Intergranular corrosion resistant 5B06 seamless aluminum pipe for surface ship and preparation method of intergranular corrosion resistant 5B06 seamless aluminum pipe

Abstract

The invention relates to the field of aluminum alloy seamless pipes, and particularly discloses an intergranular corrosion resistant 5B06 seamless aluminum pipe for a surface ship and a preparation method thereof, and the preparation method comprises the following steps: smelting, standing after refining, casting, and hot extrusion and cold rolling: extruding an aluminum alloy round cast rod into a seamless pipe in an extruder, and cleaning the surface after step quenching, and then the aluminum pipe is subjected to cold rolling, uniform annealing is conducted in a homogenizing furnace, stable aging treatment is conducted after heat treatment, and the seamless aluminum pipe subjected to heat treatment is straightened, inspected and put in storage. According to the preparation process, nickel, zirconium and scandium can be promoted to diffuse to form a corrosion-resistant phase, carbide compound precipitation and solute solid solution are promoted, the crystal lattice direction is changed, stress is effectively eliminated, the intergranular corrosion resistance of the aluminum pipe can be effectively improved, and the comprehensive mechanical property of the aluminum pipe can be effectively adjusted; quenching sensitivity is reduced, and recrystallization is inhibited; the prepared pipe is uniform in wall thickness, free of defect damage, excellent in performance and high in grain boundary corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aluminum alloy seamless pipes, and particularly relates to a 5B06 seamless aluminum pipe with intergranular corrosion resistance for surface warships and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy materials are widely used in various industries, especially in the marine transportation industry, due to their excellent properties such as low density and high activity. However, due to the high reactivity and poor corrosion resistance of aluminum alloys, they are easily corroded by seawater. Currently, the most commonly used Al-Mg alloy for marine applications has good corrosion resistance, such as 5B06, which is an Al-Mg-Si aluminum alloy widely used in the aerospace and shipbuilding industries. It is suitable for high-salt environments and has high strength and is not easily deformed. The magnesium content is usually between 1.0-1.6%, and a magnesium content of more than 1% will increase the risk of intergranular corrosion by enriching at the grain boundaries. Intergranular corrosion is a type of localized corrosion that occurs when the interface between metal grains expands inward. It is mainly caused by differences in chemical composition between the grain surface and the interior, as well as the presence of impurities or internal stress at the grain boundaries. The degree of grain bonding decreases, making it easy to break at the grain boundaries and damage the mechanical properties of the metal. Common causes include the formation of carbide or oxide precipitates, metal lattice strain, etc. Currently, there are two ways to reduce the risk of corrosion: alloy modification and process improvement. Adding transition metal elements can improve the performance of the alloy. Transition metals are dispersed in the alloy to form alloy phases, which can increase the recrystallization temperature of the alloy. For example, adding 1% zirconium and scandium can reduce the risk of intergranular corrosion. Increasing the annealing temperature of the material can also improve its corrosion resistance. However, transition metals such as scandium are expensive, and zirconium is easily oxidized to form oxides that affect the performance of the alloy. Current processes do not significantly improve intergranular corrosion resistance, and the resulting pipe material is difficult to use in corrosive environments for a long time.

[0003] Patent CN202011261796.8 discloses a production process for aluminum alloy seamless pipes for aerospace, which includes melting, refining, homogenization heat treatment, extrusion, and heat treatment. The product has good corrosion resistance, no coarse recrystallization structure, and no overburning. However, carbon tetrachloride is used for refining, which can produce byproducts and cause damage to equipment. Patent CN117431441B discloses a high-purity high-performance aluminum alloy seamless pipe for the nuclear industry and a preparation method thereof. The mechanical properties are good, but the alloy composition is complex, and radioactive elements are added. The corrosion resistance of the resulting seamless pipe is not high, and it is not suitable for general corrosive environments. SUMMARY

[0004] To solve the above problems, the present application provides a 5B06 seamless aluminum pipe with intergranular corrosion resistance for surface warships and a preparation method thereof.

[0005] The technical content of the present application is as follows: The present application provides a preparation method of 5B06 seamless aluminum pipe material for water surface warship, comprising the following steps: Step 1: smelting and refining: all raw materials are prepared according to the amount, aluminum material and Mg, Si and Mn are heated to a temperature of 700-800℃ and kept for 10-20min, then Zr, Sc and Ni are added to increase the temperature to 1000-1100℃ and kept for 5-10min, and then refined and placed; The refining is carried out in argon containing refining agent at a temperature of 1000-1100℃ for 8-12min, and then refined in argon at a temperature of 700-800℃ for 6-8min, and then vacuum circulation degassing; The amount of the refining agent is 0.1-0.2% of the molten liquid, which is composed of nano-silicon dioxide, silane, dopamine and magnesium chloride with a mass ratio of 0.5-2.5:0.1-0.4:1-3:1-3; effectively reduces the impurity content and improves the intergranular corrosion performance; through smelting and refining, the alloy is fully crystallized, the utilization rate of transition metal is improved, and the low-temperature precipitates carbide is reduced; The holding time of the standing is 4-10min; Step 2: casting: pouring into ingot at a temperature of 700-800℃; Step 3: hot extrusion and cold rolling: preheating the aluminum alloy round casting bar to 500-550℃, extruding into seamless pipe material in the extruder, then cleaning the surface after grading quenching, then cold rolling the aluminum pipe material, and uniformly annealing in the homogenizing furnace; The grading quenching is carried out in quenching oil at a temperature of 300-400℃, the quenching speed is 20-30℃ / min, the holding time is 2-4min, then water cooling to 200-300℃, the cooling rate is 10-20℃ / s, and then cooling to 80-120℃ under vacuum condition; Hot extrusion can change the crystal lattice direction, introduce strain, optimize the grain boundary structure performance, and effectively avoid the precipitation of one-phase compound along the grain boundary through grading strong cold quenching, and can promote solute solid solution; Then the low-frequency cold rolling is used to regulate the crystal lattice interface deformation, and the slow cooling annealing can eliminate the stress of the pipe material; The homogenizing annealing is carried out at a temperature of 400-500℃ for 0.8-1.0h, the annealing rate is 60-100℃ / h, and the heating furnace atmosphere is hydrogen atmosphere; The cold rolling is first slow cooling to a temperature of 550-600℃, and the deformation rate of cold rolling is 5-10%; Step 4: heat treatment: heating the pipe material to 800-1000℃, and then performing stable aging treatment; The stable aging treatment is to keep the pipe material at a temperature of 260-280 DEG C for 80-100 min, and then keep it at a temperature of 100-120 DEG C for 1-2 h; the low-temperature stabilization aging can promote recrystallization of the alloy material, and control the grain size during full crystallization; Step 5: straightening, testing and warehousing of the heat-treated seamless aluminum pipe.

[0006] The application also provides a 5B06 seamless aluminum pipe material for surface warships and resistant to intergranular corrosion, which comprises the following components: Mg 1.0-1.5%, Si 0.4-0.8%, Zr 0.1-0.25%, Sc 0.1-0.25%, Ni 0.1-0.2%, impurity content 0-0.3%, and the rest is Al. The added nickel and manganese can improve the solid solution phase, and have high reactivity and stable combination with supersaturated carbon, reduce the production of carbide, have oxidation resistance, reduce the production of oxide, reduce the reactivity of the pipe surface and the outside world, and promote the uniform diffusion of transition metal elements, reduce the zirconium-poor grain boundary and transition element like grain boundary segregation; Aluminum, magnesium, transition group alloy, main component of aluminum magnesium system is regulated by micro-alloying, transition group elements are added to form a dispersion distribution of corrosion-resistant phase, and the corrosion channel caused by grain boundary segregation is inhibited; Zr / Sc micro-alloying (0.1%-0.25%) reduces the quenching sensitivity and inhibits recrystallization. The 5B06 seamless aluminum pipe material for surface warships and resistant to intergranular corrosion comprises the following components: Mg 1.1-1.4%, Si 0.5-0.7%, Zr 0.15-0.2%, Sc 0.15-0.2%, Ni 0.12-0.18%, impurity content 0-0.3%, and the rest is Al.

[0007] The application has the following beneficial effects: the application provides a preparation method of a 5B06 seamless aluminum pipe material for surface warships and resistant to intergranular corrosion, the aluminum material and other metals are fully fused by melting and refining the material, the second phase diffusion is inhibited by using medium-high temperature during melting, then high temperature is used to promote the diffusion of nickel, zirconium and scandium to form a corrosion-resistant phase, the molten liquid is degassed by blowing argon containing a refining agent during refining, and the molten liquid is subjected to graded water quenching, quenching in quenching oil, water and vacuum conditions in sequence after hot extrusion treatment, to promote the precipitation and solubility of carbide compounds, then cold rolling is performed to change the lattice direction, and slow annealing is performed to effectively eliminate stress, the molten liquid is subjected to stable aging treatment after heat treatment, the residence time in the dangerous temperature zone is controlled, the carbon is dissolved back, the intergranular corrosion resistance is improved, overheating and rapid cooling are prevented, and the carbon cannot be precipitated; The application further provides the 5B06 seamless aluminum pipe material for water surface warships and resistant to intergranular corrosion, which is micro-alloyed by adding metals such as nickel, zirconium and scandium, nickel can improve the fluidity of alloy melt and improve the oxidation resistance, the addition of transition elements forms a dispersion distribution of corrosion-resistant phase, inhibits the corrosion channel caused by grain boundary segregation, Zr / Sc micro-alloying reduces the quenching sensitivity and inhibits recrystallization; the prepared pipe material has uniform wall thickness, no defect damage to the material body, the tensile strength of the pipe material is greater than or equal to 280 MPa, the yield strength is greater than or equal to 210 MPa, and the elongation is greater than or equal to 10%, and the performance is excellent; and the potential difference with the aluminum matrix can be reduced, the grains are uniform, the grain size is moderate, the grain size reaches 4-5 levels, the grain boundary performance is excellent, and the grain boundary corrosion resistance of the pipe material is strong. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 The preparation process flow of the 5B06 seamless aluminum pipe material of the application is shown. DETAILED DESCRIPTION

[0009] The application will be further described in detail through specific implementation examples, and it should be understood that these examples are only used to illustrate the application and not to limit the protection scope of the application, and various equivalent modifications of the application made by those skilled in the art after reading the application all fall within the claims of the application.

[0010] Unless otherwise specified, all raw materials and reagents of the application are conventional market raw materials and reagents.

[0011] The preparation process flow of the 5B06 seamless aluminum pipe material of the application is shown. Figure 1

[0012] Example 1 A preparation method of a 5B06 seamless aluminum pipe material for water surface warships and resistant to intergranular corrosion of scandium Step 1: melting and refining: all raw materials are prepared according to the amount, aluminum material and Mg, Si and Mn are heated to a temperature of 750 DEG C and kept for 15 min, then Zr, Sc and Ni are added to increase the temperature to 1050 DEG C and keep for 8 min, and then refined in argon containing 0.15% of the melt, which is composed of nano-silicon dioxide, silane, dopamine and magnesium chloride with a mass ratio of 1:0.2:2:2, at a temperature of 1050 DEG C for 10 min, and then refined in argon at a temperature of 750 DEG C for 7 min, and then vacuum circulation degassing and standing for 7 min; Step 2: casting: pouring into ingot at a temperature of 750 DEG C; ​Step 3: hot extrusion and cold rolling: the aluminum alloy round ingot is preheated to 520℃, extruded into seamless pipe in an extruder, quenched in quenching oil at a temperature of 350℃, the quenching speed is 25℃ / min, the holding time is 3min, then water cooled to 250℃, the cooling rate is 15℃ / s, then cooled to 100℃ under vacuum condition for step quenching, then surface cleaning, then slowly cooled to 570℃, cold rolling deformation rate is 8%, then cold rolling, homogenization annealing in a homogenization furnace at a temperature of 450℃, the annealing speed is 80℃ / h, the heating furnace atmosphere is hydrogen atmosphere; Step 4: heat treatment: the pipe is heated to 900℃, then held at a temperature of 270℃ for 90min, then held at 110℃ for 1h for stable aging treatment; Step 5: straightening, inspection and storage of the heat treated seamless aluminum pipe.

[0013] Example 2 A method for preparing 5B06 seamless aluminum pipe with scandium intergranular corrosion for surface ships Step 1: melting and refining: all raw materials are prepared according to the amount, aluminum material and Mg, Si, Mn are heated to a temperature of 700℃ and held for 10min, then Zr, Sc, Ni are added to increase the temperature to 1000℃ and held for 5min, then refined in argon containing 0.1% of the molten liquid, which is composed of 0.5:0.1:1:1 of nano silicon dioxide, silane, dopamine, magnesium chloride by mass ratio, at a temperature of 1000℃ for 8min, then refined in argon at a temperature of 700℃ for 6min, then vacuum circulation degassing, and then held for 4min; Step 2: casting: cast into an ingot at a temperature of 700℃; Step 3: hot extrusion and cold rolling: the aluminum alloy round ingot is preheated to 500℃, extruded into seamless pipe in an extruder, quenched in quenching oil at a temperature of 300℃, the quenching speed is 20℃ / min, the holding time is 2min, then water cooled to 200℃, the cooling rate is 10℃ / s, then cooled to 80℃ under vacuum condition for step quenching, then surface cleaning, then slowly cooled to 570℃, cold rolling deformation rate is 5%, then cold rolling, homogenization annealing in a homogenization furnace at a temperature of 400℃, the annealing speed is 60℃ / h, the heating furnace atmosphere is hydrogen atmosphere; Step 4: heat treatment: the pipe is heated to 800℃, then held at a temperature of 260℃ for 80min, then held at 100℃ for 1h for stable aging treatment; Step 5: straightening, inspection and storage of the heat treated seamless aluminum pipe.

[0014] Example 3 Preparation method of 5B06 seamless aluminum pipe material for surface warship with scandium intergranular corrosion Step 1: smelting and refining: all raw materials are prepared according to the amount, aluminum material and Mg, Si and Mn are heated to a temperature of 800 DEG C and kept for 20 min, then Zr, Sc and Ni are added to increase the temperature to 1100 DEG C and kept for 10 min, and then refined in argon containing 0.2% of the refining agent composed of nano-silicon dioxide, silane, dopamine and magnesium chloride with a mass ratio of 2.5:0.4:3:3 in the molten liquid at a temperature of 1100 DEG C for 12 min, and then refined in argon at a temperature of 800 DEG C for 8 min, and then vacuum circulation degassing is carried out, and then kept for 10 min after standing; Step 2: casting: cast into ingot at a temperature of 800 DEG C; Step 3: hot extrusion and cold rolling: the aluminum alloy round casting bar is preheated to 550 DEG C, extruded into seamless pipe material in the extruder, quenched in quenching oil at a temperature of 400 DEG C, the quenching speed is 30 DEG C / min, kept for 4 min, then water cooled to 300 DEG C, the cooling rate is 20 DEG C / s, then cooled to 120 DEG C under vacuum condition for staged quenching, then the surface is cleaned, then the aluminum pipe material is slowly cooled to a temperature of 600 DEG C, cold rolled with a deformation rate of 10%, homogenized in a homogenizing furnace at a temperature of 500 DEG C for 1.0 h, the annealing rate is 100 DEG C / h, and the heating furnace atmosphere is hydrogen atmosphere; Step 4: heat treatment: heat the pipe material to 1000 DEG C, then keep at a temperature of 280 DEG C for 100 min, then keep at 120 DEG C for 2 h for stable aging treatment; Step 5: straighten, test and store the heat treated seamless aluminum pipe material.

[0015] Example 4 Preparation method of 5B06 seamless aluminum pipe material for surface warship with scandium intergranular corrosion Step 1: smelting and refining: all raw materials are prepared according to the amount, aluminum material and Mg, Si and Mn are heated to a temperature of 700 DEG C and kept for 10 min, then Zr, Sc and Ni are added to increase the temperature to 1000 DEG C and kept for 10 min, and then refined in argon containing 0.1% of the refining agent composed of nano-silicon dioxide, silane, dopamine and magnesium chloride with a mass ratio of 0.5:0.4:1:3 in the molten liquid at a temperature of 1100 DEG C for 8 min, and then refined in argon at a temperature of 800 DEG C for 6 min, and then vacuum circulation degassing is carried out, and then kept for 10 min after standing; Step 2: casting: cast into ingot at a temperature of 700 DEG C; Step 3: Hot extrusion and cold rolling: The aluminum alloy round casting rod is preheated to 550℃ and extruded into a seamless tube in an extruder. Then, it is quenched in quenching oil at 300℃ at a quenching rate of 30℃ / min and held for 2min. Then, it is water-cooled to 300℃ at a cooling rate of 10℃ / s. Subsequently, it is cooled to 120℃ under vacuum conditions for graded quenching and surface cleaning. The aluminum tube is then slowly cooled to 550℃ and cold-rolled with a deformation rate of 10%. It is then homogenized and annealed in a homogenizing furnace at 500℃ for 0.8h at a homogenization rate of 100℃ / h. The furnace atmosphere is hydrogen. Step 4: Heat treatment: Heat the pipe to 800℃, then keep it at 280℃ for 80 minutes, and then keep it at 120℃ for 1 hour for stabilization and aging treatment. Step 5: Straighten, inspect, and store the heat-treated seamless aluminum tubes.

[0016] Example 5 A method for preparing 5B06 seamless aluminum tubing with scandium intergranular etching for surface ships. Step 1: Smelting and refining: Prepare all raw materials according to the specified amount. Heat the aluminum material and Mg, Si, and Mn to 750℃ and hold for 10 minutes. Then add Zr, Sc, and Ni and raise the temperature to 1000℃ and hold for 8 minutes. Refine in argon gas at 1100℃ for 10 minutes with a refining agent consisting of nano-silica, silane, dopamine, and magnesium chloride in a mass ratio of 2:0.3:2:1, which accounts for 0.1% of the molten liquid. Then refine in argon gas at 750℃ for 7 minutes. After vacuum circulation degassing, let stand and hold for 8 minutes. Step 2: Casting: Pour the mixture into ingots at a temperature of 700℃; Step 3: Hot extrusion and cold rolling: The aluminum alloy round casting rod is preheated to 550℃ and extruded into a seamless tube in an extruder. Then, it is quenched in quenching oil at 350℃ at a quenching rate of 20℃ / min and held for 3min. Then, it is water-cooled to 200℃ at a cooling rate of 15℃ / s. Subsequently, it is cooled to 90℃ under vacuum conditions for graded quenching and surface cleaning. The aluminum tube is then slowly cooled to 600℃ and cold-rolled with a deformation rate of 5%. It is then homogenized and annealed in a homogenizing furnace at 500℃ for 0.9h at a homogenization rate of 70℃ / h. The furnace atmosphere is hydrogen. Step 4: Heat treatment: Heat the pipe to 900℃, then keep it at 260℃ for 100 minutes, and then keep it at 110℃ for 1 hour for stabilization and aging treatment. Step 5: Straighten, inspect, and store the heat-treated seamless aluminum tubes.

[0017] Example 6 A method for preparing 5B06 seamless aluminum tubing with scandium intergranular etching for surface ships. Step 1: Smelting and refining: Prepare all raw materials according to the specified amount. Heat the aluminum material and Mg, Si, and Mn to 800℃ and hold for 10 minutes. Then add Zr, Sc, and Ni and raise the temperature to 1100℃ and hold for 5 minutes. Refine in argon gas at 1000℃ for 12 minutes with a refining agent consisting of nano-silica, silane, dopamine, and magnesium chloride in a mass ratio of 1.5:0.2:1:2, which accounts for 0.2% of the molten liquid. Then refine in argon gas at 700℃ for 8 minutes. After vacuum circulation degassing, let stand and hold for 4 minutes. Step 2: Casting: Pour the mixture into ingots at a temperature of 800℃; Step 3: Hot extrusion and cold rolling: The aluminum alloy round casting rod is preheated to 500℃ and extruded into a seamless tube in an extruder. Then, it is quenched in quenching oil at 400℃ at a quenching rate of 20℃ / min and held for 4min. Then, it is water-cooled to 200℃ at a cooling rate of 20℃ / s. Subsequently, it is cooled to 80℃ under vacuum conditions for graded quenching and surface cleaning. The aluminum tube is then slowly cooled to 600℃ and cold-rolled with a deformation rate of 10%. It is then homogenized and annealed in a homogenizing furnace at 400℃ for 1.0h at a homogenization rate of 60℃ / h. The furnace atmosphere is hydrogen. Step 4: Heat treatment: Heat the pipe to 1000℃, then hold it at 260℃ for 100 minutes, and then hold it at 100℃ for 2 hours for stabilization and aging treatment. Step 5: Straighten, inspect, and store the heat-treated seamless aluminum tubes.

[0018] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in the preparation process of Comparative Example 1, the melting in step 1 involves heating all raw materials to a temperature of 750°C and holding them at that temperature for 15 minutes, while other steps remain unchanged.

[0019] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in the preparation process of Comparative Example 2, argon gas containing refining agent is not used for refining in step 1; only argon gas refining is performed to remove impurities, while the rest remains unchanged.

[0020] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in the preparation process of Comparative Example 3, the cold rolling deformation rate in step 3 is 40%, the annealing rate is 10℃ / min, the annealing time is 7min, and other processes remain unchanged.

[0021] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that step 3 of the preparation process of Comparative Example 4 does not involve graded quenching, while the rest remains unchanged.

[0022] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the aluminum tube alloy material of Comparative Example 5 does not contain nickel, but is supplemented with aluminum, while other aspects remain unchanged.

[0023] The alloy composition addition ratios of aluminum tubes in Examples 1-6 and the comparative examples are shown in Table 1.

[0024] Table 1 Alloy Composition of Aluminum Tubes

[0025] As shown in Table 1, the aluminum tubes prepared by this invention have low impurity content, and the aluminum tubes are micro-alloyed by adding transition metals and nickel.

[0026] The tensile properties of the pipes are tested according to GB / T 228.1-2021, and the hardness of the pipes is tested using the Brinell / Rockwell hardness method according to ASTM E18-22. (Refer to GB / T...) The intergranular corrosion resistance of the tubing was tested using method 7998-2005. The aluminum tubing prepared in the examples and comparative examples was immersed in a hydrochloric acid solution with a concentration of 20 g / L for 72 h. The test results are shown in Table 2.

[0027] Table 2 Performance of 5B06 Seamless Aluminum Tubes

[0028] As can be seen from the data in Table 1, the seamless aluminum tube prepared by the present invention has good mechanical properties, such as good yield strength, tensile strength, and elongation, and has high resistance to intergranular corrosion, making it suitable for corrosive environments such as the ocean. As can be seen from Comparative Example 1, the present invention adds aluminum tube raw materials in batches and performs smelting at medium and high temperatures first and then at higher temperatures, which helps to suppress the precipitation of the second phase. The subsequent increase in temperature is conducive to the solid solution diffusion of nickel, zirconium and scandium, refines the grains, and improves the corrosion resistance and mechanical properties of seamless aluminum tubes. As can be seen from Comparative Example 2, the present invention uses argon gas containing refining agent and argon gas to remove impurities in the aluminum tube refining process, which can effectively reduce the impurity content of the aluminum tube, reduce the harm of other impurity grains to the tube, improve the fluidity of the raw materials, maintain the mechanical properties of the matrix, and improve the resistance to intergranular corrosion. As can be seen from Comparative Example 3, the present invention uses slow cooling and low deformation cold rolling followed by slow annealing. Compared with rapid annealing and relatively high deformation rate, it can control the lattice orientation while reducing the internal stress of grain boundaries, reducing grain boundary cracks, and improving the performance of aluminum tubes. As can be seen from Comparative Example 4, the staged quenching of aluminum tubes after hot extrusion in the later stage of the preparation process of the present invention can promote carbide precipitation, reduce corrosion channels, promote solid solution, improve grain boundary properties, and increase corrosion resistance. As can be seen from Comparative Example 5, the addition of trace amounts of nickel to the alloy material of this application can promote the formation of a corrosion-resistant phase in the transition metal and facilitate the cold and hot working of the material, thereby improving the intergranular corrosion resistance and other properties of the aluminum tube.

Claims

1. A method for producing a 5B06 seamless aluminum pipe material for a surface ship, which is resistant to intergranular corrosion, characterized by comprising the steps of: It comprises the following steps: ​ Step 1: smelting and refining: all raw materials are prepared according to the amount, aluminum materials and Mg, Si and Mn are heated to a temperature of 700-800℃ and kept for 10-20min, then Zr, Sc and Ni are added to increase the temperature to 1000-1100℃ and kept for 5-10min, then refined and placed; Step 2: casting: poured into ingots at a temperature of 700-800℃; Step 3: hot extrusion and cold rolling: the aluminum alloy round casting bar is preheated to 500-550℃, extruded into seamless pipes in an extruder, then washed after graded quenching, then cold rolled, and then uniformly annealed in a homogenizing furnace; Step 4: heat treatment: the pipe is heated to 800-1000℃, and then subjected to stable aging treatment; Step 5: the heat-treated seamless aluminum pipe is straightened, inspected and stored.

2. The method according to claim 1, wherein the method is characterized by, The refining in step 1 is carried out in argon containing a refining agent at a temperature of 1000-1100℃ for 8-12min, then refined in argon at a temperature of 700-800℃ for 6-8min, and then vacuum circulation degassing.

3. The method according to claim 1, wherein the method is characterized by the steps of: The amount of the refining agent is 0.1-0.2% of the molten liquid, which is composed of nano-silicon dioxide, silane, dopamine and magnesium chloride with a mass ratio of 0.5-2.5:0.1-0.4:1-3:1-3.

4. The method of claim 1, wherein the method is characterized by the steps of: The holding time of the standing in step 1 is 4-10min.

5. The method for preparing a seamless 5B06 aluminum tube for surface ships resistant to intergranular corrosion according to claim 1, characterized in that, The cold rolling in step 3 is slow cooling to a temperature of 550-600℃, and the deformation rate of cold rolling is 5-10%.

6. The method of claim 1, wherein the method is characterized by the steps of: The homogenization annealing in step 3 is carried out at a temperature of 400-500℃ for 0.8-1.0h, the annealing rate is 60-100℃ / h, and the heating furnace atmosphere is hydrogen atmosphere.

7. The method for preparing a seamless 5B06 aluminum tube for surface ships resistant to intergranular corrosion according to claim 1, characterized in that, The graded quenching in step 3 is carried out in quenching oil at a temperature of 300-400℃, the quenching speed is 20-30℃ / min, the holding time is 2-4min, then water-cooled to 200-300℃, the cooling rate is 10-20℃ / s, and then cooled to 80-120℃ under vacuum condition.

8. The method for preparing a seamless 5B06 aluminum tube for surface ships resistant to intergranular corrosion according to claim 1, characterized in that, The stable aging treatment in step 4 is to keep the pipe at a temperature of 260-280℃ for 80-100min, and then keep it at 100-120℃ for 1-2h.

9. The 5B06 seamless aluminum pipe material for a surface ship according to any one of claims 1 to 8, characterized by, It comprises the following components: Mg 1.0-1.5%, Si 0.4-0.8%, Mn 0.8-1.2%, Zr 0.1-0.25%, Sc 0.1-0.25%, Ni 0.1-0.2%, impurity content 0-0.3%, and the rest is Al.

10. The 5B06 seamless aluminum pipe for water surface vessels according to claim 9, wherein It comprises the following components: Mg 1.1-1.4%, Si 0.5-0.7%, Zr 0.15-0.2%, Sc 0.15-0.2%, Ni 0.12-0.18%, impurity content 0-0.3%, and the rest is Al.

Images