High-strength wear-resistant steel gas shielded welding wire and preparation method thereof

Abstract

The application discloses a kind of high-strength wear-resistant steel gas shielded welding wire and preparation method thereof, the chemical composition of the welding wire includes C:0.09-0.15%, Si:0.55-0.82%, Mn:2.30-2.85%, Ni:0.10-0.45%, Cr:0.02-0.06%, Nb:0.03-0.06% and the like;Its preparation method is: after raw materials are mixed, smelted by vacuum induction furnace, forged, hot-rolled, annealed to form wire rod steel, pickling removes wire rod steel surface oxide skin, after rough drawing, precision drawing, heat treatment, cleaning, copper plating is prepared after drying;The welding wire is applied to high-strength wear-resistant steel welding process for CO2 gas shielded welding, adopts three-pass welding process method;It can significantly improve the impact toughness of welded joint weld zone and heat affected zone, meets the welding requirement of high-strength wear-resistant steel, expands the application field of high-strength wear-resistant steel, and further promotes the development of new equipment manufacturing industry.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a high-strength wear-resistant steel gas shielded welding wire and its preparation method. Background Technology

[0002] Construction machinery is an important component of the equipment manufacturing industry, referring to equipment used in mining and various engineering construction projects, such as excavators, loaders, bulldozers, various cranes, and hydraulic supports for coal mines. With the rapid development of my country's economy, the expansion of construction and resource development has led to a surge in demand for construction machinery. The construction machinery industry has become one of the fastest-growing and most promising sectors in machinery manufacturing, resulting in the rapid development of wear-resistant steel. As construction machinery gradually develops towards high performance, lightweight, and large-scale applications, its outer surface directly contacts materials such as sand and ore, bearing extremely complex loads. It is subjected not only to strong impacts and severe wear but also to periodic alternations. Therefore, the steel used must possess not only general strength and toughness but also wear resistance, impact resistance, fatigue resistance, and good weldability. With the increasingly widespread application of high-strength wear-resistant steel, which has high strength and good wear resistance, the requirements for welding wire used in welding this type of steel are also becoming higher. However, there are very few welding wires on the market that can meet the welding requirements of high-strength wear-resistant steel. In actual production, lower-grade welding wires are often used for welding. The performance of the steel structure after cladding with these welding wires cannot match that of high-strength wear-resistant steel in terms of hardness, strength, or wear resistance. This results in poor impact toughness of the welded joint, which cannot meet the requirements for welding high-strength wear-resistant steel. Therefore, it is urgent to develop a welding wire material for welding high-strength wear-resistant steel to further promote the application and promotion of high-strength wear-resistant steel. Summary of the Invention

[0003] In order to overcome the defects in the prior art, the present invention provides a gas shielded welding wire for high-strength wear-resistant steel and its preparation method, which is suitable for multi-layer and multi-pass welding of high-strength wear-resistant steel. The weld formation is beautiful and the obtained weld joint has excellent impact toughness.

[0004] To achieve the above-mentioned objective, this invention provides a high-strength wear-resistant steel gas-shielded welding wire. The chemical composition of the welding wire, by mass percentage, includes C: 0.09–0.15%, Si: 0.55–0.82%, Mn: 2.30–2.85%, Ni: 0.10–0.45%, Cr: 0.02–0.06%, S≤0.03%, P≤0.03%, Nb: 0.03–0.06%, B: 0.005–0.025%, O+N: 0.001–0.006%, with the balance being Fe and unavoidable impurities.

[0005] Carbon (C) is the most important alloying element in microalloyed weld metal. Increasing the C content can significantly improve the strength and hardness of the weld. However, excessively high C content can make the weld brittle, reduce its impact toughness, and increase the likelihood of welding cracks. Therefore, the C content is limited to the range of 0.09% to 0.15%.

[0006] Si plays a deoxidizing role in weld metal. It can prevent the combination of Fe and O and reduce FeO in the weld pool. Excessive Si content will cause SiO2 particles to be generated in the weld. These particles are difficult to dissolve and do not easily float out of the weld pool, thus reducing the quality of the weld joint. Therefore, the Si content is limited to the range of 0.55% to 0.82%.

[0007] Mn also plays a deoxidizing role in welds. Combined with Si, it can form MnO·SiO2 composite silicates, which have low melting points and low densities. These silicates agglomerate into large slag masses in the molten pool and easily float to the surface. Furthermore, Mn is an important hardenability element, contributing to solid solution strengthening. Excessive Mn content negatively impacts the toughness of welded joints; therefore, the Mn content is limited to the range of 2.30–2.85%.

[0008] Ni is an important element for ensuring the low-temperature toughness of weld metal. It can increase hardenability, expand the austenite region, and improve weld toughness. In addition, it can significantly improve the corrosion resistance of weld. However, excessive Ni content can easily lead to stress corrosion cracking in weld. Therefore, the Ni content should be controlled within the range of 0.10% to 0.45%.

[0009] Cr can play a role in solid solution strengthening in welds, increasing the hardness of weld metal, but the reduction in ductility and toughness is not significant. Cr can improve the weld's resistance to oxidizing media corrosion. However, excessive Cr content will reduce the thermal conductivity of weld metal and easily produce carbon and oxides. Therefore, the Cr content is limited to the range of 0.02% to 0.06%.

[0010] S readily combines with Fe to form FeS, significantly reducing weld toughness. The hot brittleness of S also easily leads to hot cracking during welding. In addition, S readily combines with Mn to form insoluble MnS, which is distributed in granular form within the grains, reducing the overall performance of the weld. Therefore, the S content is limited to below 0.03%.

[0011] P can dissolve completely in ferrite, increasing the strength and hardness of steel but decreasing its ductility and toughness. The effect is more severe at low temperatures, easily causing welding cracks. Therefore, the P content is limited to below 0.03%.

[0012] Nitrogen (Nb) can improve both the strength and toughness of welds, and also has a positive effect on their oxidation resistance and corrosion resistance. However, excessive Nb content will generate a large amount of carbonitrides, reducing the brittleness of the weld. Therefore, the Nb content is limited to the range of 0.03% to 0.06%.

[0013] In welds, boron (B) mainly plays a role in refining grain size. However, excessively high B content can increase weld brittleness and reduce toughness. Therefore, the B content is limited to the range of 0.005% to 0.025%.

[0014] O+N: O and N elements are harmful elements in welds. They easily combine with other alloying elements, and the resulting compounds are generally brittle, affecting the toughness of the weld. Therefore, the combined content of O and N elements is limited to the range of 0.001 to 0.006%.

[0015] A method for preparing the above-mentioned high-strength wear-resistant steel gas shielded welding wire, the method comprising the following steps:

[0016] ① Prepare the materials according to the chemical composition requirements of the welding wire, and mix all the raw materials evenly.

[0017] ②The raw materials mixed in step ① are smelted in a vacuum induction furnace at a temperature range of 1500±20℃, and then processed into wire rod steel through forging, hot rolling and annealing processes; the annealing temperature is 670±20℃ and the annealing time is 2-3h.

[0018] ③ Pickling removes the oxide scale from the surface of the wire rod steel produced in step ②.

[0019] ④ The wire rod steel obtained in step ③ is rough drawn and fine drawn into welding wire with a diameter of 0.8-1.5mm.

[0020] ⑤ The welding wire obtained in step ④ is heat-treated, cleaned, and dried until the surface is free of contamination.

[0021] ⑥ Copper plating is performed on the welding wire obtained in step ⑤, with a copper plating thickness of 0.10-0.35μm.

[0022] ⑦ Wrap and package to obtain the finished product.

[0023] An application of the aforementioned welding wire in the welding of high-strength wear-resistant steel, wherein the welding is CO2 gas shielded welding, and the welding process uses the aforementioned welding wire for three passes; wherein, the first pass welding process is as follows: welding current: 140-160A, welding voltage: 18-19V, welding speed: 8-10cm / min; the second pass welding process is as follows: welding current: 170-190A, welding voltage: 19.5-21.0V, welding speed: 20-24cm / min; the third pass welding process is as follows: welding current: 150-170A, welding voltage: 22.5-24.0V, welding speed: 13-15cm / min. Before each pass, the weld seam of the previous pass needs to be ground and cleaned until the weld surface is clean and free of weld slag, and the interpass temperature is controlled at 140-230℃.

[0024] The composition of the high-strength wear-resistant steel used in the above welding is as follows: C: 0.13–0.18%, Si: 0.18–0.20%, Mn: 1.30–1.90%, Ni: 0.15–0.35%, S: ≤0.03%, P: ≤0.04%, Nb: 0.02–0.05%, Mo: 0.10–0.35%, Als: 0.015–0.035%, Ti: 0.35–0.55%, with the balance being Fe and unavoidable impurities. The high-strength wear-resistant steel has a thickness of 8–12 mm, a tensile strength of 680–760 MPa, and a yield strength of 540–580 MPa.

[0025] During welding, the high-strength wear-resistant steel welding test plate is processed into a V-shaped bevel with a 30° angle on one side, and the surface to be welded is cleaned and ground. Before each welding pass, the weld of the previous pass needs to be ground and cleaned until the weld surface is clean and free of weld slag. The interpass temperature is controlled at 140-230℃.

[0026] Compared with the prior art, the beneficial effects of the present invention are: welding high-strength wear-resistant steel according to the above-mentioned welding wire composition and welding process can significantly improve the impact toughness of the weld zone and heat-affected zone of the weld joint. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but this does not limit the invention in any way. To avoid redundancy, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and the methods used are all conventional methods unless otherwise specified. The test standard for the impact performance of welded joints is GB / T 229-2020 Metallic Materials Charpy Pendulum Impact Test Method.

[0028] Example

[0029] A gas shielded welding wire for high-strength wear-resistant steel and its preparation method are disclosed. The finished welding wire is produced according to the composition and process in Table 1. The high-strength wear-resistant steel is welded using carbon dioxide gas shielded welding according to the welding process in Table 2. The impact performance of the weld area is tested at room temperature, and the results are shown in Table 3.

[0030] Table 1 Chemical composition and preparation method of welding wire

[0031]

[0032]

[0033] Table 2 Welding Process

[0034] example Example 1 Example 2 Comparative Example 1 Comparative Example 2 One-pass welding current / A 150 155 240 256 One-pass welding voltage / V 18 19 20 21 Welding speed per pass (cm / min) 9 10 12.1 11.5 Second pass welding current / A 180 190 235 220 Second pass welding voltage / V 20 21 22 18 Second pass welding speed (cm / min) 22 23 14.6 13.5 Three-pass welding current / A 160 170 Three-pass welding voltage / V 23 24 Three-pass welding speed (cm / min) 14 15 Interlayer temperature / °C 180 200 150 200

[0035] Table 3 Impact Performance of High-Strength Wear-Resistant Steel Welded Joints

[0036] example Example 1 Example 2 Comparative Example 1 Comparative Example 2 Impact energy in weld zone / J 93 106 42 53 Impact energy of heat-affected zone / J 98 102 56 61

[0037] The welding wire composition and welding process described in this invention can effectively control the microstructure and grain size of the welded joint, thereby improving the impact performance of the welded joint by more than 40% and significantly improving its service performance.

[0038] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A high-strength wear-resistant steel gas shielded welding wire, characterized in that, The chemical composition of the welding wire, by mass percentage, includes C: 0.09%–0.15%, Si: 0.55%–0.82%, Mn: 2.30%–2.85%, Ni: 0.10%–0.45%, Cr: 0.02%–0.06%, S≤0.03%, P≤0.03%, Nb: 0.03%–0.06%, B: 0.005%–0.025%, O+N: 0.001%–0.006%, with the balance being Fe and unavoidable impurities; The welding wire is prepared by the following method: ① Prepare the materials according to the chemical composition requirements of the welding wire, and mix all the raw materials evenly; ②The raw materials mixed in step ① are smelted in a vacuum induction furnace at a temperature range of 1500±20℃, and then processed into wire rod steel through forging, hot rolling and annealing processes; the annealing temperature is 670±20℃ and the annealing time is 2-3h. ③ Pickling removes the oxide scale from the surface of the wire rod produced in step ②; ④ The wire rod obtained in step ③ is rough drawn and fine drawn into welding wire with a diameter of 0.8-1.5mm; ⑤ The welding wire obtained in step ④ is heat-treated, cleaned, and dried until the surface is free of contamination; ⑥ Copper plating is performed on the welding wire obtained in step ⑤, with a copper plating thickness of 0.10-0.35μm; ⑦ Wrap and package to obtain the finished product.

2. The application of the welding wire according to claim 1 in the welding of high-strength wear-resistant steel, characterized in that, The welding is CO2 gas shielded welding, and the welding process uses the above-mentioned welding wire to perform three welding passes.

3. The application according to claim 2, characterized in that, The welding process for a single pass is as follows: welding current: 140-160A, welding voltage: 18-19V, welding speed: 8-10cm / min.

4. The application according to claim 2, characterized in that, The two-pass welding process is as follows: welding current: 170-190A, welding voltage: 19.5-21.0V, welding speed: 20-24cm / min.

5. The application according to claim 2, characterized in that, The three-pass welding process is as follows: welding current: 150-170A, welding voltage: 22.5-24.0V, welding speed: 13-15cm / min.

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