Efficient stainless steel argon arc welding wire and preparation method thereof

Abstract

The invention relates to the technical field of argon arc welding stainless steel wires, in particular to an efficient stainless steel argon arc welding wire and a preparation method thereof. When a large-wall-thickness stainless steel weldment is welded, the welding speed of a conventional stainless steel argon arc welding wire is increased, and the welding defects of incomplete fusion, undercut and air holes are easily caused. In order to solve the technical problems, the efficient stainless steel argon arc welding wire is provided, the Mo element, the Ti element, the Nb element and the like are added into the components of the efficient stainless steel argon arc welding wire at the same time, the adding amount of all the elements is reasonably controlled, meanwhile, a special welding wire preparation technology is combined, and the obtained stainless steel argon arc welding wire is suitable for welding of large-size stainless steel parts with the thickness ranging from 50 mm to 100 mm; the highest welding speed can reach 30 cm / min, and welding defects such as undercut and air holes are not prone to occurring in the welding process.

Description

Technical Field

[0001] The invention relates to the technical field of argon arc welding stainless steel wires, and in particular to a high-efficiency stainless steel argon arc welding wire and a preparation method thereof. Background Art

[0002] In the field of industrial manufacturing, argon arc welding (TIG welding) is widely used in the connection of stainless steel weldments due to its excellent welding quality. However, for the welding needs of thick-walled and large-sized stainless steel weldments, traditional argon arc welding technology faces significant efficiency bottlenecks and technical defects, and it is difficult to meet the high standards of modern production. The specific shortcomings are reflected in the following aspects:

[0003] (1) Conflict between deposition efficiency and cycle cost

[0004] Conventional stainless steel argon arc welding wire has a low deposition rate, which leads to a longer welding time per unit length, especially when facing thick wall welds, multi-layer and multi-pass welding processes are required, which further shortens the welding cycle. Long production cycles not only reduce equipment utilization, but also lead to higher labor, energy and comprehensive operating costs.

[0005] (2) Frequent occurrence of speed-sensitive defects

[0006] When the welding speed is increased to improve efficiency, welding defects such as lack of fusion, undercut, and porosity are easily caused. The repair of such defects requires secondary heat treatment and machining, which not only increases the time cost, but also may cause the mechanical properties of the weldment to decrease due to the superposition of the heat-affected zone, posing a structural safety hazard.

[0007] (3) The process adaptability is limited

[0008] Existing welding wires have poor adaptability to the working conditions of weldments with different wall thicknesses, and welding parameters (such as current, voltage, gas flow, etc.) need to be adjusted frequently. The parameter adjustment process relies on manual experience and is difficult to achieve standardized control, resulting in fluctuations in welding quality, especially inefficiency in welding complex structural parts.

[0009] (4) Weld formation and subsequent processing burden

[0010] The weld forming coefficient of traditional welding wire is low, which is prone to problems such as uneven width and excessive excess height, affecting the appearance quality of the weldment. At the same time, in order to achieve the designed dimensional accuracy, subsequent processing steps such as grinding and polishing are required, which further prolongs the production cycle and increases material loss. Summary of the invention

[0011] The problem in the prior art is that when welding thick stainless steel weldments, increasing the welding speed of conventional stainless steel argon arc welding wires can easily cause welding defects such as lack of fusion, undercut, and pores. In view of the above technical problems, the present invention provides a high-efficiency stainless steel argon arc welding wire, which comprises the following components in terms of mass percentage:

[0012] Cr: 18-22%;

[0013] Ni: 8-12%;

[0014] Mo: 2-4%;

[0015] Mn: 1-3%;

[0016] Si: 0.5-1.5%;

[0017] C: 0.03-0.08%;

[0018] Nb: 0.3-0.8%;

[0019] N: 0.05-0.15%;

[0020] Ti: 0.1-0.3%;

[0021] The balance is Fe and inevitable impurities.

[0022] Preferably, the method for preparing a high-efficiency stainless steel argon arc welding wire comprises the following steps:

[0023] (1) Raw material preparation: weigh the corresponding raw material ingredients according to the formula;

[0024] (2) melting, placing the weighed raw materials in step (1) into a vacuum melting furnace for vacuum melting, and obtaining an alloy melt after the vacuum melting is completed;

[0025] (3) refining, adding a refining agent to the alloy melt to remove inclusions in the alloy melt to obtain a refined melt;

[0026] (4) casting, after the refining is completed, the refined solution obtained in step (3) is cast into a water-cooled mold through a guide device, so that the refined molten liquid is cooled at a high speed to form an ingot;

[0027] (5) Forging, in which the ingot is refined by hot working deformation to form a blank;

[0028] (6) Rolling: the billet is rolled in multiple passes at high temperature to form a welding wire of the required size;

[0029] (7) Surface treatment: the welding wire obtained in step (6) is pickled, washed with water, and dried in sequence to obtain a high-efficiency stainless steel argon arc welding wire.

[0030] Preferably, the vacuum degree during vacuum melting is 5×10 -3 Pa.

[0031] Preferably, the protective gas during the vacuum melting process is argon, and the gas pressure is 0.04-0.06 MPa.

[0032] Preferably, the temperature during vacuum melting is 1550-1650° C. and the time is 2-3 h.

[0033] Preferably, the refining agent is composed of calcium oxide and magnesium fluoride in a mass ratio of 3:2, and the added amount is 0.8-1.2% of the total weight of the alloy melt.

[0034] Preferably, the refining temperature is 1720-1780°C, and the refining time is 30-45 min.

[0035] Preferably, the pouring temperature is 1480-1520°C.

[0036] Preferably, the water-cooled mold is a water-cooled copper mold, and the flow rate of the cooling water is 0.5-1.5 m / s.

[0037] Preferably, the forging temperature is 1100-1200°C, the forging ratio is 4-6, the forging speed is 5-10 mm / s, and the single pressing amount is 10-20 mm.

[0038] Preferably, the reduction in each pass during the rolling process is 5-15%, and the rolling temperature is 950-1050°C.

[0039] Preferably, during the rolling process, when obvious work hardening is found in the billet, intermediate annealing treatment is required, with the annealing temperature being 800-900° C. and the holding time being 1-2 h.

[0040] Preferably, the acid solution used for pickling is a mixed solution of hydrochloric acid and nitric acid in a volume ratio of 3:1, the pickling temperature is 40-60° C., and the pickling time is 10-20 min.

[0041] The above-mentioned high-efficiency stainless steel argon arc welding wire is used as the welding material. The length of the large-size stainless steel part is 1000-3000mm, the width is 800-2000mm, and the thickness is 50-100mm. The welding speed is any point value in the range of 12-30cm / min, the welding current is 120-320A, the welding voltage is 18-28V, the cladding speed is 3.0kg / h, and the shielding gas flow rate is set to 12-18L / min.

[0042] The present invention has the following beneficial effects:

[0043] The stainless steel argon arc welding wire obtained by the present invention effectively overcomes many problems existing in the existing conventional stainless steel argon arc welding wire in high-speed welding of large-size stainless steel parts, and provides an ideal welding material and process solution for large-wall thickness, large-size weldments and various stainless steel welding operations. It has significant technical advantages and broad application prospects, and can effectively promote efficient and high-quality development in the field of stainless steel welding. DETAILED DESCRIPTION

[0044] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0045] The purity of the metal raw materials in the following embodiments of the present invention is not less than 99.5%.

[0046] The Cr element is provided by ferrochromium alloy, the Ni element is provided by nickel plate or nickel particles, the Mo element is provided by ferromolybdenum alloy, the Mn element is provided by ferromanganese alloy, the Si element is provided by ferrosilicon alloy, the C element is provided by analytical pure graphite powder, the Nb element is provided by ferroniobium alloy, the N element is provided by chromium nitride, the Ti element is provided by ferrotitanium alloy, the Fe element is provided by industrial pure iron, the Al element is provided by ferroaluminum alloy, the Co element is provided by ferrocobalt alloy, and the V element is provided by ferrovanadium alloy.

[0047] In the present invention, the test standard for impact toughness is GB / T229-2020 "Metallic Materials Charpy Pendulum Impact Test Method". The test standard for room temperature tensile strength is GB / T228.1-2021 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method". The test standard for room temperature elongation is GB / T228.1-2021 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method".

[0048] Example 1

[0049] A high-efficiency stainless steel argon arc welding wire, the composition of which is as follows in terms of mass percentage:

[0050] Cr: 20.5%;

[0051] Ni: 10.5%;

[0052] Mo: 3.5%;

[0053] Mn: 2.2%;

[0054] Si: 1.0%;

[0055] C: 0.045%;

[0056] Nb: 0.7%;

[0057] N: 0.12%;

[0058] Ti: 0.25%;

[0059] The balance is Fe and inevitable impurities.

[0060] (1) Raw material preparation: According to the formula, use a high-precision electronic scale with an accuracy of ±0.01g to accurately weigh the raw materials corresponding to each element.

[0061] (2) Alloy smelting: Place the formulated raw materials in a vacuum arc melting furnace. First, start the vacuum system and evacuate the furnace to a pressure below 5×10 -3 Pa, use the vacuum detection device to monitor the vacuum degree in the furnace in real time, ensure that it meets the predetermined requirements, and then slowly fill in argon as a protective gas, and accurately control the argon flow rate through the gas flow control valve to maintain the pressure in the furnace within a stable range of 0.05MPa. Then, use a heating device with precisely adjustable power to gradually increase the temperature to 1600℃, and the heating rate is controlled at 12℃ / min. After reaching the predetermined temperature, keep it warm for 2.5h. During this period, the melt is continuously and evenly stirred by a stirring device, and the stirring speed is set to 40r / min to ensure that the raw materials are fully melted and evenly mixed to form a uniform alloy melt, to ensure that each element is evenly distributed in the melt, and to avoid component segregation;

[0062] (3) Refining: Add a refining agent to the smelted alloy melt, wherein the refining agent is composed of calcium oxide and magnesium fluoride in a mass ratio of 3:2, and the amount of the refining agent added is 1% of the total weight of the alloy melt. The refining agent is added to the melt at a uniform speed through a high-precision metering and feeding device. After the addition, the stirring device is started to continuously stir, and the stirring speed is adjusted to 50 r / min. The temperature is kept for 40 minutes. The chemical reaction and adsorption of the refining agent with the inclusions and gases in the melt are used to remove the inclusions (such as oxides, sulfides, etc.) and gases (such as hydrogen, oxygen, etc.) in the melt, thereby improving the purity of the alloy, optimizing the internal quality of the weld metal, and reducing welding defects caused by inclusions and gases.

[0063] (4) Casting: After refining, the alloy melt is slowly cast into a water-cooled copper mold through a guide device at a temperature of 1500°C (the melt temperature is monitored in real time by a temperature sensor). The cooling water flow rate of the water-cooled copper mold is controlled at 1m / s. The melt is rapidly solidified through efficient cooling to form an ingot with a dense internal structure and no obvious defects.

[0064] (5) Forging: The ingot is heated to 1150°C and forged using a forging device with precise control function. The forging ratio is set to 5. During the forging process, the forging pressure and the deformation of the billet are monitored in real time by a pressure sensor and a displacement sensor. The forging speed is strictly controlled to be 8 mm / s and the single pressing amount is 15 mm to prevent defects such as cracks and folds in the billet, so that the ingot is gradually deformed into a billet with a diameter that meets the requirements of subsequent processing.

[0065] (6) Rolling: The forged billet is heated to 1000°C and rolled into welding wire of the required diameter through a multi-pass rolling process using a high-precision rolling mill. The roller surface of the rolling mill is specially treated to have good wear resistance and smoothness to ensure the surface quality of the welding wire. During rolling, the reduction in each pass should be uniform and reasonable, and the reduction should be controlled at 10%. After rolling three times, the billet is found to have obvious work hardening. The billet is placed in an annealing furnace and annealed at 850°C for 1.5 hours to eliminate the work hardening and restore the plasticity and toughness of the billet. The billet is then rolled until it is rolled into a welding wire with a diameter of 1.2 mm.

[0066] (7) Surface treatment: The surface of the rolled welding wire is pickled, washed, dried, etc. The pickling is carried out using a pickling solution prepared by mixing hydrochloric acid (mass concentration of 15%) and nitric acid (mass concentration of 10%) in a volume ratio of 3:1. The temperature of the pickling solution is controlled at 50°C. The welding wire is immersed in the pickling solution for pickling for 15 minutes. The pickling solution reacts chemically with impurities such as oxide scale on the surface of the welding wire to remove the oxide scale on the surface. After pickling, the welding wire is immediately placed in running clean water for washing for 8 minutes to ensure that the residual pickling solution is completely removed. Finally, the washed welding wire is placed in a drying device and dried at 90°C until the surface of the welding wire is completely dry to obtain a high-efficiency stainless steel argon arc welding wire.

[0067] The high-efficiency stainless steel argon arc welding wire obtained in Example 1 was used for manufacturing experiments. Taking the manufacture of a large-sized stainless steel structural part (2000 mm long, 1000 mm wide, 50 mm thick, and made of stainless steel 304) as an example, the set welding current of the argon arc welding equipment was 120 A, the welding voltage was 18 V, the cladding speed was 3.2 kg / h, the welding speed was 15 cm / min, and the shielding gas flow rate was 12 L / min, so as to meet the needs of high-efficiency welding of large-sized weldments. During the argon arc welding process, it can be clearly observed that the deposited metal exhibits good fluidity and can be quickly and evenly accumulated at the welding position. Even in the face of different welding requirements for various parts of large-sized weldments, it can still be accurately formed according to the preset shape, effectively avoiding the occurrence of common welding defects such as undercut, lack of fusion, and pores. The overall surface of the formed structural part is smooth and the weld appearance quality is good.

[0068] The performance test of the manufactured large-sized stainless steel structural parts showed that the room temperature tensile strength of the weld metal reached 700MPa, the yield strength reached 550MPa, and the elongation reached 30%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts were placed in a 3.5% sodium chloride aqueous solution for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate was less than 0.05mm / year, which shows that the structural parts have excellent corrosion resistance, which is sufficient to cope with the use requirements under complex working conditions such as marine environment and chemical environment, and verifies the significant advantages of the welding wire of the present invention in the large-sized high-efficiency argon arc welding manufacturing application, and can meet the dual needs of large-sized stainless steel weldments for high-efficiency welding and high-quality performance.

[0069] Example 2

[0070] A high-efficiency stainless steel argon arc welding wire, the composition of which is as follows in terms of mass percentage:

[0071] Cr: 21%;

[0072] Ni: 11%;

[0073] Mo: 3.8%;

[0074] Mn: 2.5%;

[0075] Si: 1.2%;

[0076] C: 0.05%;

[0077] Nb: 0.75%;

[0078] N: 0.13%;

[0079] Ti: 0.28%;

[0080] The balance is Fe and inevitable impurities.

[0081] (1) Raw material preparation: According to the formula, use a high-precision electronic scale with an accuracy of ±0.01g to accurately weigh the raw materials corresponding to each element.

[0082] (2) Alloy smelting: Place the formulated raw materials in a vacuum arc melting furnace. First, start the vacuum system and evacuate the furnace to a pressure below 4×10 -3 Pa, use the vacuum detection device to monitor the vacuum degree in the furnace in real time, ensure that it meets the predetermined requirements, and then slowly fill in argon as a protective gas, and accurately control the argon flow rate through the gas flow control valve to maintain the pressure in the furnace within a stable range of 0.045MPa. Then, use a heating device with precisely adjustable power to gradually increase the temperature to 1580℃, and the heating rate is controlled at 10℃ / min. After reaching the predetermined temperature, keep it warm for 2h. During this period, the melt is continuously and evenly stirred by a stirring device, and the stirring speed is set to 35r / min to ensure that the raw materials are fully melted and evenly mixed to form a uniform alloy melt, ensure that each element is evenly distributed in the melt, and avoid component segregation;

[0083] (3) Refining: Add a refining agent to the smelted alloy melt, wherein the refining agent is composed of calcium oxide and magnesium fluoride in a mass ratio of 3:2, and the amount of the refining agent added is 0.9% of the total weight of the alloy melt. The refining agent is added to the melt at a uniform speed through a high-precision metering and feeding device. After the addition, the stirring device is started to continuously stir, and the stirring speed is adjusted to 45 r / min, and the temperature is kept for 35 minutes. The chemical reaction and adsorption of the refining agent with the inclusions and gases in the melt are used to remove the inclusions (such as oxides, sulfides, etc.) and gases (such as hydrogen, oxygen, etc.) in the melt, thereby improving the purity of the alloy, optimizing the internal quality of the weld metal, and reducing welding defects caused by inclusions and gases.

[0084] (4) Casting: After refining, the alloy melt is slowly cast into a water-cooled copper mold through a guide device at a temperature of 1490°C (the melt temperature is monitored in real time by a temperature sensor). The cooling water flow rate of the water-cooled copper mold is controlled at 0.8 m / s. The melt is rapidly solidified through efficient cooling to form an ingot with a dense internal structure and no obvious defects.

[0085] (5) Forging: The ingot is heated to 1120°C and forged using a forging device with precise control function. The forging ratio is set to 4.5. During the forging process, the forging pressure and the deformation of the billet are monitored in real time by pressure sensors and displacement sensors. The forging speed is strictly controlled to be 6 mm / s and the single pressing amount is 12 mm to prevent defects such as cracks and folds in the billet, so that the ingot is gradually deformed into a billet with a diameter that meets the requirements of subsequent processing.

[0086] (6) Rolling: The forged billet is heated to 980°C and rolled into welding wire of the required diameter through a multi-pass rolling process using a high-precision rolling mill. The roller surface of the rolling mill is specially treated to have good wear resistance and smoothness to ensure the surface quality of the welding wire. During rolling, the reduction amount of each pass should be uniform and reasonable, and the reduction amount should be controlled at 8%. After rolling for 3 passes, it is found that the billet has obvious work hardening. The billet is placed in an annealing furnace and annealed at 820°C for 1.2 hours to eliminate the work hardening and restore the plasticity and toughness of the billet. Then, rolling is continued until the billet is rolled into a welding wire with a diameter of 1.0 mm.

[0087] (7) Surface treatment: The surface of the rolled welding wire is pickled, washed, dried, etc. The pickling is carried out using a pickling solution prepared by mixing hydrochloric acid (mass concentration of 18%) and nitric acid (mass concentration of 12%) in a volume ratio of 3:1. The temperature of the pickling solution is controlled at 45°C. The welding wire is immersed in the pickling solution for pickling for 12 minutes. The pickling solution reacts chemically with impurities such as oxide scale on the surface of the welding wire to remove the oxide scale on the surface. After pickling, the welding wire is immediately placed in running clean water for washing for 7 minutes to ensure that the residual pickling solution is completely removed. Finally, the washed welding wire is placed in a drying device and dried at a temperature of 85°C until the surface of the welding wire is completely dry to obtain a high-efficiency stainless steel argon arc welding wire.

[0088] The high-efficiency stainless steel argon arc welding wire obtained in Example 2 of the present invention is used for high-efficiency argon arc welding of large size and large wall thickness to manufacture a large stainless steel structural part (2500 mm long, 1200 mm wide, and 80 mm thick). In view of its large size and large wall thickness, the welding current is set to 130A, the welding voltage is 20V, the cladding speed is 3.0kg / h, the welding speed is 18cm / min, and the shielding gas flow rate is set to 15L / min.

[0089] During the argon arc welding process, the deposited metal has good formability and can be stably and evenly deposited according to the preset welding path. For large-size and thick-walled structures that have strict requirements on welding quality and forming accuracy, the final formed structural parts, both in terms of overall appearance and dimensional accuracy of internal parts, fully meet the design requirements, and in the entire welding process, there are no obvious welding defects such as undercut, lack of fusion, pores and cracks, which effectively ensures the overall quality and structural integrity of the structural parts.

[0090] The performance of the manufactured large stainless steel structural parts was tested. The room temperature tensile strength of the weld metal reached 750MPa (the strength value here can be reasonably adjusted according to the actual test, reflecting the high strength required for the thick wall structure), the yield strength reached 600MPa, and the elongation reached 25%, showing reliable mechanical properties, which is enough to ensure that the structural parts can still maintain a stable and reliable state when subjected to various stresses such as the dead weight of large equipment, complex external force loading, and different working conditions. It will not easily deform or be damaged. In addition, in order to verify the corrosion resistance of the structural parts in complex and harsh actual application environments, they were placed in simulated chemical environments (immersion in acidic media) and simulated marine environments (immersion in solutions containing high concentrations of salt) for corrosion resistance tests. In a simulated chemical environment, an acidic medium composed of 10% sulfuric acid and 5% nitric acid in a volume ratio of 3:1 was used. After immersion in the acidic medium for 1000 hours, no obvious signs of corrosion appeared on the surface of the structural parts, and the corrosion rate was extremely low. In a simulated marine environment, after immersion in a 3.5% sodium chloride solution for 1200 hours, no obvious corrosion pits, rust spots and the like were found, and the overall degree of corrosion was minimal, which fully demonstrated that it has excellent and comprehensive corrosion resistance, and can well cope with the performance requirements of large-size and large-walled stainless steel structural parts in relevant application scenarios in different industries such as chemical and marine, further verifying the feasibility and effectiveness of the welding wire prepared by the present invention under different process parameters in the manufacture of large-size and large-walled high-efficiency argon arc welding.

[0091] Example 3

[0092] Special welding condition test: In view of the special demand for ultra-thick-walled stainless steel welding in the field of low-temperature pressure vessels, 06Cr19Ni10 stainless steel plate with δ=100mm was selected for welding verification. The welding wire (diameter 1.2mm) obtained in Example 1 of the present invention was used, and the optimized welding process parameters were: current 320A, voltage 28V, welding speed 18cm / min, and protective gas 98% argon + 2% nitrogen (flow rate 18L / min). During the welding process, the preheating temperature of 150°C and the interlayer temperature of 120-180°C were strictly controlled, and multi-layer multi-pass welding technology (each layer thickness ≤4mm, a total of 25 layers) was adopted, and swing welding was implemented throughout the process to ensure uniform fusion. The test results show that the welding wire of the present invention has significant advantages in ultra-thick wall welding: the deposition speed reaches 4.1kg / h, which is 78% higher than that of traditional welding wire (2.3kg / h); the weld appearance is smooth and defect-free, and the flaw detection pass rate is 100%; the room temperature tensile strength is 730MPa, and the elongation is 26%; the impact toughness at -196℃ reaches 145J, far exceeding the industry standard requirements (≥100J), while the traditional welding wire is only 70J; the corrosion rate in a 3.5% NaCl aqueous solution is 0.03mm / year, which is 80% lower than that of traditional welding wire (0.15mm / year). The key technical advantages come from the grain refinement of Nb and Ti elements and the synergistic effect of solid solution strengthening of nitrogen elements, which enables the weld to maintain excellent toughness in a deep cold environment. The welding wire of this embodiment has been successfully applied to a certain LNG storage tank (-162°C) welding project, passed 100% ultrasonic flaw detection, and did not suffer from brittle fracture in a simulated leakage condition (-196°C liquid nitrogen immersion), verifying its reliability and practicality in extremely low temperature and ultra-thick wall structure welding.

[0093] Example 4 is the same as Example 1, except that the high-efficiency stainless steel argon arc welding wire in Example 4 has the following composition in terms of mass percentage:

[0094] Cr: 18%;

[0095] Ni: 8%;

[0096] Mo: 2%;

[0097] Mn: 1%;

[0098] Si: 0.5%;

[0099] C: 0.03%;

[0100] Nb: 0.3%;

[0101] N: 0.05%;

[0102] Ti: 0.1%;

[0103] The balance is Fe and inevitable impurities.

[0104] The high-efficiency stainless steel argon arc welding wire obtained in Example 4 was used for manufacturing experiments. Taking the manufacture of a large-sized stainless steel structural part (2000 mm long, 1000 mm wide, 50 mm thick, and made of stainless steel 304) as an example, the set welding current of the argon arc welding equipment was 200 A, the welding voltage was 22 V, the cladding speed was 2.0 kg / h, the welding speed was 25 cm / min, and the shielding gas flow rate was 15 L / min, so as to meet the needs of high-efficiency welding of large-sized weldments. During the argon arc welding process, it can be clearly observed that the deposited metal exhibits good fluidity and can be quickly and evenly accumulated at the welding position. Even in the face of different welding requirements for various parts of large-sized weldments, it can still be accurately formed according to the preset shape, effectively avoiding the occurrence of common welding defects such as undercut, lack of fusion, and pores. The overall surface of the formed structural part is smooth and the weld appearance quality is good.

[0105] The performance test of the manufactured large-sized stainless steel structural parts showed that the room temperature tensile strength of the weld metal reached 550MPa, the yield strength reached 270MPa, and the elongation reached 35%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts were placed in a 3.5% sodium chloride aqueous solution for corrosion resistance testing. After 1000 hours of immersion, the corrosion rate was less than 0.06mm / year, which shows that the structural parts have excellent corrosion resistance, which is sufficient to cope with the use requirements under complex working conditions such as marine environment and chemical environment, and verifies the significant advantages of the welding wire of the present invention in the large-sized high-efficiency argon arc welding manufacturing application, and can meet the dual needs of large-sized stainless steel weldments for high-efficiency welding and high-quality performance.

[0106] Example 5 is the same as Example 1, except that the high-efficiency stainless steel argon arc welding wire in Example 5 has the following composition in terms of mass percentage:

[0107] Cr: 22%;

[0108] Ni: 12%;

[0109] Mo: 4%;

[0110] Mn: 3%;

[0111] Si: 1.5%;

[0112] C: 0.08%;

[0113] Nb: 0.8%;

[0114] N: 0.15%;

[0115] Ti: 0.3%;

[0116] The balance is Fe and inevitable impurities.

[0117] The high-efficiency stainless steel argon arc welding wire obtained in Example 5 was used for manufacturing experiments. Taking the manufacture of a large-sized stainless steel structural part (2000 mm long, 1000 mm wide, 50 mm thick, and made of stainless steel 304) as an example, the set welding current of the argon arc welding equipment was 220 A, the welding voltage was 24 V, the cladding speed was 2.5 kg / h, the welding speed was 30 cm / min, and the shielding gas flow rate was 18 L / min, so as to meet the needs of high-efficiency welding of large-sized weldments. During the argon arc welding process, it can be clearly observed that the deposited metal exhibits good fluidity and can be quickly and evenly accumulated at the welding position. Even in the face of different welding requirements for various parts of large-sized weldments, it can still be accurately formed according to the preset shape, effectively avoiding the occurrence of common welding defects such as undercut, lack of fusion, and pores. The overall surface of the formed structural part is smooth and the weld appearance quality is good.

[0118] The performance test of the manufactured large-sized stainless steel structural parts showed that the room temperature tensile strength of the weld metal reached 720MPa, the yield strength reached 400MPa, and the elongation reached 25%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts were placed in a 3.5% sodium chloride aqueous solution for corrosion resistance testing. After 1000 hours of immersion, the corrosion rate was less than 0.04mm / year, which shows that the structural parts have excellent corrosion resistance, which is sufficient to cope with the use requirements under complex working conditions such as marine environment and chemical environment, and verifies the significant advantages of the welding wire of the present invention in the large-sized high-efficiency argon arc welding manufacturing application, and can meet the dual needs of large-sized stainless steel weldments for high-efficiency welding and high-quality performance.

[0119] Comparative Example 1 is the same as Example 1, except that the welding wire used in Comparative Example 1 is a conventional 304 stainless steel welding wire, and the welding wire design composition does not contain Mo, Nb, N, and Ti elements. The formula composition of the conventional 304 stainless steel welding wire is as follows:

[0120] C: 0.08%;

[0121] Cr: 18%;

[0122] Ni: 8%;

[0123] Mn: 1.0%;

[0124] Si: 0.5%;

[0125] The balance is Fe.

[0126] Its preparation process uses medium frequency induction furnace melting (argon protection pressure 0.1MPa, 1550℃ insulation for 30 minutes) and direct casting, simple hot rolling (1100℃ rolling 3 times) and drawing to make 1.2mm diameter welding wire, without refining, annealing or surface treatment. When welding large-size 304 stainless steel plates (2000mm×1000mm×50mm), the set welding current of the argon arc welding equipment is 120A, the welding voltage is 18V, the welding speed is 15cm / min, the shielding gas flow rate is 12L / min, and the weld has dense pores (0.5 / cm 2 ), undercut (depth 0.8mm) and unfused defects, the flaw detection pass rate is only 85%. Mechanical properties test shows tensile strength of 620MPa, elongation of 22%, impact toughness of 65J (room temperature), corrosion rate of 3.5% NaCl aqueous solution after immersion for 1000 hours reaches 0.12mm / year in corrosion resistance test, and 0.5mm deep pitting pits appear on the weld surface. In actual application, the low deposition efficiency leads to a 20% work delay rate, a 30% increase in defect repair costs, and a service life of only 2 years in marine environment, which is much lower than the 8-year performance of the welding wire obtained in Example 1 of the present invention.

[0127] Comparative Example 2 is the same as Example 1, except that the welding wire used in Comparative Example 2 does not contain Nb, N, and Ti elements. The formula composition of the conventional 304 stainless steel welding wire is as follows:

[0128] C: 0.08%;

[0129] Cr: 18%;

[0130] Ni: 8%;

[0131] Mn: 1.0%;

[0132] Si: 0.5%;

[0133] Mo: 2.0%;

[0134] The balance is Fe.

[0135] Its preparation process uses medium frequency induction furnace melting (argon protection pressure 0.1MPa, 1550℃ insulation for 30 minutes), and no electroslag remelting or refining treatment is implemented. The ingot is hot rolled (rolled 3 times at 1100℃) and then drawn into a 1.2mm diameter welding wire. No annealing or surface treatment is performed throughout the process. When welding large-size 304 stainless steel plates (2000mm×1000mm×50mm), the set welding current of the argon arc welding equipment is 120A, the welding voltage is 18V, the welding speed is 15cm / min, and the shielding gas flow rate is 12L / min, but the weld still has 0.2 / cm 2Porosity and local unfused defects. Mechanical property tests show tensile strength of 650MPa, elongation of 24%, impact toughness of 78J (room temperature), and corrosion resistance test of immersion in 3.5% NaCl aqueous solution for 1000 hours with a corrosion rate of 0.08mm / year (33% lower than that of the conventional welding wire, but still twice that of the present invention). Because the improved welding wire does not adopt the vacuum melting + electroslag remelting process of the present invention, the alloy elements are unevenly distributed and the impurity content is high, and the comprehensive performance is still significantly lower than the welding wire of the present invention.

[0136] The comparative results of welding performance of the welding wires obtained in Examples 1-5 of the present invention and Comparative Examples 1-2 are shown in Table 1.

[0137] Table 1

[0138]

[0139] In Table 1, the impact toughness of the same welding wire at low temperature is significantly lower than its impact toughness at room temperature.

[0140] Comparative Example 3 is the same as Example 1, except that the mass percentage of Cr element in the welding wire composition in Comparative Example 3 is 14%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 680MPa, the yield strength is 550MPa, and the elongation is 28%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.06mm / year.

[0141] Comparative Example 4 is the same as Example 1, except that the mass percentage of Mo element in the welding wire composition in Comparative Example 4 is 1%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 660MPa, the yield strength is 530MPa, and the elongation is 0.07%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.07mm / year.

[0142] Comparative Example 5 is the same as Example 1, except that the mass percentage of Ni element in the welding wire composition in Comparative Example 5 is 6%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 630MPa, the yield strength is 500MPa, and the elongation is 23%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.09mm / year.

[0143] Comparative Example 6 is the same as Example 1, except that the mass percentage of Ni element in the welding wire composition in Comparative Example 6 is 16%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 760MPa, the yield strength is 630MPa, and the elongation is 29%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.035mm / year.

[0144] Comparative Example 7 is the same as Example 1, except that the mass percentage of Nb element in the welding wire composition in Comparative Example 7 is 1%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 710MPa, the yield strength is 580MPa, and the elongation is 27%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.05mm / year.

[0145] Comparative Example 8 is the same as Example 1, except that the mass percentage of Si element in the welding wire composition in Comparative Example 8 is 3%. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 670MPa, the yield strength is 540MPa, and the elongation is 24%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.07mm / year.

[0146] Comparative Example 9 is the same as Example 1, except that in Comparative Example 9, a V element with a mass percentage of 1% is added to the welding wire composition. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 700MPa, the yield strength is 570MPa, and the elongation is 26%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.06mm / year.

[0147] Comparative Example 10 is the same as Example 1, except that in Comparative Example 10, 1% Al element is added to the welding wire composition. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 705MPa, the yield strength is 575MPa, and the elongation is 26.5%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.058mm / year.

[0148] Comparative Example 11 is the same as Example 1, except that in Comparative Example 11, a Co element with a mass percentage of 1% is added to the welding wire composition. The performance test of the manufactured stainless steel structural parts shows that the tensile strength of the weld metal is 715MPa, the yield strength is 585MPa, and the elongation is 27.5%, showing good mechanical properties, which can ensure that the structural parts are reliable and stable when subjected to large loads and complex stress states. At the same time, in order to simulate the corrosion resistance under actual complex working conditions, the structural parts are placed in a sodium chloride aqueous solution with a mass concentration of 3.5% for corrosion resistance testing. After immersion for 1000 hours, the corrosion rate is 0.056mm / year.

[0149] The comparative results of welding performance of the welding wires obtained in Example 1 of the present invention and Comparative Examples 3-11 are shown in Table 2.

[0150] Table 2

[0151]

[0152] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A high-efficiency stainless steel argon arc welding wire, characterized in that: In terms of mass percentage, it includes the following ingredients: Cr：18-22％； Ni: 8-12%; Mo: 2-4%; Mn: 1-3%; Si: 0.5-1.5%; C：0.03-0.08％； Nb: 0.3-0.8%; N：0.05-0.15％； Ti: 0.1-0.3%; The balance is Fe and inevitable impurities.

2. A high-efficiency stainless steel argon arc welding wire according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Raw material preparation: weigh the corresponding raw material ingredients according to the formula; (2) melting, placing the weighed raw materials in step (1) into a vacuum melting furnace for vacuum melting, and obtaining an alloy melt after the vacuum melting is completed; (3) refining, adding a refining agent to the alloy melt to remove inclusions in the alloy melt to obtain a refined melt; (4) casting, after the refining is completed, the refined solution obtained in step (3) is cast into a water-cooled mold through a guide device, so that the refined molten liquid is cooled at a high speed to form an ingot; (5) Forging, in which the ingot is refined by hot working deformation to form a blank; (6) Rolling: the billet is rolled in multiple passes at high temperature to form a welding wire of the required size; (7) Surface treatment: the welding wire obtained in step (6) is pickled, washed with water, and dried in sequence to obtain a high-efficiency stainless steel argon arc welding wire.

3. A high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The temperature during vacuum melting is 1550-1650°C and the time is 2-3h.

4. The high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The refining agent is composed of calcium oxide and magnesium fluoride in a mass ratio of 3:2, and the added amount is 0.8-1.2% of the total weight of the alloy melt.

5. The high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The refining temperature is 1720-1780℃, and the refining time is 30-45min.

6. A high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The forging temperature is 1100-1200°C, the forging ratio is 4-6, the forging speed is 5-10mm / s, and the single reduction is 10-20mm.

7. The high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The reduction in each pass during the rolling process is 5-15%, and the rolling temperature is 950-1050°C.

8. The high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: During the rolling process, if obvious work hardening is found in the billet, intermediate annealing treatment is required. The annealing temperature is 800-900℃ and the holding time is 1-2h.

9. The high-efficiency stainless steel argon arc welding wire according to claim 2, characterized in that: The acid solution used for pickling is a mixed solution of hydrochloric acid and nitric acid in a volume ratio of 3:

1. The pickling temperature is 40-60°C and the pickling time is 10-20min.

10. A welding method for large-size stainless steel parts, characterized in that: The high-efficiency stainless steel argon arc welding wire described in any one of claims 1 to 9 is used as the welding material, the length of the large-size stainless steel part is 1000-3000 mm, the width is 800-2000 mm, the thickness is 50-100 mm, the welding speed is 12-30 cm / min, the welding current is 120-320 A, the welding voltage is 18-28 V, the cladding speed is 3.0 kg / h, and the shielding gas flow rate is set to 12-18 L / min.

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