阅读说明：本技术 一种高强韧弹簧钢盘条及其制备方法 (High-strength and high-toughness spring steel wire rod and preparation method thereof ) 是由 郑宏伟 刘文学 彭学艺 成建兵 江野 刘天强 王灿祥 于 2020-07-31 设计创作，主要内容包括：本发明公开了一种高强韧弹簧钢盘条及其制备方法,该钢盘条包括如下化学成分：C 0.55～0.65wt％,Si 1.45～1.65wt％,Mn 0.65～0.85wt％,P≤0.015wt％,S≤0.010wt％,Cr 0.80～1.00wt％,Cu≤0.10wt％,Mo≤0.04wt％,Ni 0.20～0.50wt％,V 0.05～0.10wt％,N≤0.006wt％,As≤0.015wt％,Sn≤0.010wt％,O≤0.0015wt％,H≤0.00015wt％,其余为Fe和不可避免的杂质,并提供该钢盘条的制备方法。热轧盘条经热处理后,抗拉强度≥2100MPa,断后伸长率≥10％,断面收缩率≥40％,具备优良的强度和塑性。(The invention discloses a high-strength and high-toughness spring steel wire rod and a preparation method thereof, wherein the steel wire rod comprises the following chemical components: 0.55 to 0.65 wt% of C, 1.45 to 1.65 wt% of Si, 0.65 to 0.85 wt% of Mn, less than or equal to 0.015 wt% of P, less than or equal to 0.010 wt% of S, 0.80 to 1.00 wt% of Cr, less than or equal to 0.10 wt% of Cu, less than or equal to 0.04 wt% of Mo, 0.20 to 0.50 wt% of Ni, 0.05 to 0.10 wt% of V, less than or equal to 0.006 wt% of N, less than or equal to 0.015 wt% of As, less than or equal to 0.010 wt% of Sn, less than or equal to 0.0015 wt% of O, less than or equal to 0.00015 wt% of H, and the balance. After the hot-rolled wire rod is subjected to heat treatment, the tensile strength is more than or equal to 2100MPa, the elongation after fracture is more than or equal to 10 percent, the reduction of area is more than or equal to 40 percent, and the hot-rolled wire rod has excellent strength and plasticity.)

1. The high-strength and high-toughness spring steel wire rod is characterized by comprising the following chemical components: 0.55 to 0.65 wt% of C, 1.45 to 1.65 wt% of Si, 0.65 to 0.85 wt% of Mn, less than or equal to 0.015 wt% of P, less than or equal to 0.010 wt% of S, 0.80 to 1.00 wt% of Cr, less than or equal to 0.10 wt% of Cu, less than or equal to 0.04 wt% of Mo, 0.20 to 0.50 wt% of Ni, 0.05 to 0.10 wt% of V, less than or equal to 0.006 wt% of N, less than or equal to 0.015 wt% of As, less than or equal to 0.010 wt% of Sn, less than or equal to 0.0015 wt% of O, less than or equal to 0..

2. The preparation method of the high-strength and high-toughness spring steel wire rod of claim 1 is characterized by comprising the following steps of: the method comprises the following steps of high-purity smelting, refining and deoxidizing, continuous casting, finishing, cogging and rolling, wherein 92-98% of molten iron is added in the high-purity smelting, the molten iron is subjected to desulfurization pretreatment, and the S content is required to be less than or equal to 0.020% after desulfurization.

3. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: before and during refining, the flow of argon is controlled to be 400-600L/min, and the flow of argon at the later refining stage is controlled to be 300-400L/min.

4. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: and Si deoxidation is adopted for deoxidation.

5. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: and the deoxidation selects low-aluminum silicon iron alloy.

6. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: the continuous casting drawing speed is 0.45-0.55m/min, the superheat degree of continuous casting is controlled at 15-35 ℃, the secondary cooling of the continuous casting is in a weak cooling mode, the specific water amount of the continuous casting is 0.20-0.30L/kg, the electromagnetic stirring of the continuous casting is 200-400 multiplied by 2A × Hz, and the light pressure of the continuous casting is static medium light pressure.

7. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: the cogging adopts a high-temperature diffusion cogging technology.

8. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 7, which is characterized by comprising the following steps of: the cogging technology of high-temperature diffusion is to perform high-temperature diffusion at the temperature of 1200-1250 ℃.

9. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: the finishing is that the grinding depth on the surface of the blank is more than or equal to 0.6 mm.

10. The preparation method of the high-strength high-toughness spring steel wire rod according to claim 2, which is characterized by comprising the following steps of: the temperature of a rolling soaking section is 980-1060 ℃, the rolling initial rolling temperature is 950-1000 ℃, the rolling final rolling temperature is 820-880 ℃, the rolling spinning temperature is 820-880 ℃, and the rolling cover entering temperature is 750-820 ℃.

Technical Field

The invention relates to a spring steel wire rod and a preparation method thereof, in particular to a high-strength and high-toughness spring steel wire rod and a preparation method thereof.

Background

With the rapid development of the transportation industry towards modernization and high speed and the vigorous implementation of energy-saving and emission-reducing policies, the requirement on light weight of automobiles is increasingly strong. An important way to realize the lightweight of automobiles is to adopt high-strength steel to produce automobile parts, and research and develop spring steel for automobiles with high strength, excellent anti-bouncing performance and anti-fatigue performance, which becomes an important field of the technical development of automobile materials.

At present, spring steel wire rods applied to automobile suspension springs mainly take 1800MPa grade and 1900MPa grade. The strength of the 55SiCr spring steel wire rod adopted by the existing automobile suspension spring after heat treatment reaches 2000MPa and reaches the performance limit of the product.

Disclosure of Invention

The purpose of the invention is as follows: the first purpose of the invention is to provide a high-strength and high-toughness spring steel wire rod with the tensile strength of more than or equal to 2100MPa, and the second purpose of the invention is to provide a preparation method of the high-strength and high-toughness spring steel wire rod.

The technical scheme is as follows: the invention relates to a high-strength and high-toughness spring steel wire rod, which comprises the following chemical components: 0.55 to 0.65 wt% of C, 1.45 to 1.65 wt% of Si, 0.65 to 0.85 wt% of Mn, less than or equal to 0.015 wt% of P, less than or equal to 0.010 wt% of S, 0.80 to 1.00 wt% of Cr, less than or equal to 0.10 wt% of Cu, less than or equal to 0.04 wt% of Mo, 0.20 to 0.50 wt% of Ni, 0.05 to 0.10 wt% of V, less than or equal to 0.006 wt% of N, less than or equal to 0.015 wt% of As, less than or equal to 0.010 wt% of Sn, less than or equal to 0.0015 wt% of O, less than or equal to 0..

In the invention, by adding a proper amount of V, Ni and properly increasing the Cr content, the strength of the material is improved on the premise of ensuring the plasticity, and the technical requirement of a 2100MPa grade high-toughness spring steel wire rod is met.

Meanwhile, the corrosion fatigue resistance is improved by adding Ni which can form a dense amorphous rust layer. Further, the S content is reduced to reduce the amount of MnS which becomes a starting point of cracking and reduces the fatigue resistance. The delayed fracture resistance is improved by increasing the content of V, and V has the effect of capturing hydrogen through precipitation of fine carbides, so that concentration of hydrogen to high-stress parts is prevented, and embrittlement is prevented.

The preparation method of the high-strength and high-toughness spring steel wire rod comprises the following steps of: the method comprises the following steps of high-purity melting, refining and deoxidizing, continuous casting, finishing, cogging and rolling, wherein more than 92-98% of molten iron is added in the high-purity melting, the molten iron is subjected to desulfurization pretreatment, and the S content is required to be less than or equal to 0.020% after desulfurization.

Before and during refining, the flow of argon is controlled to be 400-600L/min, and the flow of argon at the later refining stage is controlled to be 300-400L/min, so that the molten steel is prevented from being exposed for secondary oxidation, and impurities are promoted to float sufficiently.

And Si is used for deoxidation. Deoxidizing, selecting low-Al-Si-Fe alloy, and controlling Al in inclusions₂O₃The content of (a).

The continuous casting speed is 0.45-0.55m/min, the superheat degree of continuous casting is controlled at 15-35 ℃, the secondary cooling of the continuous casting is in a weak cooling mode, the specific water amount of the continuous casting is 0.20-0.30L/kg, the electromagnetic stirring of the continuous casting is 200-400 multiplied by 2A Hz, and the static medium light pressure is adopted under the light pressure of the continuous casting. The section of 320 multiplied by 420mm is adopted for continuous casting, and finally, the section of 320 multiplied by 420mm of a large square billet is adopted to be matched with proper continuous casting process parameters, so that the high-homogenization billet of the high-strength and high-toughness spring steel wire rod with the tensile strength of more than or equal to 2100MPa is obtained.

The cogging adopts a high-temperature diffusion cogging technology. The cogging technology of high-temperature diffusion is to perform high-temperature diffusion at the temperature of 1200-1250 ℃, so that the center segregation of the blank is reduced, and the uniformity of the material is improved.

Finishing is to polish the surface of the blank to a depth of more than or equal to 0.6 mm. The temperature of a rolling soaking section is 980-1060 ℃, the rolling starting temperature is 950-1000 ℃, the rolling finishing temperature is 820-880 ℃, the rolling spinning temperature is 820-880 ℃, and the rolling cover entering temperature is 750-820 ℃.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: the high-strength and high-toughness spring steel wire rod is excellent in strength and plasticity and suitable for designing and selecting ultra-lightweight passenger vehicle suspension springs, and after the hot-rolled wire rod is subjected to heat treatment, the tensile strength is more than or equal to 2100MPa, the elongation after fracture is more than or equal to 10%, and the reduction of area is more than or equal to 40%; expensive rare earth elements are not required to be added, the alloy system is simple to regulate and control, the manufacturing process of the high-strength and high-toughness automobile suspension spring steel wire rod is simple and easy to operate, and the batch production of the process is facilitated; rare earth elements such as Zr, Re and the like do not need to be added, and the addition amount of other microalloy elements is strictly controlled, so that the production cost of the automobile suspension spring steel wire rod with high fatigue life is ensured.

Drawings

FIG. 1 is a metallographic structure of a spring steel wire rod according to the present invention.

Detailed Description

The technical solution of the present invention is further illustrated by the following examples.