An 800MPa-grade underwater marine additive repair welding wire and its production, use and evaluation method

Abstract

The present invention relates to an 800MPa-grade marine underwater additive repair welding wire and a production, use and evaluation method thereof. The chemical composition of the welding wire is as follows by weight: C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance is Fe and unavoidable impurity elements; the invention adds The addition of rare earth element Ce increases the fluidity of the molten pool, improves the post-weld forming effect, and strengthens the bonding between the repair body and the additive body. Ce oxide promotes the nucleation of acicular ferrite, effectively reducing the hardened structure during underwater additive repair. Physical and chemical methods are used to remove the iron oxide scale on the surface of the wire rod. The welding wire produced by multiple wire drawing and annealing processes makes the deposited metal after welding have good corrosion resistance and cutting performance, which is more suitable for fine weld repair. The yield strength reaches ≥690MPa, the tensile strength reaches ≥800MPa, and the impact resistance at ‑40℃ is not less than 47J.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater additive repair materials, and in particular to an 800MPa-grade marine underwater additive repair welding wire and a production, use and evaluation method thereof. Background Art

[0002] Since the beginning of the 21st century, my country's marine engineering and shipbuilding industries have made breakthrough progress, with the scale of the industry increasing significantly, the quality of its products being widely recognized, and the country occupying an important position internationally. With the accelerated development of marine resources, the construction of marine engineering facilities such as warships, offshore oil platforms, submarine oil pipelines, and cross-sea bridges has increased year by year. These marine engineering structures are extremely prone to damage due to their long-term operation in the marine environment and the harsh service environment. In addition, the main parts of marine engineering structures are underwater, making inspection and replacement after damage difficult and expensive. Once major structural damage or capsizing occurs, it will cause serious loss of life and property. Therefore, in the event of damage, it is extremely important to implement underwater emergency repairs and restore the function of the damaged structure as soon as possible. Faced with the changing and complex marine service environment, marine engineering steel must indirectly have high strength, high toughness, good weldability, and resistance to seawater corrosion.

[0003] Underwater in-situ repair technology is a key technology for repairing marine engineering equipment and is also a necessary technical means. Therefore, the production and welding application of underwater repair welding wire are particularly important. There are many problems in the production and use of traditional welding wire. For example, due to the many requirements for the mechanical properties of the welding wire, a variety of alloy elements are added during the forging process, but the cost of adding alloy elements is high. Due to the complexity of the underwater environment, cold cracks are prone to occur in the deposited metal during underwater welding. Due to the high melting point of the welding wire, a preheating process is required before welding. The fluidity of the welding pool cannot be accurately controlled during the welding process, and the forming rate after welding cannot be guaranteed.

[0004] The Chinese patent application number CN202010456165 proposes a welding technology for 800MPa-grade low-alloy steel gas shielded welding wire. It fully considers the crack resistance, strength and toughness of the weld metal, designs the alloy content of the appropriate system, and reduces the alloy cost. However, this process cannot guarantee the fluidity of the molten pool, and the forming rate after welding cannot be guaranteed.

[0005] Chinese patent application number CN202310690568 proposes a nickel-based alloy welding wire and its preparation method. By adopting electroslag remelting, blank forging and heat treatment preparation processes, it can effectively reduce the content of harmful elements such as sulfur and phosphorus in the alloy, improve the impurity distribution of the alloy, and facilitate the refinement of the structure, thereby improving its hot working performance and yield rate. However, this welding wire does not fully consider the underwater environment and has no clear requirements for gas protection.

[0006] Chinese patent application number CN201910778749 proposes a metal wire for underwater additive repair in marine engineering. Considering the complexity of the underwater environment, the process is improved by adding alloying elements to improve the hardenability and corrosion resistance of the deposited metal. It can combine with C to precipitate in the deposited metal and limit the migration of carbon atoms during post-weld heat treatment to prevent the formation of strip ferrite. However, the welding wire used cannot prevent the generation of gas during the welding process, and the floating of gas affects the welding effect.

[0007] Chinese patent application number CN201710216082 proposes a solid welding wire for high-strength steel arc welding. This process ensures stable arc, small welding spatter and welding smoke during welding, and the tensile strength of the deposited metal can reach ≥650MPa. However, underwater welding is not possible and there is no gas protection.

[0008] There are some technical problems in the production and use of existing welding wires in the ocean. For example, adding alloy elements during the smelting process will increase production costs. In the face of finer welds, the diameter of the welding wire produced by current technology cannot be applied. In addition, due to the complex underwater environment, the welding wire produced by existing technology cannot fully adapt to welding wire repair, and the fluidity of the welding pool and the forming rate after welding cannot be accurately controlled during the welding process. Therefore, in order to meet people's urgent requirements for high performance and wide range of uses, developing a good welding wire process is one of the key technical problems that need to be solved today. Since in-situ repair is extremely difficult in the extreme environment of high pressure, high humidity and high cooling rate underwater, it is urgent to explore the production process and application scope of underwater additive repair welding wire from the source of the material, and with appropriate auxiliary measures, develop a welding wire and corresponding welding process suitable for underwater additive repair in marine engineering. Summary of the Invention

[0009] The present invention provides an 800MPa-grade marine underwater additive repair welding wire and its production, use and evaluation method. The yield strength reaches ≥690MPa, the tensile strength reaches ≥800MPa, and the impact resistance at -40°C is not less than 47J, realizing underwater additive repair welding wire and a corresponding underwater local dry arc additive repair process.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] An 800MPa-grade marine underwater additive repair welding wire has the following chemical compositions by weight: C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance being Fe and unavoidable impurity elements.

[0012] A method for producing an 800MPa-grade underwater marine additive repair welding wire comprises the following steps:

[0013] S1, vacuum induction melting:

[0014] S2. Forging the alloy ingot into an alloy billet;

[0015] S3. Rolling: The alloy billet is rolled to ensure that the wire rod structure is ferrite + pearlite, avoiding the bainite region, and the ferrite transformation start temperature is controlled at 820-840°C, and the pearlite transformation end temperature is controlled at 600-620°C;

[0016] S4. Pickling: The wire rod is pretreated by combining mechanical and chemical methods. First, a double-drum scale remover is used to remove the iron oxide scale attached to the surface of the hot-rolled wire rod. Then, a chemical method, alkaline boiling-pickling composite method, is used. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank containing a mixture of sodium hydroxide and sodium nitrate and heated for alkaline boiling for 1.5 to 2 hours. Then, the iron oxide scale is removed by pickling. After alkaline boiling, the steel is immediately immersed in a water tank to remove the iron oxide scale. The soaked wire is then placed in a treatment tank containing sulfuric acid, nitric acid, and hydrochloric acid for 1 to 1.5 hours and further pickled to remove the iron oxide scale.

[0017] S5. Annealing and wire drawing: After the wire drawing process, the wire rod is annealed and then wire drawing is performed. The wire drawing process is divided into three steps: coarse wire drawing, medium wire drawing and fine wire drawing. Coarse wire drawing is to draw the wire rod into 4.0-4.5 mm and then anneal it; medium wire drawing is to draw it to 2.1-2.5 mm and then anneal it again; fine wire drawing is to draw it to 0.8-1.5 mm; finally, the wire is copper plated.

[0018] Furthermore, step S1 adopts vacuum induction melting, which specifically includes removing surface defects and impurities of the required raw material low S, P steel ingots, adding the treated alloy ingots into a medium frequency vacuum induction heating furnace for heating, the power of the heating furnace is 50-90KW, turning on the vacuum system, and heating the system to 1540-1690°C at a heating rate of 5-15°C / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 100-120 rpm, and the vacuum is evacuated to 0.3-0.7MPa. The required elements are added according to the composition requirements, the electromagnetic stirring speed is adjusted to 150-300 rpm, and ultrasonic vibration is turned on at the same time. After the temperature reaches 1400-1550°C, it is kept warm for 2-4 hours, and the content of alloy elements and impurity components is measured again to ensure the composition content.

[0019] Furthermore, step S1 adopts vacuum induction melting. In the vacuum induction melting process, after the alloy ingot is placed in the melting furnace, the pretreated Ce-containing alloy or ore is added to the furnace. The pretreatment process is as follows: first, the Ce-containing fluorocarbon cerium ore is placed in a chlorine environment, the fluorocarbon cerium ore is burned in the chlorine environment to produce an alloy containing cerium trichloride, and then the cerium trichloride-containing alloy is placed in an electrolytic cell to obtain an alloy containing cerium element by electrolysis.

[0020] Furthermore, step S1 adopts vacuum induction melting, and the alloy ingot is deoxidized after the process. Inert gas is blown into the molten metal pool at a temperature of 1450-1550°C to cause a carbon-oxygen reaction, thereby reducing the partial pressure of CO gas and causing the reaction to proceed in the forward direction, thereby performing deoxidation.

[0021] Furthermore, the double-drum iron remover includes a motor box, a conveying device, a wire rod transport box, a horizontal hexagonal drum, a vertical cylindrical drum, an impurity collecting device, a horizontal connecting shaft and a vertical connecting shaft. The upper part of the motor box is connected to the transmission device through a belt, and the wire rod transport box conveys the wire rod to the horizontal hexagonal drum and the vertical cylindrical drum for processing in turn through the transmission device. The horizontal hexagonal drum is connected to the motor box through a horizontal connecting shaft, and the vertical cylindrical drum is connected to the motor box through a vertical connecting shaft.

[0022] Furthermore, the double-drum iron remover conveys the smelted wire rod to the horizontal hexagonal drum through a conveying device for horizontal rotation, sets the rotation speed to 20-30 rad / s, takes out the wire rod after working for 25-30 minutes, and transports it to the vertical cylindrical drum through a transmission device for vertical rotation, sets the rotation speed to 30-40 rad / s, and transports the wire rod out by the conveying device after working for 25-30 minutes.

[0023] Furthermore, after the rough wire drawing, a recrystallization annealing process is adopted, the wire rod is heated to 650-550°C, kept warm for 25-35 minutes, and then cooled with the furnace to eliminate stress and soften the wire rod. Subsequently, after the medium wire drawing, a stress relief annealing process is adopted, the wire rod is heated to 500-400°C, kept warm for 20-30 minutes, and cooled in air to eliminate internal stress again and soften the wire rod.

[0024] A method for using an 800MPa-grade underwater marine additive repair welding wire specifically comprises: sending a welding wire repair device and a gas collection device to a depth of 20 to 30 meters underwater, adopting an underwater local dry arc cladding welding process, opening the nozzle of the gas collection device when the welding wire approaches the weld to be repaired, and releasing gas to displace water around the arc, with a gas flow rate of 16 to 18 L / min. During the welding process, the welding equipment, the welding wire, and the weld are placed in a mixed gas protection environment, the mixed gas used being composed of inert shielding gas Ar gas and oxygen, the welding current being 250 to 270A, the welding voltage being 27 to 29V, the welding speed being 0.5 to 0.6cm / s, and the welding line energy being 14 to 16kJ / cm2 TIG heat input being selected until the welding process is completed, closing the gas nozzle after completion, and sending the welding wire repair device and the gas collection device out of the water using a control device.

[0025] An evaluation method for an 800MPa-grade underwater marine additive repair welding wire comprises the following steps:

[0026] (1) Detection of the mechanical properties of the deposited metal: Take samples from the weld seam and measure the yield strength, tensile strength and impact toughness using a metal material testing machine;

[0027] (2) Corrosion resistance test of deposited metal at weld seam: After welding, take a deposited metal sample at the weld seam, take some seawater around the weld seam to simulate the liquid environment of seawater, measure the temperature and underwater pressure at 20 meters underwater, put the taken seawater test solution into a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, put the obtained deposited metal sample into the pressure vessel, observe for one month, take out the sample after observation, and observe the number of corrosion pits, depth and size of corrosion pits through metallographic pictures;

[0028] (3) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, cut with the same thickness, observe the cutting resistance displayed by the equipment and use the roughness tester to test the roughness of the metal surface after cutting.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1) Adding rare earth element Ce during the smelting process improves the fluidity of the molten pool and the post-weld forming rate, meeting the dual effect requirements of the root weld and the build-up weld. In addition, the oxides of Ce and Ti formed will promote the formation of acicular ferrite and improve the structure and properties of the deposited metal;

[0031] 2) Physical and chemical methods are used during the pickling process to loosen the remaining iron oxide scale, which is beneficial to accelerate the chemical reaction speed during pickling and can completely remove the iron oxide scale on the surface of the wire rod;

[0032] 3) Due to the use of welding wire produced by multiple wire drawing and annealing processes, the deposited metal after welding has relatively good corrosion resistance and cutting performance, which can well meet the milling requirements of underwater additive manufacturing components and reduce the diameter of the welding wire, making it suitable for more precise processing and weld repair;

[0033] 4) The yield strength reaches ≥690MPa, the tensile strength reaches ≥800MPa, and the impact at -40℃ is not less than 47J. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the underwater single-layer multi-channel repair according to the present invention.

[0035] Figure 2 It is a schematic diagram of the multi-layer repair forming of the welding wire according to the present invention.

[0036] Figure 3 It is a structural schematic diagram of the double-drum iron remover of the present invention.

[0037] Figure: 1. Motor box 2. Conveyor 3. Wire rod transport box 4. Horizontal hexagonal roller 5. Vertical cylindrical roller 6. Impurity collector 7. Horizontal connecting shaft 8. Vertical connecting shaft DETAILED DESCRIPTION

[0038] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0039] The present invention discloses an 800MPa-grade marine underwater additive repair welding wire, whose chemical composition by weight is as follows: C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance is Fe and unavoidable impurity elements.

[0040] C: As the most important strengthening element, C can significantly improve the strength of the weld metal through solid solution strengthening. However, too high a C content will increase the hardenability of the weld, increase the cold crack sensitivity of the weld metal, and affect the toughness of the weld metal. Especially during the underwater repair process, the large repair component body will increase the cooling rate of the weld metal, making it more likely to produce hardenable structure and cold cracks. Therefore, the present invention adopts the principle of low C content design supplemented by other structure control methods to achieve the purpose of ensuring the strength and toughness of the additive component. The C content is controlled at 0.03-0.09%.

[0041] Si: Si is an important deoxidizing element in welding wire. It can form SiO2 with O. When the ratio of Si and Mn elements is appropriate, a good deoxidation effect can be achieved. In addition, Si can also improve the fluidity of the molten pool of weld metal and improve the forming effect of underwater additive components. However, if the Si content is too high, the toughness of the additive components will deteriorate. At the same time, too high Si content will affect the corrosion resistance of the underwater additive repair metal. Therefore, the Si content is controlled to ≤0.15%.

[0042] Mn: Mn is also a deoxidizer, which can form a Si-Mn combined deoxidation effect with Si to improve the deoxidation ability. Mn can act as a solid solution strengthening component to improve the strength of the weld. When the Mn content is too low, deoxidation is insufficient during the droplet transfer and molten pool reaction stages, resulting in excessively high oxygen content in the weld. When the Mn content is too high, the segregation of the Mn element will form the MA component, significantly reducing the low-temperature impact toughness of the additive component. Therefore, the Mn content is controlled at 1.0-2.0%.

[0043] P and S elements: P and S elements will reduce the toughness of the weld metal and significantly reduce the toughness of the additive component. Therefore, the content of P and S elements must be strictly controlled, with P element controlled at <0.004% and S element controlled at <0.004%.

[0044] Ni: Ni can not only improve the strength of the weld metal, but also improve the low-temperature toughness of the weld metal and significantly reduce the ductile-brittle transition temperature. Ni plays an important role in the microstructure and performance requirements of underwater additive repair welding wires. Ni can promote the transformation of austenite to acicular ferrite. However, Ni is a relatively expensive metal. Taking into full consideration the economic and functional requirements, the Ni content is controlled in the range of 2.5-4.5%.

[0045] Cu: The Cu element has two functions in the present invention. First, it can improve the corrosion resistance of the additive component. The Cu element can activate the anode and make the steel produce cathode passivation. In addition, the dissolved Cu+ can form Cu2S with S2- particles and adsorb on the surface of the additive component to slow down the occurrence of corrosion. Second, Cu will form some Cu-rich phases in the additive component. These Cu-rich phases can play a lubricating role in the subsequent processing of the additive component and improve the milling efficiency of the additive component. However, too high a Cu content will increase the hardenability and further worsen the disadvantage of the large cooling rate of underwater additive. Therefore, the Cu content is controlled at 0.15-0.30%.

[0046] Ti: Ti element can form oxide Ti2O3 with O element. Ti2O3 is recognized in the field of oxides to promote the formation of intracrystalline acicular ferrite, thereby reducing the tendency to form martensite due to excessive cooling rate, which helps to improve the strength and toughness of underwater additive repair components. In addition, there will be a stress field around these oxides, which can interact with hydrogen atoms and adsorb hydrogen around, forming a trap to capture hydrogen, reducing the crack sensitivity of underwater additive repair components and effectively reducing the occurrence of hydrogen-induced cracking. However, too high a Ti content will also affect the low-temperature toughness of the additive component. Therefore, the Ti content is controlled at 0.010-0.025%.

[0047] O: The O element is generally a harmful element mixed in during the smelting process. If there is a large amount of O element in the welding wire steel, oxides will easily form in the welding wire steel. These oxides will serve as a source of fracture during the wire rod rolling and drawing process, affecting the processability of rolling and drawing. Especially for additive welding wire, the welding wire of the present invention is required to be drawn to 1.0 mm, so the control of the O element is also extremely important. Therefore, the content of the O element is controlled to ≤0.005%.

[0048] Ce: Rare earth element Ce can reduce surface tension and improve the fluidity of the molten pool. Since the cooling rate is high during underwater additive repair, it is not conducive to the flow of the molten pool. Adding an appropriate amount of rare earth element Ce can act as a surfactant, increase the wettability of the molten pool, and improve the flow effect of the molten pool. When making the base weld, it can show the characteristics of increased penetration depth, which can increase the interfacial bonding strength between the additive body and the parent material. When making the height weld, it can show the expansion of the melt width direction, improve the forming of additive repair components, and meet the dual effect requirements of the base weld and the height weld of marine steel with a yield strength of 690MPa. At the same time, the rare earth element Ce has a strong affinity with O and S, and the oxides formed can also act as heterogeneous nucleation particles to promote the formation of acicular ferrite and reduce crack sensitivity. However, too much rare earth element can easily cause poor metallurgical reactions. Therefore, the Ce content is controlled at 0.001~0.01%.

[0049] Rare earth elements added to welding wire can also increase the fluidity of the molten pool. Figure 1 As shown in the schematic diagram of underwater single-layer multi-pass repair, the penetration depth can be increased in the root weld. During the root weld repair process, the single-layer multi-pass welding process will make the transition interface present a wavy distribution, increasing the interface bonding strength, such as Figure 2 As shown in the schematic diagram of the multi-layer repair forming process of welding wire, the excellent molten pool fluidity during the stacking process can also improve the transition behavior between passes, achieving a smoother transition between passes, which is beneficial to the forming control of the welding wire during the underwater additive repair process and improving the formability of the repaired component.

[0050] A method for producing an 800MPa-grade underwater marine additive repair welding wire comprises the following steps:

[0051] S1. Use vacuum induction melting: Surface treatment is performed on the required raw material low S, P steel to remove surface defects and impurities. An ethanol solution with a mass fraction higher than 65% is used for treatment to remove surface dust and impurity particles. The treated alloy ingot is first added to the furnace and heated by a medium frequency vacuum induction heating furnace with a power of 50Kw to 90Kw. The vacuum system is turned on and the system is heated to 1540-1690°C at a heating rate of 5-15°C / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 100-120 rpm. The vacuum is evacuated to 0.3-0.7MPa. The required elements are added according to the composition requirements. The electromagnetic stirring speed is adjusted to 150-300 rpm. At the same time, the Ultrasonic vibration, after the temperature reaches 1400-1550℃, keep it warm for 2-4 hours, and measure the content of alloy elements and impurities again to ensure that the composition contains C: 0.03-0.09%, Si: ≤0.15%, Mn: 1.0-2.0%, P <0.004%, S <0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O ≤0.005%, Ce: 0.001-0.01%, and the balance is Fe and unavoidable impurity elements. After meeting the requirements, it is prepared for casting. Due to the vacuum environment, the [C]-[O] reaction in the molten steel can be promoted to continue by reducing the partial pressure of CO gas, and this reaction is used to achieve the purpose of deoxidation;

[0052] In the S1 vacuum induction melting process, after the alloy ingot is placed in the melting furnace, an alloy or ore containing Ce needs to be added to the furnace. Since some irrelevant elements or other impurities in the ore or alloy may affect the melting effect, the alloy or ore needs to be pretreated before adding the alloying elements. First, the Ce-containing fluorocarbon cerium ore is placed in a chlorine environment, and the fluorocarbon cerium ore is burned in the chlorine environment to produce an alloy containing cerium trichloride. The alloy containing cerium trichloride is then placed in an electrolytic cell and electrolyzed to obtain an alloy containing the cerium element, which is then added to the melting furnace.

[0053] After the S1 vacuum melting process, the alloy ingot needs to be deoxidized. Inert gas such as helium is blown into the molten metal pool at a temperature of 1450-1550°C to cause a carbon-oxygen reaction, reduce the partial pressure of CO gas, and make the reaction proceed in the forward direction, thereby achieving the purpose of deoxidation.

[0054] S2. Forging the alloy ingot into an alloy billet;

[0055] S3. Rolling: The alloy billet is rolled and the strength of the welding wire is controlled by a controlled cooling process. After the rolling process, in order to ensure that the welding wire steel wire rod has a lower tensile strength, it is necessary to slow cool at 30-50°C / min after rolling to ensure that the wire rod structure is ferrite + pearlite, avoiding the bainite area. Therefore, the ferrite start transformation temperature is controlled at 820-840°C, and the pearlite transformation end temperature is 600-620°C.

[0056] S4. Pickling: The wire rod is pretreated by combining mechanical and chemical methods. First, a mechanical method is used to use a double-drum cleaner to remove the iron oxide scale attached to the surface of the hot-rolled wire rod, and the remaining iron oxide scale is loosened, which is conducive to accelerating the chemical reaction speed during chemical treatment and can completely remove the iron oxide scale on the surface of the wire rod. The chemical method adopts an alkali boiling-pickling composite method. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank filled with a mixture of sodium hydroxide and sodium nitrate and heated for alkali boiling for 2 hours. The alkali boiling loosens the iron oxide scale, and then the pickling method is used to remove the iron oxide scale. The steel after alkali boiling is immediately immersed in a water tank to blast off the iron oxide scale, and then the soaked wire is placed in a treatment tank filled with sulfuric acid + nitric acid + hydrochloric acid, soaked for 1 hour, and further pickled to remove the iron oxide scale.

[0057] S5. Annealing and wire drawing: After the wire drawing process, the wire rod is annealed and then wire drawing is performed. In order to improve the use environment of the welding wire and enable the welding wire to weld small welds, the wire drawing process is divided into three steps: coarse wire drawing, medium wire drawing and fine wire drawing. The coarse wire drawing draws the wire rod into 4.0mm and then anneals it. After the coarse wire drawing, the recrystallization annealing process is used to eliminate the work hardening, heat it to 650-550℃, keep it warm for 25 minutes, and then cool it with the furnace. , eliminating stress and softening the wire rod; the medium wire drawing is drawn to 2.1mm, and annealing treatment is performed again. A stress relief annealing process is adopted to heat the wire rod to 500-400°C, keep warm for 20 minutes, and cool in the air to eliminate internal stress again to soften the wire rod, creating conditions for the final fine wire drawing treatment; the fine wire drawing is drawn to 1.0mm; finally, the wire is copper-plated to obtain a 1.0mm diameter 800MPa underwater additive repair welding wire for marine engineering.

[0058] See Figure 3 The double-drum iron remover includes a motor box, a conveyor, a wire rod transport box, a horizontal hexagonal drum, a vertical cylindrical drum, an impurity collecting device, a horizontal connecting shaft and a vertical connecting shaft, the upper part of the motor box is connected to the transmission device by a belt, and the wire rod transport box conveys the wire rod to the horizontal hexagonal drum and the vertical cylindrical drum for processing in turn through the transmission device, the horizontal hexagonal drum is connected to the motor box through a horizontal connecting shaft, and the vertical cylindrical drum is connected to the motor box through a vertical connecting shaft; the horizontal hexagonal drum is a horizontal horizontal drum, and the vertical cylindrical drum is a vertical vertical drum, and an impurity collecting device is respectively arranged on the outside of the horizontal hexagonal drum and the vertical cylindrical drum, and the double-drum iron remover conveys the smelted wire rod to the horizontal hexagonal drum through the conveyor for horizontal rotation, and the speed is set to 20-30 rad / s. After working for 25-30 minutes, the wire rod is taken out and transported to the vertical cylindrical drum through the transmission device for vertical rotation, and the speed is set to 30-40 rad / s. After working for 25-30 minutes, the wire rod is transported out by the conveyor.

[0059] A method for using an 800MPa-grade underwater marine additive repair welding wire comprises the following steps: using a control device to send a welding wire repair device and a gas collection device to 20 meters underwater, and adopting an underwater local dry arc cladding welding process; when the welding wire approaches the weld to be repaired, the nozzle of the gas collection device is opened, and the released gas displaces the water around the arc; the gas flow rate is 16 to 18 L / min; during the welding process, the welding equipment, welding wire, and weld are placed in a mixed gas protection environment; the mixed gas used is composed of inert protective gas Ar gas and oxygen; because excessive oxygen will increase the porosity defects during the welding process, a mixed gas of 98% Ar + 2% O2 is finally used for welding, and oxygen is used as an active gas. On the one hand, gas can produce the Marangoni effect, increase the fluidity of the molten pool, and is more conducive to the floating of pores during underwater additive repair, thereby ensuring welding quality; the welding current is 250-270A, the welding voltage is 27-29V, and the welding speed is 0.5-0.6cm / s. Compared with the traditional TIG heat input, 9-12KJ / cm is generally used. However, in the underwater additive repair process, we choose a relatively high TIG heat input, with a welding line energy of 14-16KJ / cm, to reduce the tendency of welding cold cracks and the generation of hardened structure due to excessive cooling rate until the welding process is completed. After the completion, the gas nozzle is closed, and the welding wire repair equipment and gas collection device are sent out of the water using the control equipment.

[0060] An evaluation method for an 800MPa-grade underwater marine additive repair welding wire comprises the following steps:

[0061] (4) Detection of the mechanical properties of the deposited metal: Take samples from the weld seam after welding and measure the yield strength, tensile strength and impact toughness using a metal material testing machine;

[0062] (5) Corrosion resistance test of deposited metal at weld seam: After welding, take a deposited metal sample at the weld seam, take some seawater around the weld seam to simulate the liquid environment of seawater, measure the temperature and underwater pressure at 20 meters underwater, put the taken seawater test solution into a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, put the obtained deposited metal sample into the pressure vessel, observe for one month, take out the sample after observation, and observe the number of corrosion pits, depth and size of corrosion pits through metallographic pictures;

[0063] (6) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, cut with the same thickness, observe the cutting resistance displayed by the equipment, and use the roughness tester to test the roughness of the metal surface after cutting.

[0064] The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0065] [Example 1]

[0066] The required raw material low S, P steel is surface treated to remove surface defects and impurities, and an ethanol solution with a mass fraction higher than 65% is used for treatment to remove surface dust and impurity particles. The treated alloy ingot is first added to the furnace and heated by a medium frequency vacuum induction heating furnace with a power of 65KW; the vacuum system is turned on and the system is heated to 1600℃ at a heating rate of 10℃ / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 100 rpm, and the vacuum is evacuated to 0.4MPa. The required elements are added according to the composition requirements. The alloy ingot was prepared by stirring at 1480°C for 3 hours to ensure that the composition contained C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance was Fe and unavoidable impurity elements.

[0067] The element composition of the final welding wire of Example 1 is shown in Table 1.

[0068] Table 1 Chemical element composition of welding wire (mass percentage)

[0069]

[0070] After meeting the requirements, it is prepared for casting. Due to the vacuum environment, the [C]-[O] reaction in the molten steel can be continued by reducing the partial pressure of CO gas. This reaction is used to achieve the purpose of deoxidation. The alloy ingot is forged into an alloy billet, and then the alloy billet is rolled. The welding wire strength is regulated by a controlled cooling process. In the pickling process, a combination of mechanical and chemical methods is used to pretreat the wire rod. First, a mechanical method is used to use a double-drum iron scale remover to remove the iron oxide attached to the surface of the hot-rolled wire rod, and the remaining iron oxide scale is loosened, which is conducive to accelerating the chemical reaction speed during chemical treatment and can completely remove the iron oxide on the surface of the wire rod. The chemical method adopts an alkali boiling-pickling composite method. After the wire rod is rolled and cooled to room temperature, it is placed in a mixed solution of sodium hydroxide and sodium nitrate. The steel is heated in a processing tank and alkali boiled for 2 hours. Alkali boiling can loosen the iron oxide scale, and then the iron oxide scale is removed by pickling. The steel after alkali boiling is immediately immersed in a water tank to blast off the iron oxide scale, and then the soaked wire rod is placed in a processing tank containing sulfuric acid + nitric acid + hydrochloric acid, soaked for 1 hour, and further pickled to remove the iron oxide scale. After the wire drawing process, the wire rod is annealed and then wire drawing is performed. In order to improve the use environment of the welding wire and enable the welding wire to weld small welds, the wire drawing process is divided into three steps: coarse drawing, drawing the wire rod into 4.0mm, followed by annealing, medium drawing, drawing to 2.1mm, annealing again, fine drawing, drawing to 1.0mm, and finally, copper plating of the wire is performed to obtain a 800MPa underwater additive repair welding wire for marine engineering with a diameter of 1.0mm.

[0071] The welding wire repair equipment and gas collection device are sent 20 meters underwater through the control equipment, and the underwater local dry arc cladding welding process is adopted. When the welding wire is close to the weld to be repaired, the nozzle of the gas collection device is opened, and the released gas displaces the water around the arc. The gas flow rate is 18L / min. During the welding process, the welding equipment, welding wire and weld are placed in a mixed gas protection environment. The welding current is 260A, the welding voltage is 29V, and the welding speed is 0.5cm / s until the welding process is completed. After the end, the gas nozzle is closed and the welding wire repair equipment and gas collection device are sent underwater by the control equipment. The mixed gas used is composed of inert protective gas Ar gas and oxygen. Since too much oxygen will increase the porosity defects in the welding process, the mixed gas 98% Ar+2% O2 protection environment is finally used for welding, and the welding line energy is 15KJ / cm.

[0072] The evaluation of the produced 800MPa-grade underwater marine additive repair welding wire was carried out. The specific steps include:

[0073] (1) Testing the mechanical properties of the deposited metal: Three groups of welded specimens were taken from the weld seam and the yield strength, tensile strength and impact toughness were measured using a metal material testing machine. The test results are shown in Table 2.

[0074] Table 2 Mechanical properties of sample deposited metal

[0075]

[0076] (2) Corrosion resistance test of deposited metal at weld seam: After welding, two deposited metal samples were taken from the weld seam. Some seawater around the weld seam was taken to simulate the liquid environment of seawater. The temperature at 20 meters underwater was 10°C and the underwater pressure was 2.8×10 5 MPa, the taken out seawater test solution was placed in a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, and the deposited metal sample was placed in it and observed for one month. After the observation, the sample was taken out and the number of corrosion pits, depth and size of corrosion pits were observed through metallographic pictures. The test results are shown in Table 3.

[0077] Table 3 Corrosion resistance parameters of samples

[0078]

[0079] (3) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, and cut it with the same thickness. Observe the cutting resistance displayed by the equipment and use the roughness tester to test the roughness of the metal surface after cutting. The test results are shown in Table 4.

[0080] Table 4 Cutting performance parameters of samples

[0081]

[0082] [Example 2]

[0083] The required raw material low S, P steel is surface treated to remove surface defects and impurities, and an ethanol solution with a mass fraction higher than 65% is used for treatment to remove surface dust and impurity particles. The treated alloy ingot is first added to the furnace and heated by a medium frequency vacuum induction heating furnace with a power of 70Kw; the vacuum system is turned on and the system is heated to 1620℃ at a heating rate of 12℃ / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 120 rpm, and the vacuum is evacuated to 0.55MPa. The required Elements, the electromagnetic stirring speed is adjusted to 210 rpm, and ultrasonic vibration is turned on at the same time. After the temperature reaches 1490°C and is kept warm for 2 hours, the alloy ingot is measured again to ensure that the composition contains C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance is Fe and unavoidable impurity elements.

[0084] The elemental composition of the final welding wire of Example 2 is shown in Table 5.

[0085] Table 5 Chemical element composition of welding wire (mass percentage)

[0086]

[0087] After meeting the requirements, it is prepared for casting. Since it is in a vacuum environment, the CO reaction in the molten steel can be continued by reducing the partial pressure of CO gas. This reaction is used to achieve the purpose of deoxidation. The alloy ingot is forged into an alloy billet, and then the alloy billet is rolled. The welding wire strength is regulated by a controlled cooling process. In the pickling process, a combination of mechanical and chemical methods is used to pretreat the wire rod. First, a mechanical method is used to use a double-drum iron scale remover to remove the iron oxide attached to the surface of the hot-rolled wire rod, and the remaining iron oxide scale is loosened, which is conducive to accelerating the chemical reaction speed during chemical treatment and can completely remove the iron oxide on the surface of the wire rod. The chemical method adopts an alkali boiling-pickling composite method. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank containing a mixed alkali solution of sodium hydroxide and sodium nitrate. Heat and alkali boil for 2 hours, alkali boiling can loosen the iron oxide scale, and then use pickling to remove the iron oxide scale. After alkali boiling, the steel is immediately immersed in a water tank to blast off the iron oxide scale, and then the soaked wire is placed in a treatment tank filled with sulfuric acid + nitric acid + hydrochloric acid, soaked for 1 hour, and further pickled to remove the iron oxide scale. After the wire drawing process, the wire rod is annealed and then wire drawing is performed. Since the use environment of the welding wire is improved and the welding wire can weld small welds, the wire drawing process of the welding wire is divided into three steps: coarse drawing, drawing the wire rod into 4.0mm, followed by annealing, medium drawing, drawing to 2.1mm, annealing again, fine drawing, drawing to 1.0mm, and finally, copper plating of the wire is performed to obtain 800MPa underwater additive repair welding wire for marine engineering with a diameter of 1.0mm.

[0088] The welding wire repair equipment and gas collection device are sent 20 meters underwater through the control equipment, and the underwater local dry arc cladding welding process is adopted. When the welding wire is close to the weld to be repaired, the nozzle of the gas collection device is opened, and the released gas displaces the water around the arc. The gas flow rate is 18L / min. During the welding process, the welding equipment, welding wire and weld are placed in a mixed gas protection environment. The welding current is 256A, the welding voltage is 29V, and the welding speed is 0.5cm / s until the welding process is completed. After the end, the gas nozzle is closed and the welding wire repair equipment and gas collection device are sent underwater by the control equipment. The mixed gas used is composed of inert protective gas Ar gas and oxygen. Since too much oxygen will increase the porosity defects in the welding process, the mixed gas 98% Ar+2% O2 protection environment is finally used for welding, and the welding line energy is 14.8KJ / cm.

[0089] The evaluation of the produced 800MPa-grade underwater marine additive repair welding wire was carried out. The specific steps include:

[0090] (1) Testing the mechanical properties of the deposited metal: Three groups of welded specimens were taken at the weld seam and the yield strength, tensile strength and impact toughness were measured using a metal material testing machine. The test results are shown in Table 6.

[0091] Table 6 Mechanical properties of deposited metal

[0092]

[0093] (2) Corrosion resistance test of deposited metal at weld seam: After welding, two deposited metal samples were taken from the weld seam. Some seawater around the weld seam was taken to simulate the liquid environment of seawater. The temperature at 20 meters underwater was 10°C and the underwater pressure was 2.8×10 5 MPa, the taken out seawater test solution was placed in a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, and the deposited metal sample was placed in it and observed for one month. After the observation, the sample was taken out and the number of corrosion pits, depth and size of corrosion pits were observed through metallographic pictures. The test results are shown in Table 7.

[0094] Table 7 Corrosion resistance parameters of samples

[0095]

[0096] (3) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, and cut it with the same thickness. Observe the cutting resistance displayed by the equipment and use the roughness tester to test the roughness of the metal surface after cutting. The test results are shown in Table 8.

[0097] Table 8 Cutting performance parameters of samples

[0098]

[0099] [Example 3]

[0100] The required raw material low S, P steel is surface treated to remove surface defects and impurities, and an ethanol solution with a mass fraction higher than 65% is used for treatment to remove surface dust and impurity particles. The treated alloy ingot is first added to the furnace and heated by a medium frequency vacuum induction heating furnace. The power of the heating furnace is 78Kw, and the power output is adjusted according to specific needs; the vacuum system is turned on, and the system is heated to 1650℃ at a heating rate of 14℃ / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 115 rpm, and the vacuum is evacuated to 0.6MPa. The required elements were added, and the electromagnetic stirring speed was adjusted to 200 rpm. Ultrasonic vibration was also activated. After the temperature reached 1500°C, it was held for 3.5 hours. The alloy ingot was then retested to ensure that the composition contained C: 0.03-0.09%, Si ≤ 0.15%, Mn: 1.0-2.0%, P < 0.004%, S < 0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O ≤ 0.005%, Ce: 0.001-0.01%, and the balance was Fe and unavoidable impurities. The elemental composition of the final welding wire of Example 1 is shown in Table 9.

[0101] Table 9 Chemical element composition of welding wire (mass percentage)

[0102]

[0103] After meeting the requirements, it is prepared for casting. Since it is in a vacuum environment, the CO reaction in the molten steel can be continued by reducing the partial pressure of CO gas. This reaction is used to achieve the purpose of deoxidation. The alloy ingot is forged into an alloy billet, and then the alloy billet is rolled. The welding wire strength is regulated by a controlled cooling process. In the pickling process, a combination of mechanical and chemical methods is used to pretreat the wire rod. First, a mechanical method is used to use a double-drum iron scale remover to remove the iron oxide attached to the surface of the hot-rolled wire rod, and the remaining iron oxide scale is loosened, which is conducive to accelerating the chemical reaction speed during chemical treatment and can completely remove the iron oxide on the surface of the wire rod. The chemical method adopts an alkali boiling-pickling composite method. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank containing a mixed alkali solution of sodium hydroxide and sodium nitrate. Heat and alkali boil for 2 hours, alkali boiling can loosen the iron oxide scale, and then use pickling to remove the iron oxide scale. After alkali boiling, the steel is immediately immersed in a water tank to blast off the iron oxide scale, and then the soaked wire is placed in a treatment tank filled with sulfuric acid + nitric acid + hydrochloric acid, soaked for 1 hour, and further pickled to remove the iron oxide scale. After the wire drawing process, the wire rod is annealed and then wire drawing is performed. Since the use environment of the welding wire is improved and the welding wire can weld small welds, the wire drawing process of the welding wire is divided into three steps: coarse drawing, drawing the wire rod into 4.0mm, followed by annealing, medium drawing, drawing to 2.1mm, annealing again, fine drawing, drawing to 1.0mm, and finally, copper plating of the wire is performed to obtain 800MPa underwater additive repair welding wire for marine engineering with a diameter of 1.0mm.

[0104] The welding wire repair equipment and gas collection device are sent 20 meters underwater through the control equipment, and the underwater local dry arc cladding welding process is adopted. When the welding wire is close to the weld to be repaired, the nozzle of the gas collection device is opened, and the released gas displaces the water around the arc. The gas flow rate is 17L / min. During the welding process, the welding equipment, welding wire and weld are placed in a mixed gas protection environment. The welding current is 264A, the welding voltage is 28V, and the welding speed is 0.5cm / s until the welding process is completed. After the end, the gas nozzle is closed and the welding wire repair equipment and gas collection device are sent underwater by the control equipment. The mixed gas used is composed of inert protective gas Ar gas and oxygen. Since too much oxygen will increase the porosity defects in the welding process, the mixed gas 98% Ar+2% O2 protection environment is finally used for welding, and the welding line energy is 14.7KJ / cm.

[0105] The evaluation of the produced 800MPa-grade underwater marine additive repair welding wire was carried out. The specific steps include:

[0106] (1) Testing the mechanical properties of the deposited metal: Three groups of welded specimens were taken from the weld seam and the yield strength, tensile strength and impact toughness were measured using a metal material testing machine. The test results are shown in Table 10.

[0107] Table 10 Mechanical properties of deposited metal

[0108]

[0109] (2) Corrosion resistance test of deposited metal at weld seam: After welding, two deposited metal samples were taken from the weld seam. Some seawater around the weld seam was taken to simulate the liquid environment of seawater. The temperature at 20 meters underwater was 10°C and the underwater pressure was 2.8×10 5 MPa, the taken out seawater test solution was placed in a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, and the deposited metal sample was placed in it and observed for one month. After the observation, the sample was taken out and the number of corrosion pits, depth and size of corrosion pits were observed through metallographic pictures. The test results are shown in Table 11.

[0110] Table 11 Corrosion resistance parameters of samples

[0111]

[0112] (3) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, and cut it with the same thickness. Observe the cutting resistance displayed by the equipment and use the roughness tester to test the roughness of the metal surface after cutting. The test results are shown in Table 12.

[0113] Table 12 Sample cutting performance parameters

[0114]

[0115] [Example 4]

[0116] The required raw material low S, P steel is surface treated to remove surface defects and impurities, and an ethanol solution with a mass fraction higher than 65% is used for treatment to remove surface dust and impurity particles. The treated alloy ingot is first added to the furnace and heated by a medium frequency vacuum induction heating furnace. The power of the heating furnace is between 80Kw, and the power output is adjusted according to specific needs; the vacuum system is turned on, and the system is heated to 1650℃ at a heating rate of 10℃ / min while continuously evacuating the vacuum. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 120 rpm, and the vacuum is evacuated to 0.7MPa. The composition requires the addition of required elements, the electromagnetic stirring speed is adjusted to 300 rpm, and the ultrasonic vibration is turned on at the same time. After the temperature reaches 1550°C, it is kept warm for 4 hours, and the alloy ingot is measured again to ensure that the composition contains C: 0.03-0.09%, Si≤0.15%, Mn: 1.0-2.0%, P<0.004%, S<0.004%, Ni: 2.5-4.5%, Cu: 0.15-0.30%, Ti: 0.010-0.025%, O≤0.005%, Ce: 0.001-0.01%, and the balance is Fe and unavoidable impurity elements.

[0117] The elemental composition of the final welding wire of Example 1 is shown in Table 13.

[0118] Table 13 Chemical element composition of welding wire (mass percentage)

[0119]

[0120] After meeting the requirements, it is prepared for casting. Due to the vacuum environment, the CO reaction in the molten steel can be continued by reducing the partial pressure of CO gas, and this reaction is used to achieve the purpose of deoxidation. The alloy ingot is forged into an alloy billet, and then the alloy billet is rolled. The welding wire strength is controlled by the controlled cooling process. In the pickling process, a combination of mechanical and chemical methods is used to pre-treat the wire rod. First, a mechanical method is used to use a double-drum iron scale remover to remove the iron oxide attached to the surface of the hot-rolled wire rod, and the remaining iron oxide scale is loosened, which is conducive to accelerating the chemical reaction speed during chemical treatment and can completely remove the iron oxide on the surface of the wire rod. The chemical method adopts an alkali boiling-pickling composite method. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank containing a mixed alkali solution of sodium hydroxide and sodium nitrate. Heat and alkali boil for 2 hours, alkali boiling can loosen the iron oxide scale, and then use pickling to remove the iron oxide scale. After alkali boiling, the steel is immediately immersed in a water tank to blast off the iron oxide scale, and then the soaked wire is placed in a treatment tank filled with sulfuric acid + nitric acid + hydrochloric acid, soaked for 1 hour, and further pickled to remove the iron oxide scale. After the wire drawing process, the wire rod is annealed and then wire drawing is performed. Since the use environment of the welding wire is improved and the welding wire can weld small welds, the wire drawing process of the welding wire is divided into three steps: coarse drawing, drawing the wire rod into 4.0mm, followed by annealing, medium drawing, drawing to 2.1mm, annealing again, fine drawing, drawing to 1.0mm, and finally, copper plating of the wire is performed to obtain 800MPa underwater additive repair welding wire for marine engineering with a diameter of 1.0mm.

[0121] The welding wire repair equipment and gas collection device are sent 20 meters underwater through the control equipment, and the underwater local dry arc cladding welding process is adopted. When the welding wire is close to the weld to be repaired, the nozzle of the gas collection device is opened, and the released gas displaces the water around the arc. The gas flow rate is 18L / min. During the welding process, the welding equipment, welding wire and weld are placed in a mixed gas protection environment. The welding current is 265A, the welding voltage is 29V, and the welding speed is 0.5cm / s until the welding process is completed. After the end, the gas nozzle is closed and the welding wire repair equipment and gas collection device are sent underwater by the control equipment. The mixed gas used is composed of inert protective gas Ar gas and oxygen. Since too much oxygen will increase the porosity defects in the welding process, the mixed gas 98% Ar+2% O2 protection environment is finally used for welding, and the welding line energy is 15.3KJ / cm.

[0122] The evaluation of the produced 800MPa-grade underwater marine additive repair welding wire was carried out. The specific steps include:

[0123] (1) Testing the mechanical properties of the deposited metal: Three groups of welded specimens were taken from the weld seam and the yield strength, tensile strength and impact toughness were measured using a metal material testing machine. The test results are shown in Table 14.

[0124] Table 14 Mechanical properties of deposited metal

[0125]

[0126] (2) Corrosion resistance test of deposited metal at weld seam: After welding, two deposited metal samples were taken from the weld seam. Some seawater around the weld seam was taken to simulate the liquid environment of seawater. The temperature at 20 meters underwater was 10°C and the underwater pressure was 2.8×10 5 MPa, the taken out seawater test solution was placed in a constant temperature and pressure pressure vessel at 20 meters underwater simulating seawater, and the deposited metal sample was placed in it and observed for one month. After the observation, the sample was taken out and the number of corrosion pits, depth and size of corrosion pits were observed through metallographic pictures. The test results are shown in Table 15.

[0127] Table 15 Corrosion resistance parameters of samples

[0128]

[0129] (3) Cutting test: Take the cutting sample as the upper corrosion-resistant deposited metal sample, place the obtained sample on the cutting machine, and cut it with the same thickness. Observe the cutting resistance displayed by the equipment and use the roughness tester to test the roughness of the metal surface after cutting. The test results are shown in Table 16.

[0130] Table 16 Sample cutting performance parameters

[0131]

Claims

1. A method for producing an 800MPa-grade underwater marine additive repair welding wire, characterized in that: The specific steps include: S1, using vacuum induction melting; S2. Forging the alloy ingot into an alloy billet; S3. Rolling: The alloy billet is rolled to ensure that the wire rod structure is ferrite + pearlite, avoiding the bainite region, and the ferrite transformation start temperature is controlled at 820-840°C, and the pearlite transformation end temperature is controlled at 600-620°C; S4. Pickling: The wire rod is pretreated by combining mechanical and chemical methods. First, a double-drum scale remover is used to remove the iron oxide scale attached to the surface of the hot-rolled wire rod. Then, a chemical method, alkaline boiling-pickling combined method, is used. After the wire rod is rolled and cooled to room temperature, it is placed in a treatment tank containing a mixture of sodium hydroxide and sodium nitrate and heated for alkaline boiling for 1.5 to 2 hours. Then, the iron oxide scale is removed by pickling. After alkaline boiling, the steel is immediately immersed in a water tank to remove the iron oxide scale. The soaked wire is then placed in a treatment tank containing sulfuric acid, nitric acid, and hydrochloric acid for 1 to 1.5 hours and further pickled to remove the iron oxide scale. S5. Annealing and wire drawing: After the wire drawing process, the wire rod is annealed and then wire drawing is performed. The wire drawing process is divided into three steps: coarse wire drawing, medium wire drawing and fine wire drawing. Coarse wire drawing is to draw the wire rod into 4.0-4.5 mm and then anneal it; medium wire drawing is to draw it to 2.1-2.5 mm and then anneal it again; fine wire drawing is to draw it to 0.8-1.5 mm; finally, the wire is copper plated.

2. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 1, characterized in that: The step S1 adopts vacuum induction melting, which specifically includes: The surface defects and impurities of the required raw material low S, P steel ingot are removed, and the treated alloy ingot is added to a medium frequency vacuum induction heating furnace for heating. The power of the heating furnace is 50 to 90 kW. The vacuum system is turned on, and the system is heated to 1540 to 1690°C at a heating rate of 5 to 15°C / min while continuously evacuating. After the temperature is reached, electromagnetic stirring is turned on at a stirring speed of 100 to 120 rpm. The vacuum is evacuated to 0.3 to 0.7 MPa, and the required elements are added according to the composition requirements. The electromagnetic stirring speed is adjusted to 150 to 300 rpm. At the same time, ultrasonic vibration is turned on. After the temperature reaches 1400 to 1550°C, it is kept warm for 2 to 4 hours, and the content of alloy elements and impurity components is measured again to ensure the composition content.

3. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 1, characterized in that: Step S1 adopts vacuum induction melting. In the vacuum induction melting process, after the alloy ingot is placed in a melting furnace, a pretreated Ce-containing alloy or ore is added to the furnace. The pretreatment process is as follows: first, the Ce-containing fluorocarbon cerium ore is placed in a chlorine environment, the fluorocarbon cerium ore is burned in the chlorine environment to produce an alloy containing cerium trichloride, and then the cerium trichloride-containing alloy is placed in an electrolytic cell to obtain an alloy containing the cerium element through electrolysis.

4. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 1, characterized in that: The step S1 adopts vacuum induction melting, and the alloy ingot is deoxidized after the process. Inert gas is blown into the molten metal pool at a temperature of 1450-1550°C to cause a carbon-oxygen reaction, thereby reducing the partial pressure of CO gas and making the reaction proceed in the forward direction, thereby performing deoxidation.

5. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 1, characterized in that: The double-drum iron remover includes a motor box, a conveying device, a wire rod transport box, a horizontal hexagonal drum, a vertical cylindrical drum, an impurity collecting device, a horizontal connecting shaft and a vertical connecting shaft. The upper part of the motor box is connected to the transmission device through a belt. The wire rod transport box conveys the wire rod to the horizontal hexagonal drum and the vertical cylindrical drum for processing in turn through the transmission device. The horizontal hexagonal drum is connected to the motor box through a horizontal connecting shaft, and the vertical cylindrical drum is connected to the motor box through a vertical connecting shaft.

6. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 5, characterized in that: The double-drum iron remover conveys the smelted wire rod to the horizontal hexagonal drum through a conveying device for horizontal rotation, and sets the speed to 20-30 rad / s. After working for 25-30 minutes, the wire rod is taken out and transported to the vertical cylindrical drum through a transmission device for vertical rotation, and sets the speed to 30-40 rad / s. After working for 25-30 minutes, the wire rod is transported out by the conveying device.

7. The method for producing an 800MPa-grade underwater marine additive repair welding wire according to claim 1, characterized in that: After the rough drawing, a recrystallization annealing process is adopted, the wire rod is heated to 650-550°C, kept warm for 25-35 minutes, and then cooled with the furnace to eliminate stress and soften the wire rod. Subsequently, after the medium drawing, a stress relief annealing process is adopted, the wire rod is heated to 500-400°C, kept warm for 20-30 minutes, and cooled in air to eliminate internal stress again and soften the wire rod.

Images