Production method of rare-earth atmosphere-corrosion-resistant 550MPa-grade welding wire steel

Abstract

The invention discloses a production method of rare earth atmosphere corrosion resistant 550MPa grade welding wire steel, which comprises the following steps: converter smelting, LF refining, small square billet continuous casting, rolling of a wire rod into a phi 5.5 mm steel wire rod, and wire drawing and copper plating of the steel wire rod into a phi 1.2 mm finished product welding wire. The production method has the key points that the addition of a precious metal nickel element is canceled, and meanwhile, the components and process design are optimized; the production cost is greatly reduced, and meanwhile, the performance requirements of the steel grade can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a production method of rare earth atmospheric corrosion resistant 550MPa grade welding wire steel. Background Art

[0002] Atmospheric corrosion resistant 550MPa grade welding wire steel is a weather-resistant welding steel, mainly used for welding of engineering vehicles, weather-resistant containers and bridge building structures.

[0003] In modern industrial manufacturing, as the requirements for atmospheric corrosion resistance of steel materials continue to increase, the corresponding welding materials also need to have higher atmospheric corrosion resistance to meet the application needs in engineering machinery, automobiles, mining machinery and other fields.

[0004] However, the same level of welding wires produced domestically generally have unstable corrosion resistance and low low-temperature impact toughness. Therefore, how to design a welding wire with good corrosion resistance and good low-temperature impact toughness has become an urgent problem to be solved. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a production method of rare earth atmospheric corrosion resistant 550MPa grade welding wire steel, which eliminates the addition of precious metal nickel elements, greatly reduces production costs, and at the same time can meet the performance requirements of this type of steel.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention discloses a method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel. During the steelmaking process, the carbon content, phosphorus content and sulfur content at the smelting end point are precisely controlled to ensure that the remaining components are mainly iron. During the refining process, ferrosilicon powder is used for deep deoxidation, and aluminum-containing deoxidizer is prohibited to ensure that the oxygen content in the molten steel is controlled below 20ppm, thereby promoting the optimal absorption rate of titanium.

[0008] The crystallizer electromagnetic stirring technology is used to effectively improve the cleanliness of molten steel, reduce the inclusion content, and provide high-quality ingots for subsequent hot-rolled wire rods;

[0009] The steel billet is heated to 1020-1060°C in a heating furnace;

[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;

[0011] The spinning temperature should be controlled between 830 and 860°C;

[0012] The wire rod is cooled by slow cooling, the cooling rate is controlled at ≤0.80℃ / s, and then online insulation cooling is performed at a rate of ≤0.12℃ / s to ≤120℃;

[0013] The chemical composition of the welding wire steel is as follows by mass percentage: C≤0.10%, Si≤0.15%, Mn1.55-1.75%, Cr 0.45-0.60%, Ti 0.04-0.08%, Cu 0.25-0.35%, RE addition amount is 30ppm, the balance is Fe and unavoidable impurities, P in the impurities is ≤0.020%, and S in the impurities is ≤0.020%.

[0014] Furthermore, the chemical composition of the welding wire steel is as follows by mass percentage: C 0.07%, Si 0.10%, Mn 1.57%, Cr 0.47%, Ti 0.05%, Cu 0.30%, RE 15ppm, and the remainder is Fe and unavoidable impurities, P in the impurities is 0.013%, and S in the impurities is 0.006%.

[0015] Furthermore, the chemical composition of the welding wire steel is, by mass percentage, C 0.07%, Si 0.12%, Mn 1.57%, Cr 0.49%, Ti 0.05%, Cu 0.29%, RE 16ppm, and the remainder is Fe and unavoidable impurities, P in the impurities is 0.010%, and S in the impurities is 0.005%.

[0016] Furthermore, the chemical composition of the welding wire steel is, by mass percentage, C 0.06%, Si 0.11%, Mn 1.59%, Cr 0.48%, Ti 0.06%, Cu 0.31%, RE 14ppm, and the remainder is Fe and unavoidable impurities, P in the impurities is 0.011%, and S in the impurities is 0.005%.

[0017] Furthermore, the weld impact absorption energy reaches more than 120J.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are:

[0019] Compared with conventional atmospheric corrosion resistant 550MPa grade welding wire steel, the invention eliminates the addition of precious metal nickel, greatly reducing production costs while meeting the performance requirements of the steel. For example, other domestic steel mills routinely add more than 0.5% nickel, while the invention replaces the addition of precious alloys by adding rare earth.

[0020] The invention is characterized by adopting a low-silicon component design, and the titanium and copper content is higher than that of similar welding wires, so its corrosion resistance is more excellent. At the same time, the low-silicon design is adopted, and its low-temperature impact toughness is also greatly improved. DETAILED DESCRIPTION

[0021] The main preparation process of atmospheric corrosion resistant 550MPa grade welding wire steel in this example is:

[0022] The process is converter smelting, LF refining, billet continuous casting, and wire rolling into Φ5.5mm wire rod, which is then drawn, copper plated, and made into Φ1.2mm finished welding wire.

[0023] The steelmaking process for producing high-strength welding wire steel wire rods begins with the smelting of molten iron, with the sulfur (S) content strictly controlled to be no more than 0.040%. The purification and alloying of the molten steel are ensured by adding deoxidizers and a series of alloying elements such as ferrosilicon, ferromanganese and ferrochrome to the ladle.

[0024] During the steelmaking process, the carbon (C) content, phosphorus (P) and sulfur (S) content at the end of smelting must be precisely controlled to ensure that the remaining components are mainly iron (Fe). During the refining process, ferrosilicon powder is used for deep deoxidation, and aluminum-containing deoxidizers are prohibited to ensure that the oxygen content in the molten steel is controlled below 20ppm to promote the optimal absorption rate of titanium (Ti).

[0025] The use of crystallizer electromagnetic stirring technology can effectively improve the cleanliness of molten steel, reduce the inclusion content, and provide high-quality ingots for subsequent hot-rolled wire rods.

[0026] The steel billet is heated to 1020-1060℃ in the heating furnace to ensure that the steel billet is evenly heated to the appropriate temperature, creating conditions for high-pressure water descaling.

[0027] 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 to ensure that the microstructure and mechanical properties of the wire rod meet the design requirements.

[0028] The spinning temperature should be controlled between 830 and 860°C. This step is crucial to the structure and performance of the final wire rod.

[0029] The wire rod is cooled by slow cooling, with the cooling rate controlled at ≤0.80℃ / s, and then cooled online at a rate of ≤0.12℃ / s to ≤120℃ to ensure the required microstructure and mechanical properties.

[0030] Table 1 Finished product composition (wt%, balance iron)

[0031] C Si Mn P S Cr Ti Cu RE Example 1 0.07 0.10 1.57 0.013 0.006 0.47 0.05 0.30 15ppm Example 2 0.07 0.12 1.58 0.010 0.005 0.49 0.05 0.29 16ppm Example 3 0.06 0.11 1.59 0.011 0.005 0.48 0.06 0.31 14ppm

[0032] Table 2 Weld impact test results

[0033]

[0034] It can be seen from the above table that the low-temperature impact performance of the weld of the rare earth solid welding wire of the present invention is significantly higher than that of the domestic solid welding wire of the same level.

[0035] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel, characterized in that: During the steelmaking process, the carbon content, phosphorus and sulfur content at the end of smelting must be accurately controlled to ensure that the remaining components are mainly iron; during the refining process, ferrosilicon powder is used for deep deoxidation, and aluminum-containing deoxidizers are prohibited to ensure that the oxygen content in the molten steel is controlled below 20ppm to promote the optimal absorption rate of titanium; The crystallizer electromagnetic stirring technology is used to effectively improve the cleanliness of molten steel, reduce the inclusion content, and provide high-quality ingots for subsequent hot-rolled wire rods; The steel billet is heated to 1020-1060°C in a heating furnace; 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; The wire rod is cooled by slow cooling, the cooling rate is controlled at ≤0.80℃ / s, and then online insulation cooling is performed at a rate of ≤0.12℃ / s to ≤120℃; The chemical composition of the welding wire steel is as follows by mass percentage: C≤0.10%, Si≤0.15%, Mn1.55-1.75%, Cr0.45-0.60%, Ti 0.04-0.08%, Cu 0.25-0.35%, RE addition amount is 30ppm, the balance is Fe and unavoidable impurities, P in the impurities is ≤0.020%, and S in the impurities is ≤0.020%.

2. The method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel according to claim 1, characterized in that: The chemical composition of the welding wire steel is as follows by mass percentage: C 0.07%, Si 0.10%, Mn 1.57%, Cr 0.47%, Ti 0.05%, Cu 0.30%, RE 15ppm, and the remainder is Fe and unavoidable impurities, P in the impurities is 0.013%, and S in the impurities is 0.006%.

3. The method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel according to claim 1, characterized in that: The chemical composition of the welding wire steel is as follows by mass percentage: C 0.07%, Si 0.12%, Mn 1.57%, Cr 0.49%, Ti 0.05%, Cu 0.29%, RE 16ppm, the remainder is Fe and unavoidable impurities, P in the impurities is 0.010%, and S in the impurities is 0.005%.

4. The method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel according to claim 1, characterized in that: The chemical composition of the welding wire steel is as follows by mass percentage: C 0.06%, Si 0.11%, Mn 1.59%, Cr 0.48%, Ti 0.06%, Cu 0.31%, RE 14ppm, and the remainder is Fe and unavoidable impurities, P in the impurities is 0.011%, and S in the impurities is 0.005%.

5. The method for producing rare earth atmospheric corrosion resistant 550MPa grade welding wire steel according to claim 1, characterized in that: The weld impact absorption energy is over 120J.

Images