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US20090047172A1 - Extrudable Al-Mg-Si alloys - Google Patents

Extrudable Al-Mg-Si alloys Download PDF

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Publication number
US20090047172A1
US20090047172A1 US12/288,022 US28802208A US2009047172A1 US 20090047172 A1 US20090047172 A1 US 20090047172A1 US 28802208 A US28802208 A US 28802208A US 2009047172 A1 US2009047172 A1 US 2009047172A1
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Prior art keywords
alloy
alloys
extrusion
ageing
ingot
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US12/288,022
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English (en)
Inventor
Hang Lam Yiu
Ricky Arthur Ricks
Stephen Anthony Court
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Priority to US12/288,022 priority Critical patent/US20090047172A1/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/043—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with silicon as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent

Definitions

  • This invention concerns intermediate strength extrudable Al—Mg—Si alloys, in the 6000 series of the Aluminum Association Register.
  • the dilute Al—Mg—Si alloys with levels of the two primary alloying additions at less than approximately 0.50 wt. %, are used extensively in extruded form in many market sectors, including architectural (doors, window frames, etc.) and structural applications.
  • These alloys generally lie within the AA6063 specification, which has compositional limits for Mg and Si of 0.45 to 0.90 wt. % and 0.20 to 0.60 wt. % respectively.
  • These alloys are capable of producing complex sections which are readily air quenchable off the press and which may be extruded at high exit speeds whilst maintaining a very high quality surface finish; attributes which are associated with high extrudability.
  • this invention is concerned with alloys of composition in weight %
  • FIG. 1 of the accompanying drawings is a compositional plot showing the Mg and Si specification ranges for various alloys in the Aluminum Association specification.
  • the filled circle shows the nominal composition of alloys according to the present invention, and the rectangle round it corresponds to the above definition. It can be seen that the above defined alloy composition does not overlap with any of the AA designated alloys shown.
  • the alloys of the present invention are high excess Si alloys.
  • the nominal composition of these alloys (marked by the filled circle in FIG. 1 ) is set out in the table below, together with the nominal compositions of AA6106 which is an excess Si alloy, and of AA6063A which is a balanced alloy.
  • An alloy of balanced composition is one in which just enough Si is present to combine with all the Mg, Fe, Mn as Mg 2 Si and Al(Fe,Mn)Si.
  • Nominal Composition Alloy Si Mg Fe Invention 0.70 0.35 0.2 AA6106 0.6 0.5 0.2 AA6063A 0.5 0.63 0.2
  • the alloys of this invention have a number of advantages. It should be understood that not all the stated advantages are necessarily achieved by all the alloys. Also, a particular property may not be an improvement on some other alloy. But most of the advantages are possessed by most alloys according to the invention, and it is this combination that represents a significant advance in the art:
  • Extrusion ingots of the alloys are capable of being extruded at relatively high speeds, typically around 75% of the maximum extrusion speed of AA6063 alloys.
  • extrusion pressures required are lower than for AA6063 alloys, which reduces equipment and operating costs.
  • the extrusions are air quenchable.
  • the extrusions have a surface quality which is acceptable for most architectural applications.
  • the surface quality of the extrusions can be made to be better than for any related alloy compositions.
  • the extrusions are capable of being aged to a tensile strength in excess of 240 MPa, often in excess of 250 MPa, with acceptable toughness.
  • a two-stage or ramped ageing process is particularly effective in improving aged properties.
  • the Mg content of the invention alloy is set at 0.25-0.40%. If the Mg content is too low, it is difficult to achieve the required strength in the aged extrusions. Extrusion pressure increases with Mg content, and becomes unacceptable at high Mg contents.
  • the Si content is set at 0.6-0.9%. If the Si content is too low, the alloy strength is adversely affected, while if the Si content is too high, extrudability may be reduced.
  • the function of the Si is to strengthen the alloy without adversely affecting extrudability, high temperature flow stress, or anodising and corrosion characteristics.
  • Fe is not a desired component of the alloy, but its presence is normally unavoidable.
  • An upper concentration limit is set at 0.35%, and a preferred range at 0.15-0.35% (because alloys containing less Fe are more expensive).
  • Fe is present in the form of large plate-like ⁇ -AlFeSi particles.
  • the extrusion ingot is homogenised to convert ⁇ -AlFeSi to the ⁇ -AlFeSi form. It is known however that excess Si (over the amount required to form Mg 2 Si) stabilises the ⁇ -AlFeSi phase, which has a detrimental effect on extrudability and in particular on extrusion surface quality. Where extrusion surface quality is important, this problem may be avoided by homogenising the extrusion ingot under special conditions or by modifying the alloy composition.
  • Mn is included in the alloys in order to improve extrusion surface quality.
  • Mn acts to accelerate the ⁇ to ⁇ -AlFeSi transformation during homogenisation, so that the resulting homogenised ingot has improved extrudability, that is to say improved extrusion surface quality.
  • Any Mn addition is beneficial in this way and improvements may be seen with additions as low as 0.05% or 0.07%. Above 0.35% Mn, further improvements are not seen, or are not commensurate with the added cost, and the extrudates may show increased quench sensitivity.
  • a preferred Mn content is 0.10-0.25%.
  • the Si is present as Mg 2 Si and some more is present as AlFeSi.
  • the excess Si over the amount required to combine with all the Mg and Fe present, is at least 0.3%.
  • An extrusion ingot of the alloy of the invention may be made by any convenient casting technique, e.g. by a DC casting process preferably by means of a short mould or hot-top DC process.
  • the Fe is preferably present as an insoluble secondary phase in the form of fine ⁇ -AlFeSi platelets preferably not more than 15 ⁇ m in length or, if in the ⁇ form, free from script and coarse eutectic particles.
  • the as-cast extrusion ingot is homogenised, partly to bring the soluble secondary magnesium-silicon phases into suitable form, and partly to convert ⁇ -AlFeSi particles into ⁇ -AlFeSi particles, preferably below 15 ⁇ m long and with 90% below 6 ⁇ m long.
  • Homogenisation typically involves heating the ingot at 550-600° C. for 30 minutes to 24 hours, with higher temperatures requiring shorter hold times. As noted above, optimum homogenisation conditions may depend on the presence and concentration of added Mn.
  • the homogenised extrusion ingot is hot extruded, under conditions which may be conventional.
  • the emerging extrusion is quenched, either by water or forced air or more preferably in still air, and subjected to an ageing process in order to develop desired strength and toughness properties.
  • Ageing typically involves heating the extrusion to an elevated temperature in the range 150-200° C., and holding at that temperature for 1-48 hours, with higher temperatures requiring shorter hold times.
  • a surprising feature of this invention is that the response of the extrusion to this ageing process depends significantly on the rate of heating.
  • a preferred rate of heating is from 10-100° C., particularly 10-70° C., per hour; if the heating rate is too slow, low throughput results in increased costs; if the heating rate is too high, the mechanical properties developed are less than optimum.
  • An effect equivalent to slow heating can be achieved by a two-stage heating schedule, with a hold temperature typically in the range of 80-140° C., for a time sufficient to give an overall heating rate within the above range.
  • extrusions When aged to peak strength, extrusions are typically found to have an ultimate tensile strength of at least 240 MPa, often greater than 250 MPa, with acceptable toughness.
  • FIG. 1 is a compositional plot showing the Aluminum Association specification ranges for Mg and Si for various alloys alongside the alloys of the present invention (the blank rectangle containing the filled circle).
  • FIG. 2 is a bar diagram showing the effect of alloy composition and homogenisation temperature on the maximum extrusion pressure of 250 MPa target alloys extruded into a 5 ⁇ 20 mm section.
  • FIG. 3 is a bar diagram showing the effect of alloy composition and homogenisation temperature on the surface roughness measurement of 250 MPa target alloys extruded into a 5 ⁇ 20 mm section.
  • FIG. 4 is a bar diagram showing the effect of alloy composition and homogenisation temperature on 20° gloss (reflectivity) measurement of 250 MPa target alloys extruded into 5 ⁇ 20 mm section.
  • FIG. 5 is a bar diagram showing the effect of alloy composition on the mechanical properties of 250 MPa target alloys, which had been homogenised for 2 hours at 580° C., extruded into a 5 ⁇ 20 mm section, forced air quenched, and aged for 7 hours at 175° C. The properties were measured at the back of the extrusion.
  • FIG. 6 is a graph showing the effect of ramp rate to the ageing temperature (5 hours at 185° C.) on the tensile strength of two dilute 6000 series alloys, including a very high excess Si alloy containing no Mn and having a composition within the scope of the present invention.
  • FIG. 7 is a bar diagram showing surface roughness of the alloys extruded in Example 4.
  • FIG. 8 is a bar diagram showing tensile properties of the alloys extruded in Example 4.
  • the invention has been tested in the laboratory. Extrusion trials were carried out using an experimental extrusion press, in which the alloys given in Table 1 below were extruded. These alloys represent a low Mg-containing alloy of the invention, with and without an addition of 0.12% Mn, together with typical AA6063 and AA6106 compositions, again with and without an addition of about 0.12% Mn.
  • the nominal alloy composition of the invention is shown as a filled circle in the compositional plot of FIG. 1 .
  • Extrusion ingots were DC cast and were homogenised for 2 hours at 570° C. or 580° C. They were then hot extruded.
  • the surface quality of the extrudate was assessed using both profilometry and Gloss (reflectivity) measurements, and the data obtained using these techniques are given in FIGS. 3 and 4 . From FIG. 3 , it can be seen that the lowest value of mean surface roughness (Ra), for a given homogenisation condition, is produced in extrudate from the optimum alloy composition of the invention (the low Mg, Mn-containing alloy). The same alloy also gives the highest Gloss measurement, again for a given homogenisation treatment. Therefore, the alloy of the invention has been shown to have the best surface quality of the alloys evaluated.
  • Ra mean surface roughness
  • the tensile properties and Kahn tear toughness of the extrudate from each alloy was evaluated following “peak” ageing (7 hours at 175° C.), and the relevant data are shown in FIG. 5 . It can be seen from this figure that the tensile properties and the toughness of the alloy of the invention are equivalent to those of the AA6106 and AA6063A alloys.
  • the invention has been tested on a commercial scale. Extrusion trials were carried out using 180 mm diameter billets. The compositions of the trial alloys are given in Table 3.
  • the experimental alloy of the invention has properties equivalent to the AA6063A alloy, and their tensile strength well in excess of 250 MPa with acceptable toughness.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Extrusion Of Metal (AREA)
  • Powder Metallurgy (AREA)
  • Glass Compositions (AREA)
US12/288,022 1993-08-31 2008-10-15 Extrudable Al-Mg-Si alloys Abandoned US20090047172A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/288,022 US20090047172A1 (en) 1993-08-31 2008-10-15 Extrudable Al-Mg-Si alloys

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB9318041.2 1993-08-31
GB939318041A GB9318041D0 (en) 1993-08-31 1993-08-31 Extrudable a1-mg-si alloys
PCT/GB1994/001880 WO1995006759A1 (fr) 1993-08-31 1994-08-30 ALLIAGES DE Al-Mg-Si SUSCEPTIBLES D'ETRE EXTRUDES
US60101096A 1996-02-23 1996-02-23
US12/288,022 US20090047172A1 (en) 1993-08-31 2008-10-15 Extrudable Al-Mg-Si alloys

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
PCT/GB1994/001880 Continuation WO1995006759A1 (fr) 1993-08-31 1994-08-30 ALLIAGES DE Al-Mg-Si SUSCEPTIBLES D'ETRE EXTRUDES
US60101096A Continuation 1993-08-31 1996-02-23

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US20090047172A1 true US20090047172A1 (en) 2009-02-19

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US12/288,022 Abandoned US20090047172A1 (en) 1993-08-31 2008-10-15 Extrudable Al-Mg-Si alloys

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Country Link
US (1) US20090047172A1 (fr)
EP (1) EP0716716B2 (fr)
JP (1) JPH09501987A (fr)
AT (1) ATE169689T1 (fr)
AU (1) AU680679B2 (fr)
BR (1) BR9407462A (fr)
CA (1) CA2169968C (fr)
DE (1) DE69412491T3 (fr)
GB (1) GB9318041D0 (fr)
NO (1) NO960808L (fr)
NZ (1) NZ271423A (fr)
WO (1) WO1995006759A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU725909B2 (en) * 1997-03-21 2000-10-26 Alcan International Limited Al-Mg-Si alloy with good extrusion properties
WO1998042884A1 (fr) * 1997-03-21 1998-10-01 Alcan International Limited Alliage d'aluminium, de magnesium et de silicium possedant de bonnes qualites d'extrusion
DK1155156T3 (da) * 1999-02-12 2003-08-04 Norsk Hydro As Aluminiumslegering indeholdende magnesium og silicium
US6679958B1 (en) * 1999-02-12 2004-01-20 Norsk Hydro Process of aging an aluminum alloy containing magnesium and silicon
BG65068B1 (bg) * 2001-08-09 2007-01-31 Norsk Hydro Asa Метод за обработване на алуминиева сплав, съдържаща магнезий и силиций
NO20034731D0 (no) * 2003-10-22 2003-10-22 Norsk Hydro As Aluminiumslegering
WO2006056481A1 (fr) * 2004-11-25 2006-06-01 Corus Aluminium Nv Feuille d'alliage a base d'aluminium pour des applications dans l'industrie automobile
JP5153659B2 (ja) * 2009-01-09 2013-02-27 ノルスク・ヒドロ・アーエスアー マグネシウム及びケイ素を含有するアルミニウム合金の処理方法

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3879194A (en) * 1971-05-25 1975-04-22 Alcan Res & Dev Aluminum alloys
US3926690A (en) * 1972-08-23 1975-12-16 Alcan Res & Dev Aluminium alloys
US4256488A (en) * 1979-09-27 1981-03-17 Swiss Aluminium Ltd. Al-Mg-Si Extrusion alloy
US4729939A (en) * 1985-07-25 1988-03-08 Nippon Light Metal Company Limited Aluminum alloy support for lithographic printing plates
US4808247A (en) * 1986-02-21 1989-02-28 Sky Aluminium Co., Ltd. Production process for aluminum-alloy rolled sheet
US4814022A (en) * 1986-07-07 1989-03-21 Cegedur Societe De Transformation De L'aluminum Pechiney Weldable aluminum alloy workable into sheet form and process for its production
US5223050A (en) * 1985-09-30 1993-06-29 Alcan International Limited Al-Mg-Si extrusion alloy
US5525169A (en) * 1994-05-11 1996-06-11 Aluminum Company Of America Corrosion resistant aluminum alloy rolled sheet
US5571347A (en) * 1994-04-07 1996-11-05 Northwest Aluminum Company High strength MG-SI type aluminum alloy
US5690758A (en) * 1993-12-28 1997-11-25 Kaiser Aluminum & Chemical Corporation Process for the fabrication of aluminum alloy sheet having high formability
US6440359B1 (en) * 1997-03-21 2002-08-27 Alcan International Limited Al-Mg-Si alloy with good extrusion properties

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6049707B2 (ja) * 1977-08-16 1985-11-05 住友アルミニウム製錬株式会社 薄肉押出形材の製造方法
DE3243371A1 (de) * 1982-09-13 1984-03-15 Schweizerische Aluminium AG, 3965 Chippis Aluminiumlegierung
JPS61136650A (ja) * 1984-12-05 1986-06-24 Sumitomo Alum Smelt Co Ltd 押出性、曲げ加工性の優れた中強度アルミニウム合金
GB8524077D0 (en) * 1985-09-30 1985-11-06 Alcan Int Ltd Al-mg-si extrusion alloy
BE906107A (fr) * 1986-12-30 1987-04-16 Alusuisse Alliage a base d'aluminium.
DE69107392T2 (de) * 1990-10-09 1995-06-08 Sumitomo Light Metal Ind Verfahren zur Herstellung eines Werkstoffes aus eines Aluminiumlegierung mit ausgezeichneter Pressverformbarkeit und Einbrennhärtbarkeit.

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3879194A (en) * 1971-05-25 1975-04-22 Alcan Res & Dev Aluminum alloys
US3926690A (en) * 1972-08-23 1975-12-16 Alcan Res & Dev Aluminium alloys
US4256488A (en) * 1979-09-27 1981-03-17 Swiss Aluminium Ltd. Al-Mg-Si Extrusion alloy
US4729939A (en) * 1985-07-25 1988-03-08 Nippon Light Metal Company Limited Aluminum alloy support for lithographic printing plates
US5223050A (en) * 1985-09-30 1993-06-29 Alcan International Limited Al-Mg-Si extrusion alloy
US4808247A (en) * 1986-02-21 1989-02-28 Sky Aluminium Co., Ltd. Production process for aluminum-alloy rolled sheet
US4814022A (en) * 1986-07-07 1989-03-21 Cegedur Societe De Transformation De L'aluminum Pechiney Weldable aluminum alloy workable into sheet form and process for its production
US5690758A (en) * 1993-12-28 1997-11-25 Kaiser Aluminum & Chemical Corporation Process for the fabrication of aluminum alloy sheet having high formability
US5571347A (en) * 1994-04-07 1996-11-05 Northwest Aluminum Company High strength MG-SI type aluminum alloy
US5525169A (en) * 1994-05-11 1996-06-11 Aluminum Company Of America Corrosion resistant aluminum alloy rolled sheet
US6440359B1 (en) * 1997-03-21 2002-08-27 Alcan International Limited Al-Mg-Si alloy with good extrusion properties

Also Published As

Publication number Publication date
EP0716716B2 (fr) 2004-12-29
WO1995006759A1 (fr) 1995-03-09
DE69412491T2 (de) 1998-12-24
CA2169968C (fr) 2006-08-29
EP0716716A1 (fr) 1996-06-19
CA2169968A1 (fr) 1995-03-09
NO960808D0 (no) 1996-02-28
JPH09501987A (ja) 1997-02-25
ATE169689T1 (de) 1998-08-15
EP0716716B1 (fr) 1998-08-12
AU7504694A (en) 1995-03-22
DE69412491T3 (de) 2005-07-07
DE69412491D1 (de) 1998-09-17
NO960808L (no) 1996-02-28
GB9318041D0 (en) 1993-10-20
NZ271423A (en) 1997-11-24
BR9407462A (pt) 1996-11-12
AU680679B2 (en) 1997-08-07

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