Production method of wire rod for rare earth prestressed steel bar

Abstract

The invention discloses a production method of a wire rod for a rare earth prestressed steel bar, which is characterized in that the wire rod comprises the following chemical components in percentage by mass: 0.29-0.32% of C, 0.60-0.70% of Si, 1.10-1.30% of Mn, 10-30 ppm of RE and the balance of Fe and inevitable impurities, P in the impurities is less than or equal to 0.040%, and S in the impurities is less than or equal to 0.040%; the invention further discloses specific production and process parameters of the composite material. According to the production method of the wire rod for the rare earth prestressed steel bar, the wire rod for the rare earth prestressed steel bar with high strength and good corrosion resistance is produced through a specific technological process and a rare earth element adding mode.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material processing, and in particular relates to a production method of a wire rod for rare earth prestressed steel bars. Background Art

[0002] Prestressed steel rods are widely used in engineering applications such as buildings, bridges, and tunnels, where their performance directly impacts the safety and durability of these structures. Traditional methods for producing prestressed steel rods suffer from low strength and poor corrosion resistance. The addition of rare earth elements (REs) can significantly improve the overall performance of steel, but how to uniformly incorporate these elements into prestressed steel rods while ensuring both high strength and excellent corrosion resistance remains a pressing technical challenge. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for producing rare earth prestressed steel bar wire rod, which produces high-strength and good corrosion-resistant rare earth prestressed steel bar wire rod through a specific process flow and a method of adding rare earth elements.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for producing a wire rod for rare earth prestressed steel bars. The chemical composition of the wire rod is, by mass percentage, C 0.29-0.32%, Si 0.60-0.70%, Mn 1.10-1.30%, RE 10-30ppm, and the balance is Fe and unavoidable impurities, wherein P in the impurities is ≤0.040%, and S in the impurities is ≤0.040%. The production method comprises:

[0006] Converter smelting: add deoxidizer silicon calcium barium 0.7-0.9kg / t at the time of tapping to ensure high carbon steel, that is, steel C ≥ 0.30%; the recarburizer should be low nitrogen recarburizer to reduce the adverse effect of nitrogen content on steel properties.

[0007] Refining treatment: Use medium-low basicity refining slag system, control binary basicity within the range of r=1-2.5, add rare earth alloy for alloying treatment under good deoxidation and desulfurization conditions of molten steel, feed Ca-Si line 150m / furnace at the end of LF refining, and carry out soft blowing treatment for ≥15 minutes;

[0008] Continuous casting process: 150mm small square billets are used for casting, and the superheat is kept constant within the range of 15-25°C. The continuous casting speed is controlled at 2.1m / min. Electromagnetic stirring of the mold and end-stage electromagnetic stirring are used during the continuous casting process to improve the macrostructure of the billet and reduce the segregation index.

[0009] Rolling: The rolling heating furnace should be controlled to have a neutral atmosphere, with a heating time of 90 to 110 minutes and a soaking zone temperature of 1200°C to promote high-temperature diffusion and reduce segregation index; the high-pressure water descaling pressure should be ≥12MPa and the descaling rate should be ≥95% to ensure the surface quality of the steel;

[0010] The starting temperature of rough rolling should be controlled between 1000 and 1040°C, while the ending temperature of finishing rolling should be controlled between 1020 and 1050°C; the spinning temperature should be controlled between 830 and 860°C.

[0011] Furthermore, 0.8 kg / t of deoxidizer silicon calcium barium is added at one time during steel tapping.

[0012] Furthermore, its chemical composition, calculated by mass percentage, is: C 0.30%, Si 0.67%, Mn 1.23%, RE 16 ppm, and the balance is Fe and unavoidable impurities, wherein P in the impurities is 0.015%, and S in the impurities is 0.012%.

[0013] Furthermore, its chemical composition, calculated by mass percentage, is: C 0.31%, Si 0.68%, Mn 1.24%, RE 15 ppm, and the balance is Fe and unavoidable impurities, P of the impurities is 0.022%, and S of the impurities is 0.022%.

[0014] Furthermore, its chemical composition, calculated by mass percentage, is: C 0.31%, Si 0.65%, Mn 1.23%, RE 15 ppm, and the balance is Fe and unavoidable impurities, wherein P among the impurities is 0.023%, and S among the impurities is 0.015%.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects:

[0016] The invention adopts a specific process flow and a method of adding rare earth elements to produce a rare earth prestressed steel bar wire rod with high strength and good corrosion resistance, meeting the high performance requirements of the engineering field for prestressed steel bars. DETAILED DESCRIPTION

[0018] Three heats of steel were produced in industrial trial production, with the following specific controls:

[0019] Table 1 Finished product composition (wt%, balance iron)

[0020] C Si Mn RE(ppm) P S Example 1 0.30 0.67 1.23 16 0.015 0.012 Example 2 0.31 0.68 1.24 15 0.022 0.022 Example 3 0.31 0.65 1.23 15 0.023 0.015

[0021] The mechanical properties of the wire rods of the above three embodiments were tested, and the test results are listed in Table 2:

[0022] Table 2 Mechanical properties test

[0023]

[0024] As can be seen from Table 2, all indicators of the rare earth prestressed steel bars produced by the present invention meet the standard requirements and can meet the needs of users.

[0025] The invention adopts a specific process flow and a method of adding rare earth elements to produce a rare earth prestressed steel bar wire rod with high strength and good corrosion resistance, meeting the high performance requirements of the engineering field for prestressed steel bars.

[0026] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for producing a wire rod for rare earth prestressed steel bars, characterized in that: Its chemical composition is as follows: C 0.29-0.32%, Si 0.60-0.70%, Mn 1.10-1.30%, RE 10-30ppm, the remainder is Fe and unavoidable impurities, P in the impurities is ≤0.040%, S in the impurities is ≤0.040%; its production method comprises: Converter smelting: add deoxidizer silicon calcium barium 0.7-0.9kg / t at one time when tapping steel to ensure high carbon steel tapping, that is, steel tapping C ≥ 0.30%; low nitrogen recarburizer should be selected to reduce the adverse effect of nitrogen content on steel performance Refining treatment: Use medium and low basicity refining slag system, control binary basicity within the range of r=1-2.5, add rare earth alloy for alloying treatment under good conditions of molten steel deoxidation and desulfurization, feed Ca-Si line 150m / furnace at the end of LF refining, and perform soft blowing time ≥15 minutes; Continuous casting process: 150mm small square billets are used for casting, and constant superheat casting is guaranteed, which is controlled within the range of 15-25°C; the continuous casting speed is controlled at 2.1m / min, and crystallizer electromagnetic stirring and end electromagnetic stirring are used during the continuous casting process to improve the macrostructure of the billet and reduce the segregation index; Rolling: The rolling heating furnace should be controlled in a neutral atmosphere, the heating time should be 90 to 110 minutes, and the soaking section temperature should be controlled at 1200°C to promote high-temperature diffusion and reduce the segregation index; the high-pressure water descaling pressure should be ≥12MPa, and the descaling rate should be ≥95% to ensure the surface quality of the steel; The starting temperature of rough rolling should be controlled between 1000 and 1040°C, while the ending temperature of finishing rolling should be controlled between 1020 and 1050°C; the spinning temperature should be controlled between 830 and 860°C.

2. The method for producing a wire rod for rare earth prestressed steel bars according to claim 1, characterized in that: When tapping steel, add 0.8kg / t of deoxidizer silicon, calcium and barium at one time.

3. The method for producing a wire rod for rare earth prestressed steel bars according to claim 1, characterized in that: The chemical composition thereof is as follows by mass percentage: C 0.30%, Si 0.67%, Mn 1.23%, RE 16ppm, and the remainder is Fe and unavoidable impurities, of which P is 0.015% and S is 0.012%.

4. The method for producing a wire rod for rare earth prestressed steel bars according to claim 1, characterized in that: The chemical composition thereof is as follows by mass percentage: C 0.31%, Si 0.68%, Mn 1.24%, RE 15 ppm, and the remainder is Fe and unavoidable impurities, of which P is 0.022% and S is 0.022%.

5. The method for producing a wire rod for rare earth prestressed steel bars according to claim 1, characterized in that: The chemical composition thereof is as follows by mass percentage: C 0.31%, Si 0.65%, Mn 1.23%, RE 15 ppm, and the remainder is Fe and unavoidable impurities, of which P is 0.023% and S is 0.015%.

Images