Manufacturing process and application of aluminum alloy seamless tube for 35Mpa compressed hydrogen gas cylinder for vehicle

Abstract

The invention provides a manufacturing process of an aluminum alloy seamless tube for a 35Mpa compressed hydrogen gas cylinder for a vehicle, and relates to the field of manufacturing and application of large-diameter aluminum alloy seamless tubes. The manufacturing process of the aluminum alloy seamless tube for the 35Mpa compressed hydrogen gas cylinder for the vehicle comprises the following specific steps: step S1, a primary extrusion process flow: taking an inner 371 * 11.5 mm hot extrusion finished product aluminum tube as a raw material aluminum tube, and performing primary extrusion to an inner 457 * 11.2 mm to serve as a raw material aluminum tube for secondary extrusion; s11, the inner surface, the outer surface, the outer diameter, the wall thickness, the straightness and the ovality of the hot extrusion finished aluminum pipe with the specification of 371 * 11.5 mm as a raw material aluminum pipe are inspected; and S12, ultrasonic flaw detection is carried out one by one according to the standard. An existing forming process for producing an aluminum liner needs about 240-280 min, the aluminum alloy seamless pipe produced through the process can omit the procedures of cold spinning, saw cutting, inner and outer surface coping and ultrasonic cleaning in the forming process of the aluminum liner, about 180-220 min is saved (about 80% of time cost is saved), and the production efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of large-diameter aluminum alloy seamless pipe manufacturing, and specifically to a manufacturing process and application of an aluminum alloy seamless pipe for a 35Mpa vehicle compressed hydrogen cylinder. Background Art

[0003] The production process of 35Mpa vehicle compressed hydrogen cylinders is complicated, especially the high cost of cold spinning, sawing, inner and outer surface grinding, and ultrasonic cleaning in the aluminum liner forming process, resulting in low production efficiency of 35Mpa vehicle compressed hydrogen cylinders. This product is an upgraded product of the 15.5 mm wall thickness product. Compared with the previous generation of products, the material utilization rate can reach 100%. On the basis of the original product, 35Mpa vehicle compressed hydrogen cylinder manufacturers no longer need cold spinning, sawing, inner and outer surface grinding, ultrasonic cleaning and other processes in the production of aluminum liner, and can directly enter the hot spinning closing process, which greatly reduces the manufacturing costs of energy, consumables, labor, equipment depreciation, etc. in the above processes during the production process. At the same time, it greatly reduces the environmental protection costs such as hydraulic oil, cleaning agent, and collection of grinding dust in the above processes, avoiding the quality risks of the above processes in the production process. The existing aluminum liner forming process requires about 240 to 280 minutes to produce an aluminum liner through the aluminum alloy seamless tube cold spinning, sawing, inner and outer surface grinding, ultrasonic cleaning, and hot spinning. The aluminum alloy seamless tube produced by this process can be used in the aluminum liner forming process to save the cold spinning, sawing, inner and outer surface grinding, and ultrasonic cleaning processes, saving about 180 to 220 minutes (saving about 80% of the time cost), and the production efficiency is greatly improved. In addition, while improving fatigue resistance, the use of carbon fiber is reduced, achieving the goal of continuously reducing the manufacturing cost of 35Mpa vehicle compressed hydrogen cylinders. 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 and application of aluminum alloy seamless pipes for 35Mpa vehicle compressed hydrogen cylinders, which solves the manufacturing costs such as energy, consumables, labor, and equipment depreciation in the production process, while greatly reducing environmental protection costs such as hydraulic oil, cleaning agents, and collection of grinding dust, avoiding quality risks in the production process.

[0005] (II) Technical solution To achieve the above objectives, the present invention is implemented by the following technical solutions: a manufacturing process of aluminum alloy seamless pipes for 35Mpa vehicle compressed hydrogen cylinders, through which specifications Ø 内 549×10mm 35Mpa vehicle compressed hydrogen cylinder with 10mm wall thickness aluminum alloy seamless pipe, select specification Ø 内The 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, and is extruded into the finished product through three steps, including the following specific steps: Step S1: Extrusion process: Ø 内 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, and extruded to Ø 内 457×11.2mm is used as the raw material aluminum tube for the second extrusion process. The specific steps include: Step S11, check the specifications 内 The inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the 371×11.5mm hot extruded finished aluminum tube as the raw aluminum tube; Step S12, performing ultrasonic flaw detection on each piece according to the standard; Step S13, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S14, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S15, adjusting the process parameters of the extruder: extrusion speed 15-17 cm / min; Step S16, select the mold: Ø457mm, and clean the mold surface; Step S17, performing the first extrusion; Step S18, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S19, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing ≤40.

[0006] Preferably, the step S2 comprises a second extrusion process flow: 内 457×11.2mm one-pass extruded aluminum tube is used as the raw aluminum tube, and the second pass extrusion to Ø 内 520×10.5mm is used as the raw material aluminum tube for extrusion three times. The specific steps include: Step S21, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S22, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S23, adjusting the process parameters of the extruder: extrusion speed 12-14 cm / min; Step S24, select a mold: Ø520mm, and clean the mold surface; Step S25, performing a second extrusion; Step S26, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S27, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing ≤40.

[0007] Preferably, the step S3 comprises three extrusion process steps: 内 520×10.5mm two-pass extruded aluminum tube is used as the raw aluminum tube, and three-pass extrusion to Ø 内 549×10mm, Step S31, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S32, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S33, adjusting the process parameters of the extruder: extrusion speed 10-12 cm / min; Step S34, select the mold: Ø549mm, and clean the mold surface; Step S35, performing the third extrusion; Step S36, inspecting the wall thickness, surface quality, ovality and straightness after three extrusions; Step S37, perform ultrasonic flaw detection on each piece according to the standard; Step S38: Sawing, with a sawing slope of ≤5 mm.

[0008] Preferably, the three-step extrusion process in step S3 also includes the following specific steps: Step S39, chamfer the pipe mouth, and grind it in sequence using a 60-mesh emery wheel and a polishing wheel to ensure that the pipe mouth has no burrs; Step S310, annealing: annealing temperature 350±5°C, holding time 2.5h, HB hardness after annealing ≤50; Step S311, inner surface grinding: use a 60-mesh flap wheel to grind twice, and a 320-mesh flap wheel to grind twice, and the inner surface roughness after grinding does not exceed Ra2.0; Step S312: polishing the outer surface, during which the surface quality needs to be manually inspected and defects are manually processed; Step S313: inspect the internal and external surface quality, weight, length, wall thickness, ovality and straightness of the final product; Step S314, spraying a label, the label content includes product name, agreement number, brand, furnace number / batch number, and specifications.

[0009] Preferably, an aluminum alloy seamless tube for a 35Mpa vehicle compressed hydrogen cylinder is obtained by the above-mentioned manufacturing method.

[0010] Preferably, the inner diameter range of the aluminum alloy seamless tube is 549.5-552mm, the wall thickness range is (-1.0mm~﹢1.0mm) 9~11mm, the multiple length is 2200mm, the length is 2200~2220mm, the shortest part shall not be shorter than the multiple length, the single tube weight is 105~109Kg, and the sawing slope of the inner and outer surface ends is ≤5mm.

[0011] Preferably, a 35Mpa vehicle compressed hydrogen cylinder is obtained by closing the end and the bottom of the aluminum alloy seamless pipe.

[0012] (III) Beneficial effects The present invention provides a manufacturing process and application of aluminum alloy seamless pipe for 35Mpa vehicle compressed hydrogen cylinder. It has the following beneficial effects: The product in the present invention is an upgraded product of the product with a wall thickness of 15.5mm. Compared with the traditional product, the material utilization rate can reach 100%. On the basis of the original product, the 35Mpa vehicle compressed hydrogen cylinder manufacturer no longer needs cold spinning, sawing, inner and outer surface grinding, and ultrasonic cleaning processes in the production process of aluminum liner, and directly enters the hot spinning closing process, which greatly reduces the manufacturing costs of energy, consumables, labor, equipment depreciation, etc. in the above process in the production process, and at the same time greatly reduces the environmental protection costs such as hydraulic oil, cleaning agent, and collection of grinding dust in the above process, avoiding the quality risks of the above process in the production process. The existing aluminum liner forming process produces an aluminum liner through the aluminum alloy seamless tube cold spinning, sawing, inner and outer surface grinding, ultrasonic cleaning, and hot spinning closing forming process, which takes about 240 to 280 minutes. The aluminum alloy seamless tube produced by this process can be used in the aluminum liner forming process to save cold spinning, sawing, inner and outer surface grinding, and ultrasonic cleaning processes, saving about 180 to 220 minutes (saving about 80% of time cost), and the production efficiency is greatly improved. In addition, while improving fatigue resistance, the amount of carbon fiber used is reduced, achieving the goal of continuously reducing the manufacturing cost of 35Mpa automotive compressed hydrogen cylinders. DETAILED DESCRIPTION

[0013] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0014] Embodiment 1: The embodiment of the present invention provides a manufacturing process of aluminum alloy seamless pipe for 35Mpa vehicle compressed hydrogen cylinder, and the technical solution of the present invention is used to manufacture aluminum alloy seamless pipes with material 6061 and specification Ø 内549×10mm 35Mpa vehicle compressed hydrogen cylinder wall thickness 10mm aluminum alloy seamless pipe, the process steps are: through this process can manufacture specifications Ø 内 549×10mm 35Mpa vehicle compressed hydrogen cylinder with 10mm wall thickness aluminum alloy seamless pipe, select specification Ø 内 The 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, and is extruded into the finished product through three steps, including the following specific steps: Step S1: Extrusion process: Ø 内 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, and extruded to Ø 内 457×11.2mm is used as the raw material aluminum tube for the second extrusion process; the specific steps include: Step S11, check the specifications 内 The inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the 371×11.5mm hot extruded finished aluminum tube as the raw aluminum tube; Step S12, performing ultrasonic flaw detection on each piece according to the standard; Step S13, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S14, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S15, adjusting the process parameters of the extruder: extrusion speed 15-17 cm / min; Step S16, select the mold: Ø457mm, and clean the mold surface; Step S17, performing the first extrusion; Step S18, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S19, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing ≤40.

[0015] A manufacturing process for aluminum alloy seamless pipes for 35Mpa vehicle compressed hydrogen cylinders is applied to the field of large-diameter aluminum alloy seamless pipe manufacturing.

[0016] Embodiment 2: This embodiment differs from Embodiment 1 in that: The second extrusion process of step S2 is as follows: 内 457×11.2mm one-pass extruded aluminum tube is used as the raw aluminum tube, and the second pass extrusion to Ø 内 520×10.5mm is used as the raw material aluminum tube for extrusion three times. The specific steps include: Step S21, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S22, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S23, adjusting the process parameters of the extruder: extrusion speed 12-14 cm / min; Step S24, select a mold: Ø520mm, and clean the mold surface; Step S25, performing a second extrusion; Step S26, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S27, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing 40.

[0017] Embodiment 3: This embodiment differs from Embodiment 1 and Embodiment 2 in that: The step S3 extrudes three process steps: 内 520×10.5mm two-pass extruded aluminum tube is used as the raw aluminum tube, and three-pass extrusion to Ø 内 549×10mm, the specific steps include: Step S31, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S32, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S33, adjusting the process parameters of the extruder: extrusion speed 10-12 cm / min; Step S34, select the mold: Ø549mm, and clean the mold surface; Step S35, performing the third extrusion; Step S36, inspecting the wall thickness, surface quality, ovality and straightness after three extrusions; Step S37, perform ultrasonic flaw detection on each piece according to the standard; Step S38: Sawing with a sawing slope of 5 mm.

[0018] Step S39, chamfer the pipe mouth, and grind it in sequence using a 60-mesh emery wheel and a polishing wheel to ensure that the pipe mouth has no burrs; Step S310, annealing: annealing temperature 350±5°C, holding time 2.5h, HB hardness after annealing 50; Step S311, inner surface grinding: use a 60-mesh flap wheel to grind twice, and a 320-mesh flap wheel to grind twice, and the inner surface roughness after grinding does not exceed Ra2.0; Step S312: polishing the outer surface, during which the surface quality needs to be manually inspected and defects are manually processed; Step S313: inspect the internal and external surface quality, weight, length, wall thickness, ovality and straightness of the final product; Step S314, spraying identification, the identification content includes product name, agreement number, brand, furnace number / batch number, and specifications.

[0019] The inner diameter range of aluminum alloy seamless pipe is 549.5-552mm, the wall thickness range is (-1.0mm~﹢1.0mm) 9~11mm, the multiple length is 2200mm, the length is 2200~2220mm, the shortest part shall not be shorter than the multiple length, the single weight is 105~109Kg, and the sawing slope of the inner and outer surface ends is ≤5mm.

[0020] A 35Mpa vehicle compressed hydrogen cylinder is obtained by closing the end and the bottom of the aluminum alloy seamless pipe.

[0021] Inner diameter range: 549.5-552mm; Wall thickness range: (-1.0mm~﹢1.0mm): 9~11mm; Multiple length: 2200mm; Length: 2200~2220mm; The shortest part shall not be shorter than the multiple length; Single weight: 105~109Kg; Ultrasonic inspection: Defect control complies with the requirements of Appendix C of GB / T24160-2022; 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, brand, furnace number / batch number, specifications.

[0022] 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)% Table 1 It should meet the following requirements: Liquid hydrogen measurement ≤ 0.15ml / 100gAl.

[0023] 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 Table 2 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 Table 3 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.

[0024] The above description is only an embodiment of the present invention and does not limit the protection scope of the present invention.

[0025] 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 process for manufacturing aluminum alloy seamless pipes for 35Mpa vehicle compressed hydrogen cylinders, which can be manufactured with specifications of Ø 内 549×10mm 35Mpa vehicle compressed hydrogen cylinder with 10mm wall thickness aluminum alloy seamless pipe, select specification Ø 内 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, which is extruded into the finished product through three steps. The characteristics are: The specific steps include: Step S1: Extrusion process: Ø 内 371×11.5mm hot extruded finished aluminum tube is used as the raw aluminum tube, and extruded to Ø 内 457×11.2mm is used as the raw material aluminum tube for the second extrusion process; Step S2: Extrusion Secondary Process Flow: From Ø 内 457×11.2mm one-pass extruded aluminum tube is used as the raw aluminum tube, and the second pass extrusion to Ø 内 520×10.5mm is used as the raw aluminum tube for extrusion three times; Step S3: Extrusion three-step process flow: from Ø 内 520×10.5mm two-pass extruded aluminum tube is used as the raw aluminum tube, and three-pass extrusion to Ø 内 549×10mm.

2. The manufacturing process of a 35Mpa aluminum alloy seamless pipe for a vehicle compressed hydrogen cylinder according to claim 1, characterized in that: The specific steps of step S1 include: Step S11, check the specifications 内 The inner and outer surfaces, outer diameter, wall thickness, straightness and ovality of the 371×11.5mm hot extruded finished aluminum tube as the raw aluminum tube; Step S12, performing ultrasonic flaw detection on each piece according to the standard; Step S13, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S14, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S15, adjusting the process parameters of the extruder: extrusion speed 15-17 cm / min; Step S16, select the mold: Ø457mm, and clean the mold surface; Step S17, performing the first extrusion; Step S18, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S19, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing ≤40.

3. The manufacturing process of a 35Mpa aluminum alloy seamless pipe for a vehicle compressed hydrogen cylinder according to claim 1, characterized in that: The specific steps of step S2 include: Step S21, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S22, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S23, adjusting the process parameters of the extruder: extrusion speed 12-14 cm / min; Step S24, select a mold: Ø520mm, and clean the mold surface; Step S25, performing a second extrusion; Step S26, inspect the wall thickness, surface quality, ovality and straightness of the semi-finished product; Step S27, annealing: annealing temperature 420±5°C, holding time 2h, HB hardness after annealing ≤40.

4. The manufacturing process of a 35Mpa aluminum alloy seamless pipe for a vehicle compressed hydrogen cylinder according to claim 1, characterized in that: The specific steps of step S3 include: Step S31, applying lubricant, the lubricant configuration requirement is: water: paraffin: soap powder = 10:1-3:3-5; Step S32, drying: 80°C, 2h, to solidify the inner surface lubricant; Step S33, adjusting the process parameters of the extruder: extrusion speed 10-12 cm / min; Step S34, select the mold: Ø549mm, and clean the mold surface; Step S35, performing the third extrusion; Step S36, inspecting the wall thickness, surface quality, ovality and straightness after three extrusions; Step S37, perform ultrasonic flaw detection on each piece according to the standard; Step S38: Sawing, with a sawing slope of ≤5 mm.

5. The manufacturing process of a 35Mpa aluminum alloy seamless pipe for a vehicle compressed hydrogen cylinder according to claim 4, characterized in that: The step S3 extrusion three-pass process flow also includes the following specific steps: Step S39, chamfer the pipe mouth, and grind it in sequence using a 60-mesh emery wheel and a polishing wheel to ensure that the pipe mouth has no burrs; Step S310, annealing: annealing temperature 350±5°C, holding time 2.5h, HB hardness after annealing ≤50; Step S311, inner surface grinding: use a 60-mesh flap wheel to grind twice, and a 320-mesh flap wheel to grind twice, and the inner surface roughness after grinding does not exceed Ra2.0; Step S312: polishing the outer surface, during which the surface quality needs to be manually inspected and defects are manually processed; Step S313: inspect the internal and external surface quality, weight, length, wall thickness, ovality and straightness of the final product; Step S314, spraying a label, the label content includes product name, agreement number, brand, furnace number / batch number, and specifications.

6. A 35Mpa aluminum alloy seamless tube for vehicle compressed hydrogen cylinders, characterized in that: Obtained by the production method according to any one of claims 1 to 5.

7. The aluminum alloy seamless pipe for 35Mpa vehicle compressed hydrogen cylinder according to claim 6, characterized in that: The inner diameter range of the aluminum alloy seamless tube is 549.5-552mm, the wall thickness range is (-1.0mm~﹢1.0mm) 9~11mm, the multiple length is 2200mm, the length is 2200~2220mm, the shortest part shall not be shorter than the multiple length, the single tube weight is 105~109Kg, and the sawing inclination of the inner and outer surface ends is ≤5mm.

8. A 35Mpa vehicle compressed hydrogen cylinder, characterized in that: The aluminum alloy seamless pipe according to claim 6 or 7 is obtained by closing the ends and the bottom.

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