huangyhg

aluminum material callout on drawing
this may be a very simple question, but i couldn't find anything on it. i am checking a drawing of a simple bracket made out of aluminum 6061. the designer doesn't want a heat treatment, and as such, has listed them material as al 6061. i don't think i've ever seen a drawing without a heat treatment callout for aluminum, so i was wondering if this is correct, or if there is any specific way to put it on the drawing, that the aluminum doesn't require any treatment.
any and all help is appreciated.
v
mechanical engineer
"when i am working on a problem, i do not think of beauty, but when i've finished, if the solution is not beautiful, i know it is wrong."
- r. buckminster fuller
as a minimum, the alloy needs to state the temper by dash number. -t0 (0 temper) is the untempered state, but since -t6 is a common stock item, without need for subsequent tempering, i would consider that.
just listing 6061 would probably imply that any heat treat grade of 6061 was acceptable. as 6061-t6 is probably most common, that's what you'd likely end up with.
is 6061-o what your designer actually intends?
also, fyi i believe 6061 may naturally age to around t4 condition over time.
if the call out is alum alloy 6061, the machinist is allowed to use any temper. but as checkerron pointed out, i would use alum 6061-t6, or whatever temper is req'd.
chris
solidworks 08 0.0/pdmworks 08
autocad 06
pet peeve time...
there is no such alloy as "alum alloy 6061". alum is potassium aluminum sulfate kal(so4)2·12h2o or an ammonium aluminum sulfate nh4al(so4)2·12h2o used especially as an emetic and as an astringent and styptic. way too soft for machining
i know that this is nit-picking, but it is a very simple matter to use the correct abbreviation. a drawing should be able to be read literally without assumptions, and using alum as an abbreviation is an assumption that the reader will know to actually use aluminum, as remote as that possibility may be.
well for that matter isn't it aluminium
i thought i was the only one that got upset by incorrect abbreviations.
vc66, is using 6061 without heat treat driven by function?
kenat, probably the least qualified checker you'll ever meet...
i agree ewh.
i don't have all abbrev memorized. for forum's sake, i use whatever is on top of my head or what the poster is using. it is up to the engineer questioning to find the proper abbrev, and i'm not going to look it up unless the question is asked.
chris
solidworks 08 0.0/pdmworks 08
autocad 06
i don't have to look that one up... i was pinged on it in my first detailing job (on the board) and it's stuck with me.
as to the other posts, i agree. if only al 6061 is called out, that leaves the door open to use any temper of 6061.
vc66,
why not just call up aluminium, and forget the alloy?aluminium 6061-0 has a yield stress of 8000psi. it is not much stronger than aluminium 1000. a fabricator probably would prefer to machine heat treated 6061. if he is doing sheet metal, he will prefer 1000 or 5052.
i agree with the idea that we should not specify things that are not necessary, but let us take it to its logical conclusion.
jhg
the intent of the bracket isn't really load-bearing, just positional. therefore, he doesn't care about strength. seeing as though al 6061-t6 is probably the most common, which i also believe we do stock, i'll tell him to use that, but thanks for all the replies.
furthermore, i said al (elemental name for aluminum), so don't yell at me...
v
mechanical engineer
"when i am working on a problem, i do not think of beauty, but when i've finished, if the solution is not beautiful, i know it is wrong."
- r. buckminster fuller
ah, so i was mislead by your op.
you said "the designer doesn't want a heat treatment" when it sounds as if you meant "the designer doesn't require any specific heat treatment".
in this case there are 2 schools of thought.
1. just put aluminum alloy (or an approved abbreviation there-of) as drawoh suggests.
this assumes the vendor/machine shop will use the 'cheapest' grade available and hence give you the best cost (note it may not actually be the cheapest grade, it may be some overstock material they have and want to get rid of etc.) some argue that you're not properly specifying the part but i'm not sure that asme y14 series says anything about this (please let me know if it does).
2. always specify a grade as otherwise the machine shop can pick and may deliberately choose high grade material they have on hand and charge you accordingly.
i have only heard point 2 at my current employer, never before. i tend to think it's kind of dumb but, because we don't competatively tender or really estimate most jobs it could happen and i doubt the purchasing director at the time just made it up.
in government work of course you usually have to put not only the grade but also the controlling spec on the drawing, at least in the uk we did.
kenat, probably the least qualified checker you'll ever meet...

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