Method of manufacturing formed pieces of type 2024 aluminum alloy

Abstract

This invention relates to a method of manufacturing highly worked pieces of AlCuMg alloy, comprising the steps of: a) casting a plate composed of (weight per cent): Cu: 3.8-4.5 Mg: 1.2-1.5 Mn: 0.3-0.5 Si<0.25 Fe<0.20 Zn<0.20 Cr<0.10 Zr<0.10 Ti<0.10, b) possibly homogenizing at a temperature between 460 and 510° C. for 2 to 12 hrs, and preferably at a temperature between 470 and 500° C. for a duration for 3 to 6 hrs, c) hot rolling at an input temperature between 430 and 470° C., and preferably between 440 and 460° C., d) cutting out sheets, e) forming in one or several processes, such as stretch forming, drawing, flow spinning, or bending, f) solution treating between 480 and 500° C., for a duration between 5 min and 1 hr, g) quenching, wherein forming can take place before and after solution treatment and quenching. The invention is applicable in particular for manufacturing aircraft fuselage panels.

Description

[0001] This invention relates to a method of manufacturing highly worked pieces for mechanical engineering, and in particular aircraft construction, implementing type 2024 AlCuMg aluminium alloy sheets according to the Aluminum Association's registration.STATE OF THE ART[0002] 2024 alloy is widely used for aircraft construction and its composition registered with the Aluminum Association is as follows (weight per cent): Si<0.5 Fe<0.5 Cu: 3.8-4.9 Mn: 0.3-0.9 Mg: 1.2-1.8 Zn<0.25 Cr<0.10 Ti<0.15.[0003] In addition to the characteristics usually required for aircraft construction, such as high mechanical strength, toughness, resistance to crack propagation, etc., certain pieces, especially those made by stretch forming, drawing, flow spinning, bending or roll forming, require sheets with good forming ability.[0004] Patent EP 0 473 122 describes a method of manufacturing alloy sheets composed of (weight per cent): Cu: 4-4.5 Mg: 1.2-1.5 Mn: 0.4-0.6 Fe<0.12 Si<0.05, in...

AI Technical Summary

Benefits of technology

[0027] Preferably, the alloy has a copper content between 3.9 and 4.3% (and even more preferably between 3.9 and 4.2%), a magnesium content between 1.2 and 1.4% (and even more preferably between 1.25 and 1.35%), a manganese content between 0.3 and 0.45%, an iron content of <0.10%, a silicium content of <0.10% (and preferably <0.08%), a titanium, chromium and zirconium content of <0.07% (preferably <0.05%). The inventive method allows for possibly using cladded plates, e.g. sheets coated with a cladding of an alloy having better corrosion resistance, as is the case usually for aircraft fuselage coating sheets.

Problems solved by technology

However, this additional and unusual process step has economic drawbacks.

Furthermore, it does not solve the problem posed by the market, i.e. to supply sheets with characteristics such that the forming thereof be simplified.

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