A 960MPa high-strength gas-shielded solid welding wire and its preparation method

Abstract

The invention belongs to the field of solid welding wires and provides a 960MPa-grade high-strength gas-shielded solid welding wire and a preparation method thereof. The solid welding wire comprises the following components in weight percentage: C 0.03-0.11wt%; Mn 1.60-1.90wt%; Si 0.40-0.80wt%; P≤0.010wt%; S≤0.010wt%; Cr 0.20-0.50wt%; Ni 2.00-2.50wt%; Mo 0.40-1.00wt%; Ti 0.050-0.120wt%; Al 0.04-0.08wt%; O 0.0060-0.010wt%; the total amount of unavoidable impurity elements is ≤0.3wt%; and the balance is Fe. The 960MPa-grade high-strength gas-shielded solid welding wire described in the present invention has a deposited metal with good toughness, which can meet the welding requirements of high-strength steels with strength levels of 960MPa and above. At the same time, a smelting method for controlling oxygen content and an improved method for preparing the welding wire are provided, which can improve the quality of the welding wire products.

Description

Technical Field

[0001] The present invention belongs to the field of solid welding wires, and in particular relates to a 960MPa-grade high-strength gas-shielded solid welding wire and a preparation method thereof. Background Art

[0002] As domestic and international engineering machinery, coal machinery, marine engineering equipment, and hydropower equipment develop toward high quality, high strength, high toughness, large-scale, and lightweight construction, welding metal materials are expanding from traditional carbon steel and low-alloy steel to high-strength steel. Welding is an indispensable manufacturing process for the promotion and application of high-strength steel. The promotion and application of high-strength steel in the machinery manufacturing field has also promoted the rapid development of the high-strength gas-shielded solid welding wire industry. Therefore, developing matching welding materials and production processes for high-strength steel is the key to achieving high-quality welded joints. However, solid welding wire for high-strength steel faces a series of technical challenges in its manufacturing and application, including wire rod smelting, production drawing processes, and microstructure control.

[0003] During the production process, solid welding wire needs to go through the wire drawing process. The higher the strength, the lower the toughness of the wire rod raw material, the plasticity cannot be effectively guaranteed, and the drawability is reduced. This puts higher requirements on the production drawing process of solid welding wire, and there are various difficulties in high-strength gas-shielded solid welding wire. Summary of the Invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a 960MPa grade high-strength gas-shielded solid welding wire and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] The present invention provides a 960MPa grade high-strength gas shielded solid welding wire, which comprises the following components in percentage by weight:

[0007] C 0.03-0.11wt%; Mn 1.60-1.90wt%; Si 0.40-0.80wt%; P≤0.010wt%; S≤0.010wt%; Cr 0.20-0.50wt%; Ni 2.00-2.50wt%; Mo 0.40-1.00wt%; Ti 0.050-0.120wt%; Al0.04-0.08wt%; O 0.0060-0.010wt%; the total amount of unavoidable impurity elements ≤0.3wt%; the balance is Fe.

[0008] Furthermore, the mass ratio of Cr to Mo is 0.45-0.55:1.

[0009] Furthermore, the mass ratio of O to Ni is ≤0.004.

[0010] Furthermore, the mass ratio of O to Al is ≤0.16wt%.

[0011] The present invention also provides a method for preparing a 960MPa grade high-strength gas-shielded solid welding wire, which is characterized by comprising the following steps:

[0012] Step 1 is to smelt the pig iron to obtain wire rod;

[0013] Step 2 is to sequentially perform pre-drawing, primary spheroidizing annealing, rough drawing, secondary spheroidizing annealing, fine drawing, and copper plating on the wire rod to obtain the solid welding wire.

[0014] Furthermore, the smelting in step 1 includes the following steps:

[0015] The pig iron is subjected to converter steelmaking and then enters an LF furnace for refining, an intermediate alloy is added to the LF furnace, and the wire rod is obtained after the refining is completed.

[0016] Furthermore, the oxygen content of the material discharged from the converter steelmaking step is 300-800 ppm; and the temperature of the refining step is 1530-1580°C.

[0017] Furthermore, the master alloy has an oxygen content of 60-120 ppm and comprises the following components by weight: C ≤ 0.05 wt%, S ≤ 0.006 wt%, P ≤ 0.005 wt%, O 0.006-0.012 wt%, with the balance being Fe. The master alloy accounts for 0.1-0.5 wt% of the pig iron. The addition of the master alloy ensures that the welding wire composition meets the required oxygen content.

[0018] Furthermore, the temperature of the first spheroidizing annealing treatment is 750-770° C., and the time is 10-11 hours; the temperature of the second spheroidizing annealing treatment is 750-770° C., and the time is 10-11 hours.

[0019] Pre-drawing before annealing can reduce the compression ratio of the wire rod after spheroidizing annealing, making drawing easier. Pre-drawing also removes surface scale, improving surface cleanliness after spheroidizing annealing. Carbide fragmentation after pre-drawing serves as the nucleation core for annealing, while plastic deformation of the steel accumulates energy, driving structural changes during the annealing process. Therefore, the drawing process facilitates nucleation in the subsequent annealing process. The present invention sets the spheroidizing annealing process at 760°C for 10 hours followed by slow cooling.

[0020] Furthermore, the yield strength of the solid welding wire is ≥890MPa, the tensile strength is ≥960MPa, the elongation A is ≥14%, and the impact toughness at -40℃ is ≥47J. In addition, the molten iron has good fluidity, the arc is stable, and the molding is beautiful.

[0021] The functions of the chemical components are as follows:

[0022] Carbon improves the strength and hardness of the weld metal through its solid solution strengthening effect. It also increases the hardenability of the weld metal, making it easier to obtain a high-strength microstructure, indirectly increasing strength and hardness, but at the same time reducing plasticity and toughness. The increase in carbon can also lead to poor welding performance. High-carbon content molten metals are prone to hot and cold cracking during welding, seriously affecting weld quality.

[0023] Manganese acts as a deoxidizer and desulfurizer in weld metal, preventing the reaction of the weld metal with oxygen and sulfur, reducing the tendency for sulfur-induced hot cracking, and thus improving weldability. Manganese also helps refine the grain structure of the weld joint and promotes the formation of acicular ferrite, which can improve the overall mechanical properties of the weld metal, including strength and toughness. However, an increase in manganese content affects the carbon equivalent, which in turn leads to poor weldability. Furthermore, the manganese fume generated during welding is detrimental to welder health.

[0024] Silicon acts as a deoxidizer in welds, reducing the binding of iron and oxygen during welding and increasing the fluidity of molten iron, which helps improve weld metal quality. However, excessive molten iron fluidity can cause spattering, affecting weld quality and efficiency. Silicon dissolves in the weld structure, acting as a solid solution strengthening agent and thus increasing weld strength, but it also reduces the weld's plasticity and toughness.

[0025] P and S are detrimental elements in the deposited metal, significantly reducing the toughness and ductility of welded joints. This is because P can cause cold brittleness in the weld and increase crack sensitivity during welding. S is virtually insoluble in steel, but forms compounds with iron, primarily in the form of FeS. This compound, particularly when the liquid metal solidifies, tends to form a low-melting-point eutectic that accumulates at grain boundaries, increasing the tendency to hot cracking and reducing impact toughness.

[0026] The Ni element can refine the grain size of the weld metal, leading to an increase in acicular ferrite in the structure, lowering the ductile-brittle transition temperature, improving its impact toughness, and at the same time enhancing the hardenability of the weld metal, thereby improving the strength of the weld metal to a certain extent. When the Ni content increases to a certain amount, the hardenability of the weld metal is improved. As the tensile strength increases, the acicular ferrite decreases, and bainite or even martensite appears, reducing the impact toughness of the weld metal. Compared with other elements, the cost of Ni is relatively high.

[0027] Cr and Mo are the primary elements that enhance weld metal strength. Both Cr and Mo can significantly improve the hardenability of weld metal. As their content increases, the weld microstructure changes: proeutectoid ferrite and acicular ferrite decrease, the proportion of bainite increases, and even martensite appears. This increases the strength of the weld joint while reducing impact toughness. Therefore, the element content must be maintained within a certain range. Mo also ensures sufficient strength and toughness matching in the welding wire by refining the weld grain. Cr readily forms stable carbides with carbon in the alloy, and excessive levels can increase hot crack susceptibility during welding. Therefore, Mo is the primary strength-enhancing element in the alloy. However, due to its high cost, it can be replaced by a partial amount of Cr to enhance its strength, but the Cr content must be strictly controlled.

[0028] To ensure the comprehensive mechanical properties of the weld metal, the present invention incorporates Ti, a strong carbide-forming element, through microalloying. Ti forms TiN particles, which effectively prevent austenite grain growth during the welding thermal cycle, refining the grains and improving the toughness of the weld joint. However, excessive Ti in molten iron can affect its fluidity, causing it to become viscous.

[0029] Al is a strong deoxidizer that effectively reduces the oxygen content in weld metal. Al also combines with nitrogen to form AlN, which helps reduce nitrogen pores and the tendency of welds to experience delayed cracking. AlN is a small, insoluble particle that, when distributed in the molten pool, hinders grain growth during crystallization, refining the weld metal structure and improving its overall mechanical properties. However, excessive Al content can reduce the weld metal's resistance to hot cracking.

[0030] The O element can improve the fluidity of the molten iron in the molten pool by reducing the surface tension in the molten pool during the welding process. In order to control the quality of the weld, the product of the present invention has high requirements for the S and P contents, resulting in poor fluidity of the molten iron in the weld. Therefore, it is necessary to add some O elements to enhance the fluidity of the molten iron. However, as the oxygen content in the weld increases, the strength, hardness, plasticity and toughness all decrease, which leads to an increase in the Ni content. In addition, the melting point of Al oxide Al2O3 is very high. If it is present in the weld in a solid state, it is very easy to cause slag inclusion in the weld. This affects the plasticity and toughness of the weld. Therefore, the O content of the Al element should be controlled after it is increased to a certain amount.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] The 960MPa-grade high-strength gas-shielded solid welding wire described in the present invention has a deposited metal with good toughness, which can meet the welding requirements of high-strength steels with strength levels of 960MPa and above. At the same time, a smelting method for controlling oxygen content and an improved method for preparing the welding wire are provided, which can improve the quality of the welding wire products. DETAILED DESCRIPTION

[0033] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods.

[0034] The present invention will be described in detail below with reference to the embodiments.

[0035] Example 1

[0036] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0037] C is 0.085wt%, Mn is 1.75wt%, Si is 0.45wt%, Cr is 0.25wt%, Ni is 2.15wt%, Mo is 0.50wt%, Ti is 0.055wt%, Al is 0.045wt%, P is 0.015wt%, S is 0.020wt%, O is 0.0070wt%, and the balance is Fe and inevitable impurities.

[0038] A method for preparing a 960MPa grade high-strength gas shielded solid welding wire comprises the following steps:

[0039] Step 1 is to subject the pig iron to converter steelmaking, with the oxygen content of the furnace being 450ppm, and then enter the LF furnace for refining at a temperature of 1550°C, add a master alloy in the LF furnace (the oxygen content of the master alloy is 80ppm; the master alloy includes the following components in weight percentage: C: 0.04wt%, S: 0.005wt%, P: 0.004wt%, O: 0.011wt%, and the balance is Fe; the master alloy accounts for 0.3wt% of the mass of the pig iron), and obtain the wire rod after refining;

[0040] Step 2 is to pre-draw the wire rod, perform a spheroidizing annealing at 760°C for 10 hours, perform rough drawing, perform a secondary spheroidizing annealing at 760°C for 10 hours, perform fine drawing, and perform copper plating to obtain a 1.2 mm solid welding wire.

[0041] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0042] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0043] The yield strength of the weld metal after welding in this embodiment was tested to be 894 MPa, the tensile strength was 985 MPa, the elongation A=16.5%, and the average impact energy Akv=70-85 J at -40°C, indicating good welding processability.

[0044] Example 2

[0045] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0046] C is 0.095wt%, Mn is 1.80wt%, Si is 0.55wt%, Cr is 0.30wt%, Ni is 2.25wt%, Mo is 0.55wt%, Ti is 0.070wt%, Al is 0.055wt%, P is 0.022wt%, S is 0.018wt%, O is 0.0075wt%, and the balance is Fe and inevitable impurities.

[0047] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0048] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0049] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0050] The yield strength of the weld metal after welding in this embodiment was tested to be 908 MPa, the tensile strength was 1003 MPa, the elongation A=15.5%, and the average impact energy Akv=64-82 J at -40°C, indicating good welding processability.

[0051] Example 3

[0052] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0053] C is 0.10wt%, Mn is 1.85wt%, Si is 0.68wt%, Cr is 0.35wt%, Ni is 2.35wt%, Mo is 0.70wt%, Ti is 0.085wt%, Al is 0.065wt%, P is 0.020wt%, S is 0.015wt%, O is 0.0090wt%, and the balance is Fe and inevitable impurities.

[0054] The preparation method of a 960 MPa grade high strength gas shielded solid welding wire is the same as that in Example 1, and a finished solid welding wire of 1.0 mm is prepared.

[0055] In this embodiment, the welding current is 240-270A, the arc voltage is 26-28V, the welding speed is 24-33cm / min, and the welding line energy is 11.3-16.8KJ / cm.

[0056] The yield strength of the weld metal after welding in this embodiment was tested to be 899 MPa, the tensile strength was 1020 MPa, the elongation A=14.5%, and the average impact energy Akv=55-73 J at -40°C, indicating good welding processability.

[0057] Example 4

[0058] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0059] C is 0.105wt%, Mn is 1.85wt%, Si is 0.75wt%, Cr is 0.45wt%, Ni is 2.45wt%, Mo is 0.85wt%, Ti is 0.105wt%, Al is 0.065wt%, P is 0.015wt%, S is 0.015wt%, O is 0.0083wt%, and the balance is Fe and inevitable impurities.

[0060] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0061] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0062] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0063] The yield strength of the weld metal after welding in this embodiment was tested to be 893 MPa, the tensile strength was 1025 MPa, the elongation A=15.0%, and the average impact energy Akv=60-85 J at -40°C, indicating good welding processability.

[0064] Example 5

[0065] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0066] C is 0.098wt%, Mn is 1.70wt%, Si is 0.65wt%, Cr is 0.38wt%, Ni is 2.37wt%, Mo is 0.74wt%, Ti is 0.090wt%, Al is 0.062wt%, P is 0.013wt%, S is 0.022wt%, O is 0.0085wt%, and the balance is Fe and inevitable impurities.

[0067] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0068] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0069] In this embodiment, the welding current is 240-270A, the arc voltage is 26-28V, the welding speed is 24-33cm / min, and the welding line energy is 11.3-16.8KJ / cm.

[0070] The yield strength of the weld metal after welding in this embodiment was tested to be 911 MPa, the tensile strength was 1010 MPa, the elongation A=15.2%, and the average impact energy Akv=68-87 J at -40°C, indicating good welding processability.

[0071] Comparative Example 1

[0072] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0073] C is 0.085wt%, Mn is 1.75wt%, Si is 0.45wt%, Cr is 0.45wt%, Ni is 2.15wt%, Mo is 0.50wt%, Ti is 0.055wt%, Al is 0.045wt%, P is 0.015wt%, S is 0.020wt%, O is 0.0070wt%, and the balance is Fe and inevitable impurities.

[0074] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0075] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0076] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0077] The yield strength of the weld metal after welding in this embodiment was tested to be 891 MPa, the tensile strength was 987 MPa, the elongation A was 16.5%, and the average impact energy Akv was 35-60 J at -40°C. However, the welding processability was good.

[0078] Comparative Example 2

[0079] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0080] C is 0.085wt%, Mn is 1.75wt%, Si is 0.45wt%, Cr is 0.25wt%, Ni is 2.15wt%, Mo is 0.50wt%, Ti is 0.055wt%, Al is 0.045wt%, P is 0.015wt%, S is 0.020wt%, O is 0.0090wt%, and the balance is Fe and inevitable impurities.

[0081] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0082] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0083] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0084] The yield strength of the weld metal after welding in this embodiment was tested to be 900 MPa, the tensile strength was 1001 MPa, the elongation A=16.5%, and the average impact energy Akv=40-70 J at -40°C, but the welding processability was good.

[0085] Comparative Example 3

[0086] A 960MPa grade high-strength gas shielded solid welding wire, comprising the following components in percentage by weight:

[0087] C is 0.085wt%, Mn is 1.75wt%, Si is 0.45wt%, Cr is 0.25wt%, Ni is 2.15wt%, Mo is 0.50wt%, Ti is 0.055wt%, Al is 0.045wt%, P is 0.015wt%, S is 0.020wt%, O is 0.0085wt%, and the balance is Fe and unavoidable impurities.

[0088] The preparation method of a 960MPa grade high-strength gas shielded solid welding wire is the same as that in Example 1.

[0089] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0090] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0091] The yield strength of the weld metal after welding in this embodiment was tested to be 887 MPa, the tensile strength was 976 MPa, the elongation A was 16.5%, and the average impact energy Akv was 25-56 J at -40°C, indicating good welding processability.

[0092] Comparative Example 4

[0093] A 960MPa grade high-strength gas shielded solid welding wire, the proportion of which is the same as that of Example 1.

[0094] A method for preparing a 960MPa grade high-strength gas shielded solid welding wire comprises the following steps:

[0095] Step 1 is to subject the pig iron to converter steelmaking, with the oxygen content of the steel being 950ppm, and then to an LF furnace for refining at 1550°C. A master alloy is added to the LF furnace (the oxygen content of the master alloy is 60-120ppm; the master alloy comprises the following components in weight percentage: C: 0.04wt%, S: 0.005wt%, P: 0.004wt%, O: 0.011wt%, and the balance is Fe; the master alloy accounts for 0.4wt% of the pig iron). After refining, the wire rod is obtained, but the oxygen content of the wire rod exceeds the standard, reaching 0.015%;

[0096] Step 2 is to pre-draw the wire rod, perform a spheroidizing annealing at 760°C for 10 hours, perform rough drawing, perform a secondary spheroidizing annealing at 760°C for 10 hours, perform fine drawing, and perform copper plating to obtain a 1.2 mm solid welding wire.

[0097] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0098] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0099] The yield strength of the weld metal after welding in this embodiment was tested to be 905 MPa, the tensile strength was 1031 MPa, the elongation A=16.5%, and the average impact energy Akv=25-55 J at -40°C, indicating good welding processability.

[0100] Comparative Example 5

[0101] A 960MPa grade high-strength gas shielded solid welding wire, the proportion of which is the same as that of Example 1.

[0102] A method for preparing a 960MPa grade high-strength gas shielded solid welding wire comprises the following steps:

[0103] Step 1 is to subject the pig iron to converter steelmaking, with the oxygen content of the steel being 530ppm, and then to LF furnace refining at a temperature of 1565°C, to obtain the wire rod after refining;

[0104] Step 2 is to pre-draw the wire rod, perform a spheroidizing annealing at 760°C for 10 hours, perform rough drawing, perform a secondary spheroidizing annealing at 760°C for 10 hours, perform fine drawing, and perform copper plating to obtain a 1.2 mm solid welding wire.

[0105] The weld test plate was 20 mm thick using MIG / MAG welding. The base metal was then rimmed with the product to a thickness of 2 mm. The weld test plate had a V-shaped groove with a single-sided groove angle of 10°. The shielding gas used was a mixture of 80 vol% Ar and 20 vol% CO2 at a flow rate of 15-20 L / min.

[0106] In this embodiment, the welding current is 280-300 A, the arc voltage is 28-30 V, the welding speed is 30-42 cm / min, and the welding line energy is 11.2-12.9 KJ / cm.

[0107] The yield strength of the weld metal after welding in this embodiment was tested to be 910 MPa, the tensile strength was 1038 MPa, the elongation A=16.5%, and the average impact energy Akv=70-85 J at -40°C. The welding processability was poor, the molten iron fluidity was poor, and the weld formation was poor.

[0108] Comparative Example 6

[0109] A 960MPa grade high-strength gas shielded solid welding wire, the proportion of which is the same as that of Example 1.

[0110] A method for preparing a 960MPa grade high-strength gas shielded solid welding wire comprises the following steps:

[0111] Step 1 is to subject the pig iron to converter steelmaking, with the oxygen content of the steel being 590 ppm, and then to an LF furnace for refining at a temperature of 1570° C., adding a master alloy (the oxygen content of the master alloy is 80 ppm; the master alloy comprises the following components in weight percentages: C: 0.04wt%, S: 0.005wt%, P: 0.004wt%, O: 0.011wt%, and the balance is Fe; the master alloy accounts for 0.35wt% of the mass of the pig iron), and obtaining the wire rod after refining;

[0112] Step 2 involves subjecting the wire rod to a series of production processes, including pre-drawing, spheroidizing annealing at 760°C for 10 hours, rough drawing, fine drawing, and copper plating. While the rough drawing process proceeded smoothly after spheroidizing annealing, the wire rod was subjected to plastic deformation and work hardening due to the tensile force after rough drawing. This resulted in frequent wire breakage during fine drawing due to insufficient plasticity, making it impossible to produce finished welding wire.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A 960MPa grade high strength gas shielded solid welding wire, characterized by: The solid welding wire comprises the following components in weight percentage: C is 0.10wt%, Mn is 1.85wt%, Si is 0.68wt%, Cr is 0.35wt%, Ni is 2.35wt%, Mo is 0.70wt%, Ti is 0.085wt%, Al is 0.065wt%, P is 0.020wt%, S is 0.015wt%, O is 0.0090wt%, and the balance is Fe and unavoidable impurities; The mass ratio of O to Ni is ≤0.004; the mass ratio of O to Al is ≤0.16; The method for preparing the 960MPa grade high-strength gas shielded solid welding wire comprises the following steps: Step 1 is to smelt the pig iron to obtain wire rod; Step 2 is to sequentially perform pre-drawing, primary spheroidizing annealing, rough drawing, secondary spheroidizing annealing, fine drawing, and copper plating on the wire rod to obtain the solid welding wire; The smelting in step 1 comprises the following steps: subjecting the pig iron to converter steelmaking, and then to LF furnace refining, adding intermediate alloy in the LF furnace, and obtaining the wire rod after refining; The oxygen content of the master alloy is 60-120 ppm; the master alloy comprises the following components in weight percentage: C≤0.05wt%, S≤0.006wt%, P≤0.005wt%, O: 0.006-0.012wt%, and the balance is Fe; the master alloy accounts for 0.1-0.5wt% of the pig iron; The oxygen content of the material discharged from the converter steelmaking step is 300-800 ppm; the temperature of the refining step is 1530-1580°C.

2. The 960MPa grade high strength gas shielded solid welding wire according to claim 1, characterized in that: The mass ratio of Cr to Mo is 0.45-0.55:

1.

3. The method for preparing the 960 MPa grade high strength gas shielded solid welding wire according to claim 1, characterized in that: The temperature of the first spheroidizing annealing treatment is 750-770° C., and the time is 10-11 hours; the temperature of the second spheroidizing annealing treatment is 750-770° C., and the time is 10-11 hours.

4. The method for preparing the 960 MPa grade high strength gas shielded solid welding wire according to claim 1, characterized in that: The yield strength of the solid welding wire is ≥890MPa, the tensile strength is ≥960MPa, the elongation A is ≥14%, and the impact toughness at -40°C is ≥47J.