Production method of low-alloy single-rolled steel plate for cold spinning machining

Abstract

The invention discloses a production method of a low-alloy single-rolled steel plate for cold spinning processing. The production method comprises the following steps: (1) designing components of a newly added blank; (2) in the continuous casting process, a slow pulling speed of 1.10-1.30 m / min and a weak electromagnetic stirring process are designed, the current is 160-180 A, and the frequency is 6-11 Hz; (3) a Q355 steel plate with the thickness specification of 20-30 mm is produced from a blank with the section of 150-220 mm, the heating temperature of the blank is adjusted to be 1200-1250 DEG C, the heating time is 0.8-1.6 min / mm, and the blank is heated evenly; and (4) the high rolling temperature is adopted, the secondary rolling temperature is smaller than or equal to 980 DEG C, the final rolling temperature is 800-900 DEG C, the self-tempering temperature is increased to 660-700 DEG C, and the high ductility can still be kept on the basis that the strength is improved. The method has the advantages that the strength performance and the ductility of the Q355-grade steel plate with the thickness specification of 20-30 mm are improved, the service life of a workpiece is prolonged, and the machining performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for producing a low-alloy single-rolled steel plate for cold spinning processing. Background Art

[0002] With the rapid development of the automobile industry and the increasing requirements of consumers for vehicle performance, cold spinning of car wheels, as an advanced manufacturing technology, plays an increasingly important role in modern manufacturing. It not only meets the needs of the automobile manufacturing industry for high-precision and high-quality parts, but also promotes the development of the automobile manufacturing industry in a more environmentally friendly and efficient direction. Among them, mining vehicles have higher requirements for the quality of wheels. The existing 20~30mm thick Q355 grade steel plates cannot take into account both strength and elongation, have limited deformation resistance and are not easy for customers to process and use. Figure 1 As shown, the service life is therefore shorter, which undoubtedly reduces the performance quality of the wheel hub and increases the processing cost. Summary of the invention

[0003] The purpose of the present invention is to solve the problems of low strength and elongation, short life and high processing cost of existing single-rolled steel plates, and to provide a production method of low-alloy single-rolled steel plates for cold spinning processing, which can improve the strength performance and elongation of Q355 grade steel plates with a thickness of 20~30mm, increase the service life of workpieces, and improve processing performance.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A method for producing a low alloy single rolled steel plate for cold spinning processing, specifically comprising: (1) Added blank composition design; (2) Continuous casting process parameter setting: The continuous casting process is designed with a slow casting speed of 1.10~1.30m / min and a weak electromagnetic stirring process, a current of 160~180A, and a frequency of 6~11Hz; (3) Heating parameter setting: Use 150~220mm cross-section billets to produce 20~30mm thick Q355 steel plates, adjust the billet heating temperature to 1200~1250℃ and the heating time to 0.8~1.6min / mm to ensure uniform heating of the billet; (4) Rolling parameter setting: Use a higher rolling temperature, second rolling ≤ 980℃, final rolling 800~900℃, and increase the red-return temperature to 660~700℃, so as to improve the strength while still maintaining a higher elongation.

[0005] Furthermore, in the step (1), the composition of the blank includes, by mass percentage, the following: C: 0.08-0.12, Mn: 1.40-1.60, P≤0.015, S≤0.005, Si: 0.1-0.3, Nb: 0.02-0.04, Cr: 0.1-0.2, and Ti: 0.005-0.02.

[0006] Furthermore, in the step (1), the blank composition, in terms of mass percentage, includes: C: 0.09, Mn: 1.46, P: 0.012, S: 0.003, Si: 0.21, Nb: 0.026, Cr: 0.16, Ti: 0.014.

[0007] Furthermore, in the step (2), the pulling speed is 1.1 m / min, the electromagnetic stirring process is used, the current is 180 A, and the frequency is 6 Hz.

[0008] Furthermore, in the step (3), a 220 mm cross-section billet is used, the heating temperature is 1230° C., and the heating time is 1.0 min / mm.

[0009] Furthermore, in the step (4), the finishing rolling temperature is 952°C, the final rolling temperature is 868°C, the water entry temperature is 804°C, and the red return temperature is 677°C.

[0010] In the technical solution of the present invention, by adopting high-temperature rolling, high water entry temperature process, and high red-returning temperature design, the cooling strength is guaranteed, the rapid cooling structure is reduced, the surface processing cracking is reduced, and the processing performance and strength performance are improved, ReH ≥ 400MPa, Rm ≥ 500MPa, the deformation resistance of the workpiece is improved, and the service life is increased; in addition, the elongation performance is also improved, A ≥ 25%, which is easy for customers to process and use, and reduces the processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a physical picture of a conventional Q355 grade steel plate in the prior art; Figure 2 This is a physical picture of a Q355 grade steel plate in an embodiment of the present invention; Figure 3 This is the metallographic structure diagram of the Q355 grade steel plate in the embodiment of the present invention. DETAILED DESCRIPTION Example

[0012] To make the present invention more clear, a method for producing a low-alloy single-rolled steel plate for cold spinning processing of the present invention is further described below in conjunction with the accompanying drawings. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0013] In this embodiment, taking the steel grade Q355B, 24.5*2400mm specification order as an example, its composition design is a new design scheme added in the following table:

[0014] (1) Continuous casting process: casting speed 1.1m / min, electromagnetic stirring process, current 180A, frequency 6Hz; (2) Rolling method: Use 220mm cross-section billet, heating steel tapping temperature is 1230℃, heating time is 1.0min / mm.

[0015] (3) The rolling parameters are shown in the following table. The high temperature rolling, high water entry temperature process and high red-return temperature design are adopted to ensure the cooling strength, reduce the rapid cooling structure, reduce the surface processing cracking, and improve the processing performance:

[0016] After adopting the method of the present invention, the metallographic structure diagram and the physical diagram of the low alloy single rolled steel plate are as follows: Figure 3 and Figure 2 The specific mechanical properties are shown in the following table:

[0017] The present invention redesigns the production method of Q355 grade steel plate to improve the strength performance and elongation of 20-30mm thick steel plate, thereby increasing the service life of the workpiece and improving the processing performance. The defective rate of the workpiece is reduced by 5%, the annual demand is about 5,000 tons, and the loss of defective products is about 1,500 yuan / ton. Annual benefit N = 5,000 tons / year * 5% * 1,500 yuan / ton = 375,000 yuan.

[0018] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A method for producing a low alloy single rolled steel plate for cold spinning, characterized in that: (1) Added blank composition design; (2) Continuous casting process parameter setting: The continuous casting process is designed with a slow casting speed of 1.10~1.30m / min and a weak electromagnetic stirring process, a current of 160~180A, and a frequency of 6~11Hz; (3) Heating parameter setting: Use 150~220mm cross-section billets to produce 20~30mm thick Q355 steel plates, adjust the billet heating temperature to 1200~1250℃ and the heating time to 0.8~1.6min / mm to ensure uniform heating of the billet; (4) Rolling parameter setting: Use a higher rolling temperature, second rolling ≤ 980℃, final rolling 800~900℃, and increase the red-return temperature to 660~700℃, so as to improve the strength while still maintaining a higher elongation.

2. The method for producing a low alloy single rolled steel sheet for cold spinning according to claim 1, characterized in that: In the step (1), the blank composition includes, by mass percentage, C: 0.08-0.12, Mn: 1.40-1.60, P≤0.015, S≤0.005, Si: 0.1-0.3, Nb: 0.02-0.04, Cr: 0.1-0.2, and Ti: 0.005-0.

02.

3. The method for producing a low alloy single rolled steel sheet for cold spinning according to claim 1, characterized in that: In the step (1), the composition of the blank includes, by mass percentage, C: 0.09, Mn: 1.46, P: 0.012, S: 0.003, Si: 0.21, Nb: 0.026, Cr: 0.16, and Ti: 0.

014.

4. The method for producing a low alloy single rolled steel sheet for cold spinning according to any one of claims 1 to 3, characterized in that: In the step (2), the pulling speed is 1.1 m / min, the electromagnetic stirring process is used, the current is 180 A, and the frequency is 6 Hz.

5. The method for producing a low alloy single rolled steel sheet for cold spinning according to any one of claims 1 to 3, characterized in that: In the step (3), a 220 mm cross-section billet is used, the heating temperature is 1230° C., and the heating time is 1.0 min / mm.

6. The method for producing a low alloy single rolled steel sheet for cold spinning according to any one of claims 1 to 3, characterized in that: In the step (4), the finishing rolling temperature is 952°C, the final rolling temperature is 868°C, the water entry temperature is 804°C, and the red-returning temperature is 677°C.

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