CN103290281A - Manufacturing method of high-strength aluminum alloy pipe - Google Patents
Manufacturing method of high-strength aluminum alloy pipe Download PDFInfo
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- CN103290281A CN103290281A CN2013102712010A CN201310271201A CN103290281A CN 103290281 A CN103290281 A CN 103290281A CN 2013102712010 A CN2013102712010 A CN 2013102712010A CN 201310271201 A CN201310271201 A CN 201310271201A CN 103290281 A CN103290281 A CN 103290281A
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Abstract
The invention relates to a manufacturing method of a high-strength aluminum alloy pipe. A alloy comprises the following raw materials in percentage by weight: 5.1%-6.4% of Zn, 1.8%-2.1% of Mg, 1.7%-2.0% of Cu, 0.18%-0.24% of Zr and the balance of Al, wherein the sum of the components is 100%. According to the invention, the used powder is higher in purity and small in particle diameter, so that harmful impurities are prevented from being added as far as possible; and the tissue of the alloy is in a polyphase fine dispersed distribution state, so that the alloy has good integrated mechanical property, and the property of the alloy is enhanced.
Description
Technical field
The present invention relates to a kind of manufacture method of aldural tubing, particularly a kind of manufacture method of aluminium zinc-magnesium copper zirconium series high-strength aluminum alloy tubing.
Background technology
The energy, environmental protection, safety are the Three Difficult Issues that are related to human survival and development.But aluminium has, and density is little, specific tenacity and specific rigidity height, corrosion-resistant, attractive and durable, easy shaping surface treatment, recyclable regeneration, can save energy a series of premium propertiess such as energy storage, and applying aluminium is the important channel of alleviating above-mentioned Three Difficult Issues.Therefore, aluminium more and more is subjected to people's favor, and it is used and to have spread to national economy all departments and the people each side of living, has replaced iron and steel, copper material, timber and plastics in a lot of occasions, becomes a kind of important base mateiral of human society.
Aluminium is a kind of argenteous metal, and it is low to have density, has only 2.79/cm
3, the density that is about steel, copper or brass (is respectively 7.839/cm
3, 8.939/cm
3) 1/3.Characteristics such as electroconductibility and thermal conductivity are good, plasticity is high, corrosion resistance is good, the surface of aluminium has the reflectivity of height, radiating capacity, visible light, radiant heat and electric wave can both be reflected by aluminium effectively, and anodic oxidation and dark anodised surface can be reflexive, also can be absorbefacient, aluminium after the polishing has good reflectivity in very wide wavelength region, thereby has various decorative uses and have the purposes of reflection function.The chemical property of aluminium is active, easily is combined with oxygen in air, and the surface forms the fine and close firm aluminum oxide film of one deck, can protect inner layer metal no longer to continue oxidation, so fabulous stability is arranged in atmosphere.The standing stock of aluminium in the Nature are very abundant, and the content of aluminium in the earth's crust is 7.45%, is only second to oxygen and silicon, the reserves of China's bauxite are also at the forefront in the world, proven reserve have 6.3 hundred million tons, and it is a kind of metal with very strong reproducibility, and its " green life power " can be for continuing performance.In the modern life, aluminium and aluminium alloy have been widely used in the various industries.
Aluminium alloy has the following advantages:
(1) density is little: density is little to be highly profitable for the vehicles such as aerospace craft, boats and ships, vehicle and buildings lightweight, in communications and transportation, can significantly reduce oil consumption, simultaneously also can save porterage and process cost, reduce cost, in the application in fields such as industry, construction industry, civilian industry more and more widely.
(2) good anti-corrosion, weathering resistance: aluminium and aluminium alloy can form one deck in atmosphere hard and fine and close, oxide film with good corrosion energy, by surface treatments such as anodic oxidation, electrophoretic painting, powder sprayings, can further improve the erosion resistance of aluminium.
(3) good machinability and ornamental: aluminium alloy has good plasticity-, can process the product of all size, shape, can generate different properties by surface treatment, and the rete of different colours has good ornamental.
(4) good thermal conductivity: the thermal conductivity of aluminium alloy approximately is 50.60% of copper, and this is to making heat exchanger, vaporizer, heating electrical appliance, cooking utensils, and the cylinder cap of automobile and scatterer are highly beneficial.
(5) good forging property: aluminium alloy can forge into intensity height, shape and forging various in style, and it is non-constant width that their final parts forge the range of choice of standard (based on predetermined purposes).
(6) good weldability: aluminium alloy can connect with method miscellaneous, comprise melting welding, resistance welding, hard solder, soft soldering, bonding and the mechanical means such as riveted joint and bolt.
(7) high recovery: the characteristic of secondary aluminium alloy and primary aluminium alloy almost not, this point makes aluminium alloy become environmentalist's favorite.The feature of environmental protection is fairly good.
(8) aluminium alloy has high specific tenacity, specific rigidity, fracture toughness property and fatigue strength: replace ferrous materials can alleviate the weight of zero member greatly with it, increase stability of structure.As a kind of structural timber, at the liquid guided missile, launch vehicle is used widely in the aircraft, and is also very extensive in other sector application.
(9) special aluminum alloy has high resistivity: these alloys can be used in the electric motor as high torque (HT).
Aluminium alloy can be divided into wrought aluminium alloy and cast aluminium alloy by working method.
The sorting technique of wrought aluminium alloy is a lot, and at present, most countries classify by following three kinds of methods usually in the world.
(1) is divided into heat-treatable strengthened aluminum alloy and not heat-treatable strengthened aluminium alloy two big classes by structural diagram and thermal treatment characteristics.Heat-treatable strengthened type aluminium alloy can improve mechanical property by thermal treatment means such as quenching and timeliness.It can be divided into duralumin, wrought aluminium, ultralumin and particular aluminum alloy etc.; Aluminium alloy can adopt thermal treatment to obtain favorable mechanical performance, physicals and corrosion resistance.Heat-treatable strengthened aluminum alloy as: fine aluminium, Al-Mn, Al-Mg, Al-Si are alloy.Not heat-treatable strengthened type can not improve mechanical property by thermal treatment, can only realize strengthening by cold deformation, and it mainly comprises rafifinal, industrial rafifinal, commercial-purity aluminium and corrosion-resisting aluminium etc.Not heat-treatable strengthened aluminium alloy as: Al-Mg, Si, Al-Cu, Al-Zn-Mg are alloy.
(2) can be divided into by alloy property and purposes: commercial-purity aluminium, brilliant aluminium alloy, cut aluminum alloy, heat-resisting aluminium alloy, low strength aluminium alloy, middle strength aluminium alloy, aldural (duralumin), ultrahigh-strength aluminum alloy (ultralumin), reflectal and particular aluminum alloy etc.
(3) can be divided into by contained main alloy element composition in the alloy: commercial-purity aluminium, Al-Cu alloy, Al-Mn alloy, Al-Si alloy, Al-Mg alloy, Al-Mg-Si alloy, Al-Zn alloy, other mischmetal element of AL-.
The Al-Zn-Mg-Cu alloy belongs to ultra-high-strength aluminum alloy, is heat-treatable strengthened alloy, has higher specific tenacity, but because under the peak value timeliness state, stress corrosion resistant ability and fracture toughness property are all poor, have limited its widespread use.
Existing aluminium-alloy pipe is owing to the deficiency of intensity and production technique, and the fluctuation of the mechanical properties of tubular goods of production is big, and shaping such as follow-up crooked enlarging processing is very not smooth, occurs waste product often.Therefore, optimize the good alloy of alloying constituent and thermal treatment process acquisition over-all properties is the target of the common pursuit of vast investigation of materials work always.
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Summary of the invention
Purpose of the present invention is intended at the technical deficiency of existing high strength alumin ium alloy tubing and defective, provide that a kind of reasonable mixture ratio of components, production technique are simple, the preparation method of the aluminium zinc-magnesium copper zirconium series high-strength aluminum alloy tubing of the bulk strength that can effectively improve aluminium alloy and stability, the performance of aluminium alloy pipe approached or surpass existing casting or goods that forging method is produced.
The present invention solves its technical problem and adopts following technical scheme:
A kind of manufacture method of aldural tubing is characterized in that, comprises the steps:
1) according to following component configuration alloy raw material, Zn 5.1 ~ 6.4%, and Mg 1.8 ~ 2.1%, and Cu 1.7 ~ 2.0%, and Zr 0.18 ~ 0.24%, and surplus is Al, and each component sum is 100%; Wherein, Al, Zn, Mg, Cu, Zr are the pure element powder of purity more than 99.5%, and alloying ingredient is 10 μ m copper powders, 2 μ m aluminium powders, 20 μ m magnesium powder, 6 ~ 9 μ m zinc powders and 2 ~ 3 μ m zirconium powders,
2) with 150 rev/mins speed ball milling 24h, compound material body carries out cryogenic high pressure vacuum heating-press sintering, vacuum tightness≤0.01Pa to element powders in the vacuum heating-press sintering stove on light-duty ball mill, sintering temperature is 550 ℃, sintering time is 3h, and sintering pressure is 80MPa
3) sintered compact that adopts the cryogenic high pressure vacuum heating-press sintering is carried out high temperature solid solution thermal treatment, temperature is 620 ℃, vacuum tightness≤0.01Pa, and sintering time 12h,
4) sample behind the sintering is through hot extrusion, the money mold preheating temperature is 480 ℃ before the extruding, extrusion ratio is 4:1 ~ 15:1, extruding rate is 1.4m/min, and extrusion carries out one-level solid solution 2h at 470 ℃, is warming up to 485 ℃ of secondary solid solution 2h afterwards, quench in the room temperature water, carry out one-level timeliness 24h at 120 ℃ then, be warming up to 170 ℃ of secondary time effect 1h, be cooled to 120 ℃ of three grades of timeliness 24h.
The present invention compared with prior art has following major advantage: the present invention by a large amount of experimental selection rational proportion, especially raw material of the present invention all adopts the method for pure element powder to carry out batch mixing, pass through ball mill mixing, several element powders are fully mixed, then by a large amount of experiments, select suitable cryogenic high pressure vacuum heating-press sintering and high temperature solid solution heat treating method and parameter, make zinc, magnesium, copper, the solid solution in aluminum substrate of elements such as zirconium surpasses its theoretical solid solubility, and powdered reaction is fully carried out, to obtain the density height, porosity is few, the sintered state sample that intermetallic compound phase small and dispersed distributes, heat-treat again and obtain the timeliness precipitation strength phase that nano-scale distributes, finally make alloy organizing be in heterogeneous small and dispersed distribution, thereby make it have good comprehensive mechanical performance, simultaneously, owing to there is not Fe, the influence of impurity elements such as Si, its performance is further strengthened, the aluminium zinc-magnesium copper series high-strength aluminum alloy pipe that the intensity of the aluminium-alloy pipe that makes at last approaches or surpasses existing casting or forge.The powder purity that the present invention uses is higher, particle diameter is tiny, avoids the adding of detrimental impurity as far as possible, makes the performance of alloy obtain reinforcement to a certain extent.The present invention can produce accurate in size product, has characteristics such as simple to operate, that loss amount is few, controllability is good.
Embodiment
The invention will be further described below in conjunction with embodiment, but do not limit the present invention.
Embodiment 1
1) according to following component configuration alloy raw material, Zn 5.1%, and Mg 1.8%, and Cu 1.7%, and Zr 0.18%, and surplus is Al, and each component sum is 100%; Wherein, Al, Zn, Mg, Cu, Zr are the pure element powder of purity more than 99.5%, and alloying ingredient is 10 μ m copper powders, 2 μ m aluminium powders, 20 μ m magnesium powder, 6 ~ 9 μ m zinc powders and 2 ~ 3 μ m zirconium powders.
2) with 150 rev/mins speed ball milling 24h, compound material body carries out cryogenic high pressure vacuum heating-press sintering, vacuum tightness≤0.01Pa to element powders in the vacuum heating-press sintering stove on light-duty ball mill, sintering temperature is 550 ℃, sintering time is 3h, and sintering pressure is 80MPa
3) sintered compact that adopts the cryogenic high pressure vacuum heating-press sintering is carried out high temperature solid solution thermal treatment, temperature is 620 ℃, vacuum tightness≤0.01Pa, and sintering time 12h,
4) sample behind the sintering is through hot extrusion, the money mold preheating temperature is 480 ℃ before the extruding, extrusion ratio is 4:1, extruding rate is 1.4m/min, and extrusion carries out one-level solid solution 2h at 470 ℃, is warming up to 485 ℃ of secondary solid solution 2h afterwards, quench in the room temperature water, carry out one-level timeliness 24h at 120 ℃ then, be warming up to 170 ℃ of secondary time effect 1h, be cooled to 120 ℃ of three grades of timeliness 24h.
The void content of the aluminium alloy pipe that makes at last≤0.01%, density are 2.79g/cm
2, the maximum tensile strength 〉=475MPa, hardness value is 〉=181HV.
Embodiment 2
1) according to following component configuration alloy raw material, Zn 5.8%, and Mg 1.9%, and Cu 1.8%, and Zr 0.21%, and surplus is Al, and each component sum is 100%; Wherein, Al, Zn, Mg, Cu, Zr are the pure element powder of purity more than 99.5%, and alloying ingredient is 10 μ m copper powders, 2 μ m aluminium powders, 20 μ m magnesium powder, 6 ~ 9 μ m zinc powders and 2 ~ 3 μ m zirconium powders.
2) with 150 rev/mins speed ball milling 24h, compound material body carries out cryogenic high pressure vacuum heating-press sintering, vacuum tightness≤0.01Pa to element powders in the vacuum heating-press sintering stove on light-duty ball mill, sintering temperature is 550 ℃, sintering time is 3h, and sintering pressure is 80MPa
3) sintered compact that adopts the cryogenic high pressure vacuum heating-press sintering is carried out high temperature solid solution thermal treatment, temperature is 620 ℃, vacuum tightness≤0.01Pa, and sintering time 12h,
4) sample behind the sintering is through hot extrusion, the money mold preheating temperature is 480 ℃ before the extruding, extrusion ratio is 10:1, extruding rate is 1.4m/min, and extrusion carries out one-level solid solution 2h at 470 ℃, is warming up to 485 ℃ of secondary solid solution 2h afterwards, quench in the room temperature water, carry out one-level timeliness 24h at 120 ℃ then, be warming up to 170 ℃ of secondary time effect 1h, be cooled to 120 ℃ of three grades of timeliness 24h.
The void content of the aluminium alloy pipe that makes at last≤0.12%, density are 2.76g/cm
2, the maximum tensile strength 〉=459MPa, hardness value is 〉=175HV.
Embodiment 3
A kind of manufacture method of aldural tubing is characterized in that, comprises the steps:
1) according to following component configuration alloy raw material, Zn 6.4%, and Mg 2.1%, and Cu 2.0%, and Zr 0.24%, and surplus is Al, and each component sum is 100%; Wherein, Al, Zn, Mg, Cu, Zr are the pure element powder of purity more than 99.5%, and alloying ingredient is 10 μ m copper powders, 2 μ m aluminium powders, 20 μ m magnesium powder, 6 ~ 9 μ m zinc powders and 2 ~ 3 μ m zirconium powders.
2) with 150 rev/mins speed ball milling 24h, compound material body carries out cryogenic high pressure vacuum heating-press sintering, vacuum tightness≤0.01Pa to element powders in the vacuum heating-press sintering stove on light-duty ball mill, sintering temperature is 550 ℃, sintering time is 3h, and sintering pressure is 80MPa
3) sintered compact that adopts the cryogenic high pressure vacuum heating-press sintering is carried out high temperature solid solution thermal treatment, temperature is 620 ℃, vacuum tightness≤0.01Pa, and sintering time 12h,
4) sample behind the sintering is through hot extrusion, the money mold preheating temperature is 480 ℃ before the extruding, extrusion ratio is 15:1, extruding rate is 1.4m/min, and extrusion carries out one-level solid solution 2h at 470 ℃, is warming up to 485 ℃ of secondary solid solution 2h afterwards, quench in the room temperature water, carry out one-level timeliness 24h at 120 ℃ then, be warming up to 170 ℃ of secondary time effect 1h, be cooled to 120 ℃ of three grades of timeliness 24h.
The above only is preferred implementation of the present invention, should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention, can also make some improvement, and these improvement also should be considered as protection scope of the present invention.
Claims (1)
1. the manufacture method of an aldural tubing is characterized in that, may further comprise the steps:
1) according to following component configuration alloy raw material, Zn 5.1 ~ 6.4%, and Mg 1.8 ~ 2.1%, and Cu 1.7 ~ 2.0%, and Zr 0.18 ~ 0.24%, and surplus is Al, and each component sum is 100%; Wherein, Al, Zn, Mg, Cu, Zr are the pure element powder of purity more than 99.5%, and alloying ingredient is 10 μ m copper powders, 2 μ m aluminium powders, 20 μ m magnesium powder, 6 ~ 9 μ m zinc powders and 2 ~ 3 μ m zirconium powders,
2) with 150 rev/mins speed ball milling 24h, compound material body carries out cryogenic high pressure vacuum heating-press sintering, vacuum tightness≤0.01Pa to element powders in the vacuum heating-press sintering stove on light-duty ball mill, sintering temperature is 550 ℃, sintering time is 3h, and sintering pressure is 80MPa
3) sintered compact that adopts the cryogenic high pressure vacuum heating-press sintering is carried out high temperature solid solution thermal treatment, temperature is 620 ℃, vacuum tightness≤0.01Pa, and sintering time 12h,
4) sample behind the sintering is through hot extrusion, the money mold preheating temperature is 480 ℃ before the extruding, extrusion ratio is 4:1 ~ 15:1, extruding rate is 1.4m/min, and extrusion carries out one-level solid solution 2h at 470 ℃, is warming up to 485 ℃ of secondary solid solution 2h afterwards, quench in the room temperature water, carry out one-level timeliness 24h at 120 ℃ then, be warming up to 170 ℃ of secondary time effect 1h, be cooled to 120 ℃ of three grades of timeliness 24h.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107695339A (en) * | 2017-10-10 | 2018-02-16 | 浙江跃进机械有限公司 | A kind of preparation method of aluminum base powder metallurgy forging engine link |
| CN107961142A (en) * | 2017-11-02 | 2018-04-27 | 孙艳平 | A kind of medical nursing elbow cane |
| CN107970107A (en) * | 2017-11-02 | 2018-05-01 | 孙艳平 | A kind of nursing leg elasticity crutch |
| CN112899594A (en) * | 2021-02-24 | 2021-06-04 | 东莞冠熹精密五金制品有限公司 | 7003 forging process for aluminum series material |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101818291A (en) * | 2010-04-26 | 2010-09-01 | 中南大学 | Al-Cu-Mg-Ag powdered metallurgical heat-resisting aluminum alloy and preparation method thereof |
| CN102888575A (en) * | 2012-10-22 | 2013-01-23 | 中南大学 | Thermal treatment method for simultaneously improving strength and fatigue resistance property of aluminum alloy |
| CN103233149A (en) * | 2013-04-26 | 2013-08-07 | 张荣森 | High-strength aluminum alloy pipe |
-
2013
- 2013-07-01 CN CN2013102712010A patent/CN103290281A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101818291A (en) * | 2010-04-26 | 2010-09-01 | 中南大学 | Al-Cu-Mg-Ag powdered metallurgical heat-resisting aluminum alloy and preparation method thereof |
| CN102888575A (en) * | 2012-10-22 | 2013-01-23 | 中南大学 | Thermal treatment method for simultaneously improving strength and fatigue resistance property of aluminum alloy |
| CN103233149A (en) * | 2013-04-26 | 2013-08-07 | 张荣森 | High-strength aluminum alloy pipe |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107695339A (en) * | 2017-10-10 | 2018-02-16 | 浙江跃进机械有限公司 | A kind of preparation method of aluminum base powder metallurgy forging engine link |
| CN107961142A (en) * | 2017-11-02 | 2018-04-27 | 孙艳平 | A kind of medical nursing elbow cane |
| CN107970107A (en) * | 2017-11-02 | 2018-05-01 | 孙艳平 | A kind of nursing leg elasticity crutch |
| CN112899594A (en) * | 2021-02-24 | 2021-06-04 | 东莞冠熹精密五金制品有限公司 | 7003 forging process for aluminum series material |
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Application publication date: 20130911 |