1000MPa-grade high-strength high-toughness solid copper-plating-free welding wire, preparation method thereof and large-heat-input argon-rich mixed gas shielded welding method

Abstract

The invention discloses a 1000MPa-grade high-strength and high-toughness solid copper-plating-free welding wire, a preparation method thereof and a large-heat-input argon-rich mixed gas shielded welding method. The invention belongs to the technical field of welding. The problems that during large heat input welding, a weld joint structure of a common welding wire is thick and large, the strength and toughness of a weld joint are reduced, and a welding wire and a welding technology matched with 1000MPa-grade high-strength steel do not exist are solved. The welding wire is prepared by regulating and controlling the components of the welding wire and adopting the vacuum induction furnace smelting and the roller die and eye film drawing technology, the chemical components of the welding wire are more accurately controlled, the higher wire feeding performance is guaranteed, and by means of the large-heat-input argon-rich mixed gas shielded welding method matched with the welding wire, the welding quality is improved. And the high wire feeding speed and the welding joint performance during large heat input welding wire are better facilitated. Therefore, when the low-alloy high-strength steel plate is welded, the welding wire and the welding technology are utilized, the welding work can be rapidly and efficiently completed by adopting large heat input, and it is guaranteed that the welding seam performance is good.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and specifically relates to a 1000MPa-grade high-strength and high-toughness solid copper-free welding wire and a preparation method thereof, and a high-heat-input argon-rich mixed gas shielded welding method. Background Art

[0002] In today's industrial field, the steel structure manufacturing industry is in a process of rapid development. This development trend has put forward higher and higher requirements on the efficiency of welding work and the quality of welds. High heat input welding technology has high deposition efficiency, can quickly complete welding work, and has excellent weld quality. In addition, this technology can save energy and reduce emissions, is easy to operate, and is easy to automate. Therefore, its application scope in actual production is gradually expanding.

[0003] However, in the case of high heat input welding, the weld structure of ordinary welding wire will become relatively coarse, resulting in a decrease in the strength and toughness of the weld, which in turn makes the weld prone to cracking. Based on this, when developing steel plates suitable for high heat energy welding, it is necessary to develop corresponding welding wires. Q1100 steel plates have been put into practical use in the field of engineering machinery, but due to the lack of welding wire materials that match their strength and toughness, most companies can only choose to use welding materials with lower strength when performing welding operations, and use welding methods with small heat input to make up for the lack of welding material strength. This approach not only has low deposition efficiency and slow welding speed, but also causes waste in energy utilization. With the continuous development of the major hydropower equipment manufacturing industry, medium and thick plates or large thick plates are mostly used in the construction of hydropower projects. The use of high heat input welding methods can significantly improve production efficiency. Therefore, high-strength and toughness welding wires have become an inevitable trend in the development of hydropower steel welding. At present, a certain amount of usage experience has been accumulated for 1000MPa grade low-alloy high-strength steel. In this case, it is necessary and urgent to develop corresponding domestic low-alloy high-strength steel welding wire and corresponding welding process. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of decreased weld strength and toughness of ordinary welding wires during high heat input welding, and the lack of welding wires and welding technology that match 1000MPa grade low-alloy high-strength steel. The present invention provides a 1000MPa grade high-strength and high-toughness solid copper-free welding wire and a preparation method thereof, and a high heat input argon-rich mixed gas shielded welding method.

[0005] The technical solution of the present invention is as follows:

[0006] One of the purposes of the present invention is to provide a 1000MPa grade high-strength and high-toughness solid copper-free welding wire, the chemical composition of the welding wire comprising by weight percentage: C 0.08-0.14%, Mn 1.60-2.00%, Si 0.50-0.80%, S0.030-0.080%, P≤0.008%, Ni 2.50-4.0%, Cr 0.40-1.0%, Mo 0.40-1.0%, Ti0.05-0.20%, V 0.005-0.02%, Cu 0.10-0.50%, Al 0.015-0.05%, and the balance being Fe and unavoidable impurities.

[0007] It is further defined that the chemical composition of the welding wire includes, by weight percentage: C 0.08-0.12%, Mn 1.60-1.90%, Si 0.50-0.70%, S 0.030-0.080%, P≤0.006%, Ni 3.00-3.7%, Cr 0.50-0.9%, Mo 0.60-0.90%, Ti 0.05-0.20%, V 0.005-0.02%, Cu 0.15-0.40%, Al0.015-0.05%, and the balance is Fe and unavoidable impurities.

[0008] It is further defined that the unavoidable impurities are Sn<0.004%, As<0.001%, and Pb<0.001%.

[0009] The second object of the present invention is to provide a method for preparing a 1000MPa grade high-strength and high-toughness solid copper-free welding wire, the method comprising:

[0010] S1: placing the welding wire raw materials into a vacuum induction furnace in sequence for smelting, pouring steel ingots, blanking and rolling in a rolling mill to obtain wire rods;

[0011] S2: After mechanical shelling, straightening and belt grinding, the wire rod is directly drawn into a three-roller die, and a total of 12 continuous drawing steps are performed to obtain the finished product;

[0012] S3: The finished product is cleaned online, the surface is coated with an anti-rust coating, and the densely packed layers are wound on a coil to obtain the welding wire.

[0013] It is further defined that the wire rod diameter in S1 is Φ5.5 mm.

[0014] It is further defined that the first 10 of the 12 continuous drawing passes in S2 are roller dies, and the last 2 are eye dies.

[0015] It is further defined that the diameter of the finished product in S2 is Φ1.18 mm.

[0016] The third object of the present invention is to provide a 1000MPa grade high strength and high toughness solid copper-free welding wire for use in high heat input argon-rich mixed gas shielded welding.

[0017] The fourth object of the present invention is to provide a method for shielded welding with argon-rich mixed gas suitable for large heat input, which uses the above-mentioned welding wire, and the volume fraction of the argon-rich mixed gas in the welding method is 80-95% Ar+5-20% CO2.

[0018] It is further defined that the volume fraction of the argon-rich mixed gas is 90% Ar+10% CO2.

[0019] It is further defined that the flow rate of the argon-rich mixed gas is 20 L / min.

[0020] It is further defined that the welding parameters of the welding method are: welding current 230-300A, welding voltage 25-31V, welding speed 120-420cm / min, and interpass temperature 135-175°C.

[0021] The fifth object of the present invention is to provide an application of the above-mentioned welding method in the welding of low-alloy high-strength steel plates with a weld tensile strength of 1000-1100Mpa.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention is applicable to welding technology with large heat input. Under the condition of welding heat input of 10 to 40 kJ / cm, the tensile strength of the deposited metal can reach 1000 to 1100 MPa, and it has excellent low-temperature impact toughness. In addition, the weld surface is bright, the weld bead is beautifully formed, and there are few spatters and smoke.

[0024] (2) The present invention uses a vacuum induction furnace smelting method to smelt molten iron when preparing welding wire, realizes the smelting of metal alloys in a vacuum atmosphere, and adopts the electromagnetic induction principle to form eddy currents in the smelted metal alloy to generate heat for heating and smelting. Through precise control, various impurities mixed into the product by the production raw materials are accurately removed. The vacuum characteristics of the vacuum induction furnace and the configuration of the vacuum induction furnace are used for precise deoxidation, so that the cleanliness of the raw materials used for the 1000MPa high-strength steel gas shielded welding wire is further improved, and the chemical composition of the welding wire can also be more accurately adjusted and controlled.

[0025] (3) The roller die drawing technology used in the present invention does not require pickling, boronizing, annealing and softening, and other process steps that damage the welding material. It only needs to control the cold plastic deformation process of the welding material to increase or decrease the yield strength and tensile strength of the welding material, thereby obtaining a welding wire with high yield strength and uniformity and stability. The last two eye mask drawing steps used in the present invention can make the welding wire have higher surface quality and wire feeding performance, which is more conducive to high wire feeding speed when the welding wire has large heat input. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of welding grooves of Examples 1-3 and Comparative Example 1;

[0027] Figure 2 The tensile strength of Examples 1-3 and Comparative Example 1 under different welding heat inputs;

[0028] Figure 3 The impact absorption energy at -40°C of Examples 1-3 and Comparative Example 1 under different welding heat inputs. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0031] The wire rod steel used in the following examples is made by vacuum induction furnace smelting. The process flow of solid welding wire is as follows: 5.5mm diameter wire rod, mechanical shelling, straightening, belt grinding, and then directly entering the three-roller die for drawing, cleaning, anti-rust coating, dense layer winding, and packaging.

[0032] When welding, use a welding machine trolley to fix the welding gun to ensure stable welding heat input.

[0033] Embodiment 1:

[0034] Welding wire diameter: 1.2mm. The chemical composition of the welding wire material is C 0.09%, Si 0.55%, Mn1.9%, Cr 0.82%, Ni 3.55%, Mo 0.65%, Ti 0.15%, Cu 0.35%, V 0.015%, S0.056%, P 0.0029%, Al 0.032% by weight, and the balance is Fe and unavoidable impurities.

[0035] Preparation of welding wire: The welding wire raw materials are sequentially put into a vacuum induction furnace for smelting, pouring steel ingots, blanking and rolling on a rolling mill to obtain a wire rod with a diameter of Ф5.5mm; the wire rod is directly drawn into a three-roller die after mechanical shelling, straightening and belt grinding, and undergoes 12 continuous drawing passes, with the first 10 passes being the roller die and the last 2 passes being the eye die. The diameter of the finished product is Ф1.18mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0036] The welding method of the deposited metal in this embodiment is carried out in accordance with the provisions of GB / T 8110-2008. The deposited metal test uses a Q345 steel plate with a low alloy content as a deposited test plate. The test plate thickness is 20 mm, and a single-sided 22.5° groove is machined. Figure 1 Test Example The impact property test of the weld metal of the isolation layer welded by the welding wire on the groove surface and the backing plate surface is carried out in accordance with the provisions of GB / T2650-2022, and the tensile property test of the weld metal is carried out in accordance with the provisions of GB / T 2652-2022.

[0037] This embodiment adopts argon-rich (90% Ar+10% CO2) shielding gas welding with a gas flow rate of 20 L / min. For detailed welding parameters, see Table 1.

[0038] Embodiment 2:

[0039] Wire diameter: 1.2mm. The chemical composition weight percentage of the welding wire material is C 0.095%, Si 0.53%, Mn 1.8%, Cr 0.78%, Ni 3.4%, Mo 0.75%, Ti 0.14%, Cu 0.36%, V 0.018%, S0.057%, P 0.0042%, Al 0.03%, and the balance is Fe and unavoidable impurities.

[0040] Preparation of welding wire: The welding wire raw materials are sequentially put into a vacuum induction furnace for smelting, pouring steel ingots, blanking and rolling on a rolling mill to obtain a wire rod with a diameter of Ф5.5mm; the wire rod is directly drawn into a three-roller die after mechanical shelling, straightening and belt grinding, and undergoes 12 continuous drawing passes, with the first 10 passes being the roller die and the last 2 passes being the eye die. The diameter of the finished product is Ф1.18mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0041] The welding method of the deposited metal in this embodiment is carried out in accordance with the provisions of GB / T 8110-2008. The deposited metal test uses a Q345 steel plate with a low alloy content as a deposited test plate. The test plate thickness is 20 mm, and a single-sided 22.5° groove is machined. Figure 1Test Example The welding wire welds the isolation layer on the groove surface and the backing plate surface, and the weld metal impact performance test is carried out in accordance with GB / T2650-2022, and the weld metal tensile performance test is carried out in accordance with GB / T 2652-2022.

[0042] This embodiment adopts argon-rich (90% Ar+10% CO2) shielding gas welding with a gas flow rate of 20 L / min. For detailed welding parameters, see Table 1.

[0043] Embodiment 3:

[0044] Welding wire diameter: 1.2mm. The chemical composition of the welding wire material is C 0.11%, Si 0.53%, Mn1.75%, Cr 0.65%, Ni 3.63%, Mo 0.8%, Ti 0.17%, Cu 0.35%, V 0.014%, S0.066%, P 0.0032%, Al 0.038%, and the balance is Fe and unavoidable impurities.

[0045] Preparation of welding wire: The welding wire raw materials are sequentially put into a vacuum induction furnace for smelting, pouring steel ingots, blanking and rolling on a rolling mill to obtain a wire rod with a diameter of Ф5.5mm; the wire rod is directly drawn into a three-roller die after mechanical shelling, straightening and belt grinding, and undergoes 12 continuous drawing passes, with the first 10 passes being the roller die and the last 2 passes being the eye die. The diameter of the finished product is Ф1.18mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0046] The welding method of the deposited metal in this embodiment is carried out in accordance with the provisions of GB / T 8110-2008. The deposited metal test uses a Q345 steel plate with a low alloy content as a deposited test plate. The test plate thickness is 20 mm, and a single-sided 22.5° groove is machined. Figure 1 Test Example The welding wire welds the isolation layer on the groove surface and the backing plate surface, and the weld metal impact performance test is carried out in accordance with GB / T2650-2022, and the weld metal tensile performance test is carried out in accordance with GB / T 2652-2022.

[0047] This embodiment adopts argon-rich (90% Ar+10% CO2) shielding gas welding with a gas flow rate of 20 L / min. For detailed welding parameters, see Table 1.

[0048] Comparative Example 1:

[0049] Welding wire diameter: 1.2mm. The chemical composition of the welding wire material is C 0.11%, Si 0.72%, Mn1.68%, Cr 0.38%, Ni 2.38%, Mo 0.65%, Ti 0.09%, Cu 0.08%, S 0.003%, P0.008%, Al 0.005%, and the balance is Fe and unavoidable impurities.

[0050] Preparation of welding wire: The welding wire raw materials are sequentially put into a vacuum induction furnace for smelting, pouring steel ingots, blanking and rolling on a rolling mill to obtain a wire rod with a diameter of Ф5.5mm; the wire rod is directly drawn into a three-roller die after mechanical shelling, straightening and belt grinding, and undergoes 12 continuous drawing passes, with the first 10 passes being the roller die and the last 2 passes being the eye die. The diameter of the finished product is Ф1.18mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0051] The welding method of the deposited metal in this comparative example is carried out in accordance with the provisions of GB / T 8110-2008. The deposited metal test uses Q345 steel plate with low alloy content as the deposited test plate. The test plate thickness is 20mm, and the single-sided single-sided 22.5° groove is machined. Figure 1 Test Example The welding wire welds the isolation layer on the groove surface and the backing plate surface, and the weld metal impact performance test is carried out in accordance with GB / T2650-2022, and the weld metal tensile performance test is carried out in accordance with GB / T 2652-2022.

[0052] This comparative example adopts argon-rich (80% Ar+20% CO2) shielding gas welding with a gas flow rate of 20 L / min. For detailed welding parameters, see Table 1.

[0053] Table 1 shows the welding parameters of Examples 1-3 and Comparative Example 1 under different welding heat input conditions

[0054]

[0055] The welds obtained in Examples 1 to 3 and Comparative Example 1 were subjected to mechanical property tests. The mechanical properties under different welding heat input conditions are shown in the attached figure. Figure 2 , Attachment Figure 3 As shown:

[0056] It can be seen from the mechanical properties of the deposited metal that the welding wires of Examples 1 to 3 are welded under the condition of a welding heat input of 10 to 40 kJ / cm, and the mechanical properties of the weld metal obtained are tensile strength greater than 1000 MPa and -40°C low-temperature impact absorption energy greater than 50 J. The tensile strength that meets the requirements of engineering applications is greater than 950 MPa, and the -40°C low-temperature impact absorption energy is greater than 47 J.

[0057] The welding wire of comparative example 1 is welded under the condition of welding heat input of 10-40 kJ / cm. When the heat input is greater than 20 kJ / cm, the mechanical properties of the weld metal are that the tensile strength of the weld metal is less than the tensile strength of 950 MPa required for engineering applications.

[0058] In summary, the welding wire of the present invention can meet the welding requirements of 1000MPa-level strength for low-alloy high-strength steel plates of different thicknesses.

[0059] The above are only preferred specific embodiments of the present invention, which are all different implementations based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A 1000MPa grade high strength and high toughness solid copper-free welding wire, characterized in that: The chemical composition includes by weight percentage: C 0.08-0.14%, Mn 1.60-2.00%, Si 0.50-0.80%, S 0.030-0.080%, P≤0.008%, Ni 2.50-4.0%, Cr 0.40-1.0%, Mo 0.40-1.0%, Ti 0.05-0.20%, V 0.005-0.02%, Cu0.10-0.50%, Al 0.015-0.05%, and the balance is Fe and unavoidable impurities.

2. The welding wire according to claim 1, characterized in that The unavoidable impurities are Sn<0.004%, As<0.001%, and Pb<0.001%.

3. The method for preparing the 1000MPa high-strength and high-toughness solid copper-free welding wire according to claim 1 or 2, characterized in that: The method: S1: placing the welding wire raw materials into a vacuum induction furnace in sequence for smelting, pouring steel ingots, blanking and rolling in a rolling mill to obtain wire rods; S2: After mechanical shelling, straightening and belt grinding, the wire rod is directly drawn into a three-roller die, and a total of 12 continuous drawing steps are performed to obtain the finished product; S3: The finished product is cleaned online, the surface is coated with an anti-rust coating, and the densely packed layers are wound on a coil to obtain the welding wire.

4. The preparation method according to claim 3, characterized in that: The diameter of the wire rod in S1 is Ф5.5mm.

5. The preparation method according to claim 3, characterized in that: The first 10 of the 12 continuous drawing passes in S2 are roller dies, and the last 2 are eye dies. The diameter of the finished product in S2 is Ф1.18mm.

6. Use of the 1000MPa high-strength and high-toughness solid copper-free welding wire according to claim 1 or 2 in high heat input argon-rich mixed gas shielded welding.

7. A method for high heat input argon-rich mixed gas shielded welding, characterized in that: The welding wire used in the welding method is as described in claim 1 or 2, and the volume fraction of the argon-rich mixed gas in the welding method is 80-95% Ar+5-20% CO2.

8. The welding method according to claim 7, characterized in that: The flow rate of argon-rich mixed gas is 20L / min.

9. The welding method according to claim 7, characterized in that: The welding parameters of the welding method are: welding current 230-300A, welding voltage 25-31V, welding speed 120-420cm / min, and interpass temperature 135-175°C.

10. Application of the welding method according to any one of claims 7 to 9 in welding low alloy high strength steel plates with a weld tensile strength of 1000-1100 MPa.

Images