A kind of aluminum alloy seamless pipe manufacturing process for compressed hydrogen gas cylinders for 52Mpa long tube trailers

Abstract

The present invention provides a manufacturing process of aluminum alloy seamless tubes for compressed hydrogen gas cylinders for 52Mpa long-tube trailers, which relates to the technical field of large-caliber aluminum alloy seamless tubes, including three steps of material selection, extrusion and cold drawing, and is characterized in that: the material selection specification is 371×17.5mm inner diameter hot-extruded finished aluminum tube; the extrusion process includes raw material inspection, flaw detection, lubricant application, drying, extrusion by extruder, semi-finished product inspection and annealing; the cold drawing process includes lubricant application, drying, cold drawing by cold drawing machine, cold drawing inspection, flaw detection, sawing head and tail, tube mouth chamfering, inner surface grinding, outer surface polishing, finished product inspection and spraying marking. The hot-extruded finished aluminum tube is reprocessed through extrusion and cold drawing processes, and the geometric dimensions of the aluminum tube are changed through plastic deformation to achieve the purpose of expanding the diameter of the aluminum tube and reducing the wall thickness of the aluminum tube.

Description

Technical Field

[0001] The invention relates to the technical field of large-diameter aluminum alloy seamless pipes, and in particular to a manufacturing process of aluminum alloy seamless pipes for compressed hydrogen cylinders for 52Mpa long-tube trailers. Background Art

[0002] With the promotion and application of clean energy, my country's compressed hydrogen cylinders are gradually developing towards large-volume cylinders for heavy-duty vehicles, storage and transportation cylinders for long-tube trailers, and cylinders for hydrogen refueling stations. The traditional Type I and Type II steel cylinder liners are no longer suitable for current development needs. Their shortcomings are mainly reflected in two aspects. On the one hand, the possibility of hydrogen embrittlement of steel liners is relatively higher, and on the other hand, the bulk density of steel liners is relatively low. The 52Mpa long-tube trailer compressed hydrogen cylinder will enable the single-vehicle hydrogen transport capacity to exceed 1 ton, which is about 80% higher than the single-vehicle hydrogen transport capacity of Type I cylinders and about 50% higher than the single-vehicle hydrogen transport capacity of Type II cylinders, greatly reducing transportation costs, so that low-cost green hydrogen produced by photovoltaic and wind power generation over long distances can be smoothly transported to different usage scenarios, giving full play to the price advantage over oil, electricity and other energy sources, and completely solving the problem of curbing the development of hydrogen due to high hydrogen transportation costs, opening up the situation of comprehensive application of hydrogen. At the same time, the 52Mpa long-tube trailer compressed hydrogen cylinder can be directly filled with the 35Mpa vehicle compressed hydrogen cylinder, which reduces the investment in hydrogen refueling stations and completely solves the livelihood problem of difficult refueling. Therefore, the manufacturing process control of the aluminum alloy seamless pipe for the 52Mpa long-tube trailer compressed hydrogen cylinder used in the manufacture of long-tube trailers is particularly important.

[0003] The seamless aluminum tube is a large-diameter, thin-walled, long aluminum tube. Due to the limitations of the hot extrusion production process of the raw aluminum tube, the straightness and ovality of the large-diameter, thin-walled, long aluminum tube cannot be guaranteed, making it difficult to process. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a manufacturing process for aluminum alloy seamless tubes for compressed hydrogen cylinders for 52Mpa long-tube trailers, which solves the problem that the hot extrusion production process of raw aluminum tubes is limited and the straightness and ovality of large-diameter thin-walled long aluminum tubes cannot be guaranteed.

[0005] (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: A manufacturing process of aluminum alloy seamless tubes for compressed hydrogen cylinders for 52Mpa long-tube trailers, including three steps of material selection, extrusion and cold drawing. The material is a hot-extruded finished aluminum tube with an inner diameter of 371×17.5mm; The extrusion process includes raw material inspection, flaw detection, lubricant application, drying, extrusion by extruder, semi-finished product inspection and annealing; The cold drawing process includes applying lubricant, drying, cold drawing by cold drawing machine, cold drawing inspection, flaw detection, sawing head and tail, pipe mouth chamfering, inner surface grinding, outer surface polishing, finished product inspection and spray marking.

[0006] Preferably, the specification of the aluminum tube after extrusion is an inner diameter of 485×16 mm, and the specification of the aluminum tube after cold drawing is an outer diameter of 509×13 mm.

[0007] Preferably, the raw material inspection items in the extrusion process include but are not limited to the inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the raw aluminum tube; the semi-finished product inspection items in the extrusion process include but are not limited to wall thickness, surface quality, ovality and straightness; the cold drawing inspection items in the cold drawing process include but are not limited to wall thickness, surface quality, ovality and straightness; the finished product inspection items in the cold drawing process include but are not limited to inner and outer surface quality, weight, length, wall thickness, ovality and straightness.

[0008] Preferably, ultrasonic flaw detection is used in both the extrusion process and the cold drawing process.

[0009] Preferably, the configuration requirement of the lubricant applied in the extrusion process and the cold drawing process is that the mass ratio of water: paraffin: soap powder is 10:1-3:3-5.

[0010] Preferably, the drying temperature in the extrusion process and the cold drawing process is set to 80° C., and the drying time is set to 2 hours.

[0011] Preferably, the extrusion speed of the extruder is set to 15-17 cm / min, and the die diameter of the extruder is set to 485 mm.

[0012] Preferably, in the extrusion process, the annealing temperature is set to 420±5° C., the holding time is set to 2 hours, and the HB hardness after annealing is ≤40.

[0013] Preferably, the process parameters of the cold drawing machine are set to a cold drawing speed of 23 cm / min and a set pressure of 3.5 MPa. The inner die diameter of the cold drawing machine is 483 mm, and the outer die diameter is 511 mm.

[0014] Preferably, the sawing inclination of the sawing head and tail in the cold drawing process is ≤5mm, the pipe mouth chamfer is polished sequentially with a 60-mesh emery wheel and a polishing wheel to ensure that the pipe mouth is free of burrs, the inner surface is ground twice with a 60-mesh flap wheel and twice with a 320-mesh flap wheel, and the inner surface roughness after grinding does not exceed Ra2.0, the outer surface polishing requires manual inspection of surface quality and manual processing of defects, and the identification content of the spray mark includes product name, agreement number, brand, furnace number / batch number, and specifications.

[0015] Working principle: This seamless aluminum tube is a large-diameter, thin-walled, long aluminum tube. Due to the limitations of the hot extrusion production process of the raw aluminum tube, the straightness and ovality of the large-diameter, thin-walled, long aluminum tube cannot be guaranteed. Therefore, the hot-extruded finished aluminum tube is reprocessed through extrusion and cold drawing processes. After plastic deformation, the geometric dimensions of the aluminum tube are changed to achieve the purpose of expanding the diameter of the aluminum tube and reducing the wall thickness of the aluminum tube.

[0016] (III) Beneficial effects The present invention provides a manufacturing process of aluminum alloy seamless tube for compressed hydrogen cylinders for 52Mpa long tube trailers. It has the following beneficial effects: The aluminum alloy seamless tubes produced by this process have high material utilization rate, significantly improved production efficiency, and improved material organization and mechanical properties. After cold drawing, the material organization is denser, the diameter-to-wall ratio is increased, the wall thickness is more uniform, and the straightness and ovality of the 6000mm long tube can be guaranteed, which provides a safer guarantee for the manufacture of compressed hydrogen cylinders for 52Mpa long tube trailers and significantly improves the bulk density ratio of compressed hydrogen cylinders for 52Mpa long tube trailers. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example: The embodiment of the present invention provides a manufacturing process of an aluminum alloy seamless tube for a compressed hydrogen cylinder for a 52Mpa long tube trailer, comprising: selecting a hot-extruded finished aluminum tube with an inner diameter of 371×17.5mm as a raw aluminum tube, extruding it, and then cold drawing it into a finished product, The extrusion process flow is as follows: a hot-extruded finished aluminum tube with an inner diameter of 371×17.5 mm is used as a raw aluminum tube and an inner diameter of 485×16 mm is used as a cold-drawn raw aluminum tube.

[0019] 1) Inspect the inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the hot-extruded finished aluminum tube with an inner diameter of 371×17.5 mm as the raw aluminum tube; 2) Carry out ultrasonic flaw detection on each piece according to the standard; 3) Apply lubricant. The lubricant configuration requirements are: water: paraffin: soap powder = 10:1~3:3~5; the ratio unit is kg 4) Drying: 80℃, 2 hours to solidify the lubricant on the inner surface; 5) Adjust the process parameters of the extruder: extrusion speed 15-17cm / min; 6) Select the mold: diameter 485mm, clean the mold surface; 7) Extrusion; 8) Inspection of wall thickness, surface quality, ovality and straightness of semi-finished products; 9) Annealing: Annealing temperature 420±5℃, holding time 2 hours, HB hardness after annealing ≤40; The cold drawing process flow: 1) Apply lubricant. The lubricant configuration requirements are: water: paraffin: soap powder = 10:1~3:3~5; 2) Drying: 80°C, 2 hours to solidify the surface lubricant; 3) Adjust the process parameters of the cold drawing machine: cold drawing speed: 23cm / min; set pressure: 3.5Mpa; 4) Select the mold: inner mold diameter 483mm, outer mold diameter 511mm, and clean the mold surface; 5) cold drawing; 6) After cold drawing, inspect wall thickness, surface quality, ovality and straightness; 7) Carry out ultrasonic flaw detection one by one according to the standard; 8) Sawing head and tail, sawing slope ≤ 5mm; 9) Chamfer the pipe mouth and use a 60-grit sandpaper wheel and a polishing wheel to grind in sequence to ensure that there are no burrs on the pipe mouth.

[0020] 10) Grinding of inner surface: use 60 mesh flap wheel for two times and 320 mesh flap wheel for two times. The inner surface roughness after grinding shall not exceed Ra2.0; 11) External surface polishing, surface quality inspection and defects treatment are required manually in the middle; 12) Final product inspection: internal and external surface quality, weight, length, wall thickness, ovality and straightness; 13) Spraying mark, the mark content includes product name, agreement number, brand, furnace number / batch number, and specifications.

[0021] The size control range of aluminum alloy seamless pipe with outer diameter of 509×13×6000mm is: Outer diameter (0~﹢5mm): 509~514mm; Wall thickness (0~﹢1.5mm): 13~14.5mm; Multiple length: 6000mm; Length: 6000~6020mm; Internal and external surfaces: Both ends should be neat and burr-free, and the end sawing slope should be ≤5mm; Appearance: The inner and outer surfaces of the tube should be smooth, without any cracks, corrosion, inclusions, peeling, bubbles, abrasions, bruises, scratches, straight lines, pits and other defects. If there are any of the above defects, they should be ground to eliminate them. The grinding lines should be consistent (circumferential), and the roughness after grinding should not exceed Ra2.0; Printing identification: product name, agreement number, alloy grade, furnace number / batch number, specifications; According to the above process, the physical and chemical tests of aluminum alloy seamless pipe (material 6061) are shown in the following table: (Table 1) Chemical composition, analysis method is in accordance with GB / T20975: meet the requirements of the following table (wt)% It should meet the following requirements: Liquid hydrogen measurement ≤ 0.15ml / 100gAl.

[0022] The mechanical properties are shown in the following table. The room temperature tensile test method is carried out in accordance with the provisions of GB / T228: (Table 2) Mechanical properties The macrostructure is shown in the following table. The inspection method is in accordance with the provisions of GB / T 3246.2: (Table 3) Low-magnification tissue Microstructure: It should meet the requirements of GB / T4437.1. Overburned structure is not allowed. The inspection method shall be carried out in accordance with the provisions of GB / T3246.1.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process of aluminum alloy seamless tube for compressed hydrogen cylinders for 52Mpa long-tube trailers, comprising three steps of material selection, extrusion and cold drawing, characterized in that: The material is a hot-extruded finished aluminum tube with an inner diameter of 371×17.5mm; The extrusion process includes raw material inspection, flaw detection, lubricant application, drying, extrusion by extruder, semi-finished product inspection and annealing; The cold drawing process includes applying lubricant, drying, cold drawing by cold drawing machine, cold drawing inspection, flaw detection, sawing head and tail, pipe mouth chamfering, inner surface grinding, outer surface polishing, finished product inspection and spray marking.

2. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized by: The specification of the aluminum tube after extrusion is an inner diameter of 485×16 mm, and the specification of the aluminum tube after cold drawing is an outer diameter of 509×13 mm.

3. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized in that: The raw material inspection items in the extrusion process include but are not limited to the inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the raw aluminum tube; the semi-finished product inspection items in the extrusion process include but are not limited to wall thickness, surface quality, ovality and straightness; the cold drawing inspection items in the cold drawing process include but are not limited to wall thickness, surface quality, ovality and straightness; the finished product inspection items in the cold drawing process include but are not limited to inner and outer surface quality, weight, length, wall thickness, ovality and straightness.

4. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized in that: Ultrasonic testing is used in the flaw detection process in both the extrusion process and the cold drawing process.

5. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized in that: The configuration requirement of the lubricant applied in the extrusion process and the cold drawing process is that the mass ratio of water: paraffin: soap powder is 10:1-3:3-5.

6. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized in that: The drying temperature in the extrusion process and the cold drawing process is set to 80° C. and the drying time is set to 2 hours.

7. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized by: The extrusion speed of the extruder is set to 15-17 cm / min, and the die diameter of the extruder is set to 485 mm.

8. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1 is characterized by: In the extrusion process, the annealing temperature is set to 420±5° C., the holding time is set to 2 hours, and the HB hardness after annealing is ≤40.

9. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for 52Mpa long tube trailer according to claim 1, characterized in that: The process parameters of the cold drawing machine are set to a cold drawing speed of 23 cm / min and a set pressure of 3.5 MPa. The inner die diameter of the cold drawing machine is 483 mm and the outer die diameter is 511 mm.

10. The manufacturing process of the aluminum alloy seamless tube for the compressed hydrogen cylinder for the 52Mpa long tube trailer according to claim 1, characterized in that: The sawing inclination of the sawing head and tail in the cold drawing process is ≤5mm, the pipe mouth chamfer is polished sequentially with a 60-mesh emery wheel and a polishing wheel, the inner surface is ground twice with a 60-mesh flap wheel and twice with a 320-mesh flap wheel, and the inner surface roughness after grinding does not exceed Ra2.

0. The outer surface polishing requires manual inspection of surface quality and manual processing of defects. The spray mark includes product name, agreement number, brand, furnace number / batch number, and specifications.

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