Metal treatment – Process of modifying or maintaining internal physical... – Heating or cooling of solid metal
Reexamination Certificate
2002-06-05
2004-01-20
Wyszomierski, George (Department: 1742)
Metal treatment
Process of modifying or maintaining internal physical...
Heating or cooling of solid metal
C148S694000, C148S702000
Reexamination Certificate
active
06679958
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) FIELD OF THE INVENTION
The invention relates to a heat treatable AL—Mg—Si aluminium alloy which after shaping has been submitted to an ageing process, which includes a first stage in which the extrusion is heated with a heating rate above 30° C./hour to a temperature between 100-170° C., a second stage in which the extrusion is heated with a heating rate between 5 and 50° C./hour to the final hold temperature between 160 and 220° C. and in that the total ageing cycle is performed in a time between 3 and 24 hours.
(2) DESCRIPTION OF THE RELATED ART
A process for ageing aluminum alloys containing magnesium and silicon (Al—Mg—Si) is described in WO 95.06769. According to this publication the ageing is performed at a temperature between 150 and 200° C., and the rate of heating is between 10-100° C./hour preferably 10-70° C./ hour. As an alternative to this, a two-step heating schedule is proposed, wherein a hold temperature in the range of 80-140° C. is suggested in order to obtain an overall heating rate within the above specified range.
BRIEF SUMMERY OF THE INVENTION
The present invention provides an ageing process capable of producing an aluminum alloy which has better mechanical properties than possible with traditional ageing procedures and shorter total ageing times than with the ageing practise described in WO 95.06759. More particularly, the ageing process of this invention employs a dual rate heating technique that comprises a first stage in which the aluminum alloy is heated at a first heating rate to a temperature between 100 and 170° C. and a second stage in which the aluminum alloy is heated at a second heating rate to a hold temperature of 160 to 220° C. The first heating rate is at least 100° C./hour and the second heating rate is 5 to 50° C./hour. The entire ageing process is performed in a time of 3 to 24 hours. With the proposed dual rate ageing procedure of this invention, the strength of the alloy can be maximized using a minimum total ageing time.
REFERENCES:
patent: 6440359 (2002-08-01), Parson et al.
patent: WO 9506759 (1995-03-01), None
Oddvin Reiso
Tundal Ulf
Combs Morillo Janelle
Hartman Domenica N. S.
Hartman Gary M.
Hartman & Hartman, P.C
Norsk Hydro
LandOfFree
Process of aging an aluminum alloy containing magnesium and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of aging an aluminum alloy containing magnesium and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of aging an aluminum alloy containing magnesium and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3235944