1100 mpa grade metal cored gas shielded welding wire and method of use

Abstract

The application discloses a 1100MPa-grade metal powder core gas shielded welding wire and a use method thereof, and belongs to the technical field of welding, which comprises 61-73wt% of steel strips and 27-39wt% of alloy powders, the steel strips are rolled into circular tubes, laser welding is adopted for jointing, the welded seamless steel tubes are polished to be prepared, the alloy powders are added into the seamless steel tubes, wire drawing is performed, the wire is collected, surface treatment is performed, layer winding is performed, and finally the 1100MPa-grade metal powder core gas shielded welding wire is prepared; the use method is that mixed gas is used for gas protection; during welding, the first layer welding current is 112-126A, the voltage is 17.6-18.8V, and the welding speed is 18-20cm / min; the second layer welding current is 251-276A, the voltage is 27.8-29.9V, and the welding speed is 44-48cm / min; the subsequent welding is the same as the second layer welding; at present, Q1100 and above high-strength engineering machinery steels have been widely applied in the manufacturing of crane booms, hydraulic supports and other structures, and the structure weight is greatly reduced. The application can weld the Q1100E engineering machinery steel, the welding forming is good, and the use requirement is met.

Description

Technical Field

[0001] This invention belongs to the field of welding technology and relates to a metal-cored gas shielded welding wire and its application method; specifically, it relates to an 1100MPa grade metal-cored gas shielded welding wire and its application method. Background Technology

[0002] Currently, Q1100E quenched and tempered steel plates for mechanical engineering have been developed and put into use both domestically and internationally. However, due to the lack of welding materials with matching strength and toughness, most manufacturers have to use 90kg-grade or even lower strength welding materials for welding, resulting in insufficient joint strength. Therefore, the design must avoid joint load-bearing, leading to low utilization of the steel plate's performance. Some companies have also abandoned welding and instead use riveting and other methods to use steel plates, which greatly wastes the steel plate's performance.

[0003] With the increasing maturity of robotic welding, gas-shielded welding wire is the primary welding material for construction machinery. Welding electrodes and submerged arc welding are rarely used due to their inconvenience and difficulty in automation. Currently, the highest tensile strength of gas-shielded welding wire, both domestically and internationally, is around 1000 MPa, and there are no mature products with strengths above 1100 MPa. The main reason is that it is difficult to balance strength and toughness at high strength levels to meet the requirements for low-temperature impact. This restricts the application of Q1100E steel plates.

[0004] Therefore, there is a need to develop a new welding material for welding Q1100E steel plates to achieve equal strength matching, fully utilize the performance of the steel plates, and reduce structural weight. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a 1100MPa grade metal-cored gas shielded welding wire and its application method, which can weld Q1100E engineering machinery steel with good weld formation and meet the application requirements.

[0006] Technical solution: The present invention provides a 1100MPa grade metal-cored gas shielded welding wire, wherein the 1100MPa grade metal-cored gas shielded welding wire is composed of 61-73wt% steel strip and 27-39wt% alloy powder.

[0007] Furthermore, the chemical composition of the steel strip, by weight percentage, is as follows: C 0.008–0.019 wt%, Si 0.51–0.70 wt%, Mn 0.29–0.57 wt%, Cr 0.15–0.23 wt%, Ni 0.05–0.13 wt%, Cu ≤ 0.15 wt%, Ti 0.05–0.12 wt%, P ≤ 0.002 wt%, S ≤ 0.01 wt%, with the balance being Fe and unavoidable impurities.

[0008] Furthermore, the chemical composition of the alloy powder, by weight percentage, is as follows: electrolytic manganese 1.45–2.08 wt%, nickel powder 2.98–3.41 wt%, low-carbon ferrochrome powder 0.89–1.24 wt%, molybdenum powder 0.84–1.31 wt%, with the balance being iron powder.

[0009] Furthermore, the chemical composition of the low-carbon ferrochrome powder, by weight percentage, is as follows: Cr 94-96 wt%, C 4-6 wt%, with the balance being iron and unavoidable impurities;

[0010] The particle size of high-carbon ferrochrome is ≤0.30mm.

[0011] Furthermore, a method for preparing an 1100MPa grade metal powder-cored gas shielded welding wire includes the following steps: rolling a steel strip into a circular tube with a diameter of 2.4mm, laser welding to align the seams, grinding the welded part to form a seamless steel tube, adding alloy powder into the seamless steel tube, drawing and reducing the diameter, winding the wire, surface treating, and layering to obtain a metal powder-cored gas shielded welding wire with a diameter of 1.2mm.

[0012] Furthermore, a method for using an 1100MPa grade metal-cored gas shielded welding wire: It is mainly used for butt welding and fillet welding at position 1G of Q1100E steel plates, employing a gas shielding mixture of 75% Ar + 23% CO2 + 2% He, with a gas flow rate of 18–20 L / min. Preheating is not required before welding, and the layer temperature is maintained at 30–50℃ during welding.

[0013] During welding, the welding current for the first layer is 112–126A, the voltage is 17.6–18.8V, and the welding speed is 18–20cm / min; the welding current for the second layer is 251–276A, the voltage is 27.8–29.9V, and the welding speed is 44–48cm / min; subsequent welding uses the same parameters as the second layer.

[0014] Beneficial Effects: Compared with the prior art, the features of this invention are: 1. This invention uses a seamless steel tube made of steel strip to prepare metal-cored welding wire; the seamless steel tube form avoids the disadvantages of traditional open U-shaped tubes being prone to water absorption and moisture absorption; 2. The steel strip used in this invention adds Ti and Cu alloying elements to the conventional Q235B steel strip; Ti and Cu elements can refine the grains of the weld and improve strength and toughness, but Ti and Cu metal powders are easily oxidized, so they are added to the steel strip rather than mixed in the alloy powder; 3. The protective gas in this invention is a mixed protective gas of 75% Ar + 23% CO2 + 2% He, wherein the purity of Ar is 99.999%, the purity of CO2 is 99.995%, and the purity of He is 99.999%; CO2 undergoes reactions of 2CO2=2CO+O2 and CO2=C+O2 at high temperatures, thus exhibiting oxidizing properties and causing a large amount of metal alloying elements in the weld to burn off. Ar is an inert gas and does not react during welding. He can increase the weld penetration, meeting the requirement of leaving a blunt edge to avoid misalignment in engineering applications. 4. In this invention, during welding, the welding current for the first layer is 112-126A, the voltage is 17.6-18.8V, and the welding speed is 18-20cm / min; the welding current for the second layer is 251-276A, the voltage is 27.8-29.9V, and the welding speed is 44-48cm / min; subsequent welding parameters are the same as the second layer welding parameters; the parameters used for the first layer welding, i.e., the root pass welding, have a lower heat input, mainly to prevent the high fusion ratio between the root weld and the base metal, which would lead to a decrease in performance; the parameters for the second layer and subsequent welding, i.e., the fill and cover welds, have relatively higher current and voltage to increase efficiency, but the welding speed is very high to prevent the formation of coarse martensite due to high heat input, thereby reducing low-temperature toughness; the above welding parameters are the optimal process range to ensure welding performance. Detailed Implementation

[0015] The present invention will be further described below with reference to embodiments.

[0016] Example 1

[0017] The above-mentioned welding wire and method were used to weld 8mm thick Q1100E steel.

[0018] Beveling: Create a 30°±2° V-shaped bevel on one side, leaving a 2mm blunt edge.

[0019] The chemical composition of the steel strip of the metal-cored gas shielded welding wire used for welding is as follows: C 0.008wt%, Si 0.68wt%, Mn 0.57wt%, Cr 0.23wt%, Ni 0.10wt%, Cu≤0.15wt%, Ti 0.12wt%, P≤0.002wt%, S≤0.01wt%, with the balance being Fe and unavoidable impurities.

[0020] The chemical composition of the alloy powder is as follows: 2.08 wt% electrolytic manganese, 3.15 wt% nickel powder, 1.24 wt% low-carbon ferrochrome powder, 1.31 wt% molybdenum powder, and the balance is iron powder.

[0021] The protective gas composition in this invention is a mixture of 75% Ar, 23% CO2, and 2% He. During welding, the flow rate of the protective gas is 20-25 L / min.

[0022] Assembly welding is performed using conventional spot welding methods, with no gaps left at the root.

[0023] The welding current for the first layer is 112–126A, the voltage is 17.6–18.8V, and the welding speed is 18–20cm / min; the welding current for the second and third layers is 251–276A, the voltage is 27.8–29.9V, and the welding speed is 44–48cm / min; after cleaning the back side with carbon arc gouging, the same parameters as for the second and third layers are used for welding; the interpass temperature is controlled below 50℃.

[0024] Welding was performed using the aforementioned metal-cored gas shielded welding wire and application method. The weld formation was good, and the flaw detection was satisfactory. The tensile strength of the joint was 1126 and 1133 MPa, and there were no cracks during lateral bending. The low-temperature impact resistance of the weld at -40℃ was 30, 28, and 32 J, meeting the application requirements.

[0025] Example 2

[0026] The above-mentioned welding wire and method were used to weld 12mm thick Q1100E steel.

[0027] Beveling: Create a 30°±2° V-shaped bevel on one side, leaving a 2mm blunt edge.

[0028] The chemical composition of the steel strip of the metal-cored gas shielded welding wire used for welding is as follows: C 0.019wt%, Si 0.51wt%, Mn 0.29wt%, Cr 0.15wt%, Ni 0.05wt%, Cu≤0.15wt%, Ti 0.05wt%, P≤0.002wt%, S≤0.01wt%, with the balance being Fe and unavoidable impurities.

[0029] The chemical composition of the alloy powder is as follows: 1.45 wt% electrolytic manganese, 2.98 wt% nickel powder, 0.89 wt% low-carbon ferrochrome powder, 0.84 wt% molybdenum powder, and the balance is iron powder.

[0030] The protective gas composition in this invention is a mixture of 75% Ar, 23% CO2, and 2% He. During welding, the flow rate of the protective gas is 20-25 L / min.

[0031] Assembly welding is performed using conventional spot welding methods, with no gaps left at the root.

[0032] The welding current for the first layer is 112–126A, the voltage is 17.6–18.8V, and the welding speed is 18–20cm / min; the welding current for the second, third, and fourth layers is 251–276A, the voltage is 27.8–29.9V, and the welding speed is 44–48cm / min; after cleaning the back side with carbon arc gouging, the same parameters as for the second, third, and fourth layers are used for welding; the interpass temperature is controlled below 50℃.

[0033] Welding was performed using the aforementioned metal-cored gas shielded welding wire and application method. The weld formation was good, and the flaw detection was satisfactory. The tensile strength of the joint was 1176 and 1183 MPa, and there were no cracks during lateral bending. The weld's low-temperature impact resistance at -40℃ was 27, 28, and 28 J, meeting the application requirements.

[0034] Example 3

[0035] The above-mentioned welding wire and method were used to weld 18mm thick Q1100E steel.

[0036] Beveling: Create a 30°±2° X-shaped bevel on one side, leaving a 1mm blunt edge.

[0037] The chemical composition of the steel strip of the metal-cored gas shielded welding wire used for welding is as follows: C 0.014wt%, Si 0.70wt%, Mn 0.41wt%, Cr 0.19wt%, Ni 0.13wt%, Cu≤0.15wt%, Ti 0.09wt%, P≤0.002wt%, S≤0.01wt%, with the balance being Fe and unavoidable impurities.

[0038] The chemical composition of the alloy powder is as follows: 1.76 wt% electrolytic manganese, 3.41 wt% nickel powder, 1.05 wt% low-carbon ferrochrome powder, 1.11 wt% molybdenum powder, and the balance is iron powder.

[0039] The protective gas composition in this invention is a mixture of 75% Ar, 23% CO2, and 2% He. During welding, the flow rate of the protective gas is 20-25 L / min.

[0040] Assembly welding is performed using conventional spot welding methods, with no gaps left at the root.

[0041] The welding current for the first layer is 112–126 A, the voltage is 17.6–18.8 V, and the welding speed is 18–20 cm / min. The welding current for the second layer and subsequent layers is 251–276 A, the voltage is 27.8–29.9 V, and the welding speed is 44–48 cm / min. The interpass temperature is controlled below 50℃.

[0042] Welding was performed using the aforementioned metal-cored gas shielded welding wire and application method. The weld formation was good and the flaw detection was qualified. The tensile strength of the joint was 1116 and 1143 MPa, and there were no cracks in the side bending. The low-temperature impact strength of the weld at -40℃ was 31, 34, and 28 J, which met the application requirements.

[0043] Currently, high-strength engineering machinery steel of Q1100 and above is widely used in the manufacture of crane booms, hydraulic supports, and other structures, significantly reducing structural weight. The 1100MPa grade metal-cored gas shielded welding wire and its application method of this invention can achieve welding of Q1100E steel plates, and have broad application prospects.

Claims

1. A 1100MPa grade metal-cored gas shielded welding wire, characterized in that, The 1100MPa grade metal-cored gas shielded welding wire comprises 61-73wt% steel strip and 27-39wt% alloy powder; The chemical composition of the steel strip, by weight percentage, is as follows: C: 0.008–0.019 wt%, Si: 0.51–0.70 wt%, Mn: 0.41–0.57 wt%, Cr: 0.15–0.23 wt%, Ni: 0.05–0.13 wt%, Cu ≤ 0.15 wt%, Ti: 0.05–0.12 wt%, P ≤ 0.002 wt%, S ≤ 0.01 wt%, with the balance being Fe and unavoidable impurities; The chemical components of the alloy powder, by weight percentage, are as follows: electrolytic manganese: 1.45–2.08 wt%, nickel powder: 2.98–3.41 wt%, low-carbon ferrochrome powder: 0.89–1.24 wt%, molybdenum powder: 0.84–1.31 wt%, with the balance being iron powder; The chemical composition of the low-carbon ferrochrome powder, by weight percentage, is as follows: Cr: 94-96 wt%, C: 4-6 wt%, with the balance being iron and unavoidable impurities; Its preparation steps are as follows: the prepared steel strip is rolled into a round tube, the seam is welded by laser, and after welding, it is ground into a seamless steel tube. Then, the prepared alloy powder is added into the seamless steel tube, the wire is drawn and reduced in diameter, the wire is wound, the surface is treated, and the wire is layered and wound to finally obtain 1100MPa grade metal powder core gas shielded welding wire. The diameter of the prepared circular tube is 2.4 mm; the diameter of the prepared 1100 MPa grade metal powder core gas shielded welding wire is 1.2 mm; it is used for 1G position butt welding and fillet welding of Q1100E steel plate; Its usage process is as follows: a gas protection gas mixture of 75%Ar + 23%CO2 + 2%He is used; no preheating is required before welding, and the layer temperature is ensured during the welding process; The gas flow rate in the gas protection system is 18~20L / min; the temperature of the gas layer is between 30~50℃. During welding, the welding current for the first layer is 112~126A, the voltage is 17.6~18.8V, and the welding speed is 18~20cm / min; the welding current for the second layer is 251~276A, the voltage is 27.8~29.9V, and the welding speed is 44~48cm / min; and the subsequent welding parameters are the same as those for the second layer.