mechanical properties and high-temperature service stability, meeting the core requirements of windshield wipers for high weather resistance, long service life, and appearance quality.

[0010] In one possible implementation, in step S1, the diameter of the hot-rolled wire rod is 5.5 mm.

[0011] In one possible implementation, in step S1, the surface area reduction rate of the roughing process is 80-90%.

[0012] Compared with existing technologies, the synergistic optimization of roughing with high surface area reduction and subsequent online bright annealing effectively promotes a reasonable distribution of dislocation density and refines the grain structure within the material, reducing defects such as surface folds and cracks caused by excessive deformation. Precise control of metal flow and work hardening not only enhances the material's strength reserves but also eliminates residual stress through online annealing, suppressing surface damage such as black and yellow lines and scratches from the processing level. This ensures that the stainless steel shaped wire possesses high strength and toughness, surface smoothness, and dimensional stability, meeting the stringent requirements of windshield wipers for fatigue resistance and appearance quality.

[0013] In one possible implementation, the parameters for a single online bright annealing process in step S1 are as follows: temperature 700-900℃, annealing speed 3-9m / min.

[0014] Compared with existing technologies, the synergistic process of precise temperature control and dynamic adjustment of annealing speed effectively optimizes the material recrystallization process, reduces surface black lines and decarburization defects caused by high-temperature oxidation, refines grains and homogenizes internal structure, and eliminates the risk of cracks and folds caused by processing stress concentration. The gradient energy release mechanism further balances the material strength and ductility, ensuring that the stainless steel shaped wire has both high surface finish, low defect density and excellent strength and toughness matching, significantly improving the fatigue resistance and appearance consistency of wiper components.

[0015] In one possible implementation, in step S2, the surface reduction rate of the fine-drawing process is 70-85%.

[0016] Compared with existing technologies, the synergistic process of fine drawing with high surface area reduction and secondary online bright annealing gradually optimizes the deformation energy storage and internal stress distribution of the material, effectively eliminating residual stress accumulated in the early processing and reducing surface defects such as peeling and folding. The precise cold working deformation combined with dynamic annealing energy control not only improves the grain refinement and dislocation uniformity of the material and enhances fatigue resistance, but also maintains surface smoothness and dimensional accuracy. Ultimately, it achieves a synergistic balance between high strength, high ductility and corrosion resistance of stainless steel profiled wire, meeting the core requirements of long-term reliability of wiper components under complex working conditions.

[0017] In one possible implementation, the parameters for the secondary online bright annealing process in step S2 are as follows: temperature is 700-900℃, and annealing speed is 5-12m / min.

[0018] Compared with existing technologies, the precise control process of dynamically matching annealing temperature and speed effectively balances the recrystallization and grain growth rate of the material, reduces surface black lines and decarburization defects caused by high-temperature oxidation, refines the grains and homogenizes the internal stress distribution, and eliminates residual strain and crack tendency accumulated by fine drawing. The gradient energy input mechanism further optimizes the material strength and toughness matching, improves surface smoothness and dimensional stability, and ensures that the stainless steel shaped wire has high fatigue resistance, corrosion resistance and forming accuracy, meeting the long service life and high reliability requirements of wiper components under complex working conditions.

[0019] In one possible implementation, both the primary online bright annealing and the secondary online bright annealing are performed in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0020] Compared with existing technologies, the synergistic regulation of a nitrogen-hydrogen mixed protective atmosphere effectively isolates the high-temperature oxidation environment, inhibits surface decarburization and oxide scale formation, and fundamentally eliminates defects such as black and yellow lines and oxide spots. The specific gas ratio optimizes the thermodynamic conditions, promotes uniform recrystallization of the material and refines the grain structure, reducing the risk of cracks and folds caused by residual stress concentration. The dynamically stable protective atmosphere system further ensures the uniformity of the annealing process, improves the material's corrosion resistance, surface smoothness and grain boundary bonding strength, and enables the stainless steel shaped wire to have high ductility, fatigue resistance and long service life, meeting the high reliability requirements of wiper components under complex working conditions. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0022] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0024] Example 1 This embodiment provides a stainless steel shaped wire for automotive windshield wipers, which is prepared by the following method: S1. The stainless steel profiled wire for automotive windshield wipers is composed of the following components by mass percentage: C: 0.02%, Si: 0.45%, Mn: 0.45%, P: 0.01%, S: 0.01%, Ni: 0.40%, Cu: 0.4%, N: 0.20%, Cr: 18.0%, Nb: 0.30%, with the balance being Fe and unavoidable impurities. The diameter of the resulting hot-rolled wire rod is 5.50 mm. S2. The hot-rolled wire rod is subjected to rough drawing and one online bright annealing treatment to obtain stainless steel shaped wire. The surface reduction rate of the rough drawing treatment is 80%. The parameters of the one online bright annealing treatment are as follows: temperature is 700℃, annealing speed is 3m / min. S3. The stainless steel shaped wire obtained in step S2 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for automobile windshield wipers. The surface reduction rate of the fine drawing is 70%. The parameters of the secondary online bright annealing are as follows: temperature is 700℃ and annealing speed is 5m / min. Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0025] Example 2 This embodiment provides a stainless steel shaped wire for automotive windshield wipers, which is prepared by the following method: S1. The stainless steel profiled wire for automotive windshield wipers is composed of the following components by mass percentage: C: 0.01%, Si: 0.30%, Mn: 0.30%, P: 0.02%, S: 0.01%, Ni: 0.30%, Cu: 0.45%, N: 0.10%, Cr: 18.0%, Nb: 0.30%, with the balance being Fe and unavoidable impurities. The diameter of the resulting hot-rolled wire rod is 5.50 mm. S2. The hot-rolled wire rod is subjected to rough drawing and one online bright annealing treatment to obtain stainless steel shaped wire. The surface reduction rate of the rough drawing treatment is 82%. The parameters of the one online bright annealing treatment are as follows: temperature is 750℃, annealing speed is 4m / min. S3. The stainless steel shaped wire obtained in step S2 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for car windshield wipers. The surface reduction rate of the fine drawing is 75%. The parameters of the secondary online bright annealing are as follows: temperature is 750℃ and annealing speed is 7m / min. Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0026] Example 3 This embodiment provides a stainless steel shaped wire for automotive windshield wipers, which is prepared by the following method: S1. The stainless steel profiled wire for automotive windshield wipers is composed of the following components by mass percentage: C: 0.02%, Si: 0.45%, Mn: 0.5%, P: 0.01%, S: 0.01%, Ni: 0.60%, Cu: 0.50%, N: 0.20%, Cr: 19.0%, Nb: 0.45%, with the balance being Fe and unavoidable impurities. The diameter of the resulting hot-rolled wire rod is 5.50 mm. S2. The hot-rolled wire rod is subjected to rough drawing and one online bright annealing treatment to obtain stainless steel shaped wire. The surface reduction rate of the rough drawing treatment is 85%. The parameters of the one online bright annealing treatment are as follows: temperature is 800℃, annealing speed is 6m / min. S3. The stainless steel shaped wire obtained in step S2 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for car windshield wipers. The area reduction rate of fine drawing is 78%. The parameters of secondary online bright annealing are as follows: temperature is 800℃ and annealing speed is 8m / min. Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0027] Example 4 This embodiment provides a stainless steel shaped wire for automotive windshield wipers, which is prepared by the following method: S1. The raw material of stainless steel profiled wire for automotive wipers is melted, hot-rolled, and used as the base material with a diameter of 5.50 mm. The raw material of stainless steel profiled wire for automotive wipers is composed of the following components by mass percentage: C: 0.01%, Si: 0.30%, Mn: 0.45%, P: 0.02%, S: 0.01%, Ni: 0.20%, Cu: 0.45%, N: 0.30%, Cr: 19.0%, Nb: 0.60%, with the balance being Fe and unavoidable impurities. The diameter of the obtained hot-rolled wire rod is 5.50 mm. S2. The hot-rolled wire rod is subjected to rough drawing and one online bright annealing treatment to obtain stainless steel shaped wire. The surface reduction rate of the rough drawing treatment is 88%. The parameters of the one online bright annealing treatment are as follows: temperature is 850℃, annealing speed is 8m / min. S3. The stainless steel shaped wire obtained in step S2 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for car windshield wipers. The area reduction rate of the fine drawing is 84%. The parameters of the secondary online bright annealing are as follows: temperature is 850℃ and annealing speed is 11m / min. Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0028] Example 5 This embodiment provides a stainless steel shaped wire for automotive windshield wipers, which is prepared by the following method: S1. The raw material of stainless steel profiled wire for automotive wipers is melted, hot-rolled, and used as the base material with a diameter of 5.50 mm. The raw material of stainless steel profiled wire for automotive wipers is composed of the following components by mass percentage: C: 0.030%, Si: 0.46%, Mn: 0.60%, P: 0.01%, S: 0.01%, Ni: 0.60%, Cu: 0.60%, N: 0.40%, Cr: 19.50%, Nb: 0.70%, with the balance being Fe and unavoidable impurities. The diameter of the obtained hot-rolled wire rod is 5.50 mm. S2. The hot-rolled wire rod is subjected to rough drawing and one online bright annealing treatment to obtain stainless steel shaped wire. The surface reduction rate of the rough drawing treatment is 90%. The parameters of the one online bright annealing treatment are as follows: temperature is 900℃, annealing speed is 9m / min. S3. The stainless steel shaped wire obtained in step S2 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for automobile windshield wipers. The surface reduction rate of the fine drawing is 85%. The parameters of the secondary online bright annealing are as follows: temperature is 900℃ and annealing speed is 12m / min. Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.

[0029] The inventors conducted performance tests on the stainless steel shaped wires for automotive windshield wipers prepared in Examples 1-5, and the test results are as follows: The tensile strength of the stainless steel profiled wire used in the automotive windshield wiper of Example 1 is 457 N / mm². 2 It has an elongation of 29% and a glossy surface, free from defects such as black or yellow lines, scratches, cracks, folds, and peeling.

[0030] The tensile strength of the stainless steel profiled wire used in the automotive windshield wiper in Example 2 is 485 N / mm². 2 It has an elongation of 28% and a glossy surface, free from defects such as black or yellow lines, scratches, cracks, folds, and peeling.

[0031] The tensile strength of the stainless steel profiled wire used in the automotive windshield wiper in Example 3 is 507 N / mm². 2 It has an elongation of 30% and a glossy surface, free from defects such as black or yellow lines, scratches, cracks, folds, and peeling.

[0032] The tensile strength of the stainless steel profiled wire for automotive windshield wipers in Example 4 is 522 N / mm². 2 It has an elongation of 26% and a glossy surface, free from defects such as black or yellow lines, scratches, cracks, folds, and peeling.

[0033] The tensile strength of the stainless steel profiled wire for automotive windshield wipers in Example 5 is 573 N / mm². 2 It has an elongation of 20% and a glossy surface, free from defects such as black or yellow lines, scratches, cracks, folds, and peeling.

[0034] Comparative Example 1 This comparative example provides a stainless steel shaped wire for automotive windshield wipers. The only difference from Example 1 is that step S2 is not performed in the preparation process of this comparative example. Everything else is the same as in Example 1, and will not be repeated here.

[0035] Testing revealed that the tensile strength of this comparative example is 752 N / mm². 2 The elongation is 15%, and slight cracks appear on the surface.

[0036] Comparative Example 2 This comparative example provides a stainless steel shaped wire for automotive windshield wipers. The only difference from Example 1 is that step S3 is not performed in the preparation process of this comparative example. Everything else is the same as in Example 1, and will not be repeated here.

[0037] Testing revealed that the tensile strength of this comparative example is 784 N / mm². 2 The elongation rate is 11%, and slight cracks appear on the surface.

[0038] The inventors analyzed the following: The exemplary embodiment, through a synergistic process of graded cold working (S4 roughing and S5 fineing) and multi-stage online annealing (S4 and S5 two bright annealing processes), gradually releases processing stress, optimizes grain structure and dislocation distribution, avoids crack formation, and balances strength and toughness. Comparative Example 1, lacking roughing and a first annealing, suffers from unrelieved early work hardening and residual stress concentration. Subsequent cold working exacerbates internal defect accumulation, leading to cracks and significantly reduced plasticity. Comparative Example 2, omitting fineing and a second annealing, fails to further eliminate residual stress and refine grains, resulting in an imbalance between strength and ductility, and unrepairable surface defects. Both examples suffer from uneven internal structure, stress concentration, and insufficient surface integrity due to the absence of key processes, resulting in significantly inferior overall performance compared to the exemplary embodiment.

[0039] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A method for preparing a stainless steel profiled wire for automotive windshield wipers, characterized in that, The preparation method specifically includes the following steps: S1. Hot-rolled wire rod is subjected to rough drawing and one online bright annealing process to obtain stainless steel shaped wire. S2. The stainless steel shaped wire obtained in step S1 is subjected to fine drawing and secondary online bright annealing to obtain stainless steel shaped wire for automotive windshield wipers.

2. The preparation method according to claim 1, characterized in that, In step S1, the raw material for the stainless steel shaped wire is composed of the following components by mass percentage: C: ≤0.030%, 0.30%≤Si≤0.60%, 0.30%≤Mn≤0.60%, P: ≤0.030%, S: ≤0.020%, 0.20%≤Ni≤0.60%, 0.20%≤Cu≤0.60%, N: ≤0.40%, 18.00%≤Cr≤19.50%, 0.30%≤Nb≤0.70%, with the balance being Fe and unavoidable impurities.

3. The preparation method according to claim 1, characterized in that, In step S1, the diameter of the hot-rolled wire rod is 5.5 mm.

4. The preparation method according to claim 1, characterized in that, In step S1, the surface reduction rate of the coarse extraction process is 80-90%.

5. The preparation method according to claim 1, characterized in that, In step S1, the parameters for the first online bright annealing process are as follows: temperature is 700-900℃, and annealing speed is 3-9m / min.

6. The preparation method according to claim 1, characterized in that, In step S2, the surface reduction rate of the fine-drawing process is 70-85%.

7. The preparation method according to claim 1, characterized in that, In step S2, the parameters for the secondary online bright annealing process are as follows: temperature is 700-900℃, and annealing speed is 5-12m / min.

8. The preparation method according to claim 1, characterized in that, Both the primary and secondary online bright annealing processes are carried out in a protective atmosphere, which is a mixture of N2 and H2 gases with a flow rate of 1.2 ± 0.5 m³ / h and a volume ratio of 1:3.