Any Experiences Forming 7150-T77511 Extrusion??? 1

[WKTaylor]

Folks...

Anyone had experience forming 7150-T77511 extrusion [T/R ratio = or >100]... such as a typical "T" section???

On one hand I am being told:

a) it is "impossible" [IE: it is too "brittle", many cracking failures when formed "cold" or "hot". Folks seem pretty sure forming will have severe adverse affects on handbook design allowables!?!?!

b) it is difficult, but can be done using "hot-forming" methods. Caution: residual stresses will affect dimensional stability for machining. And a SMALL percentage may fail penetrant testing. Folks seem unsure as to affects on handbook design allowables!?!?!

c) the vendor [ALCOA] can stretch[~1.5%]-then-form it in "W" temper NTE 3% stretch]... and apply proprietary Precip-Heat Treatments [to meet -T77511 requirements] and the part will have very low residual stresses while meeting all handbook design allowables.

What are Your experiences???? Any words of wisdom???






Regards, Wil Taylor

 

[GregLocock]

I haven't used that material, but we did use 6061. the tool was designed by our vendor to produce the finished form required (basically a half cylindrical shell, of about the dimensions of an automotive main bearing shell, or a little thinner).

The results were excellent, and very cheap. I think the tool only cost a thousand bucks. The accuracy was superb.

So my advice is that if the vendor has experience in that field then follow his advice.

Cheers

Greg Locock