In my ASM Al handbook there are CW curves for some alloys. I don't have it at hand so I am not sure if it is exactly what you are looking for. This will depend on the prior heat treat condition, and on what heat treatment you do afterward.
Have you checked the data sheets from Alcoa???
I believe Al has to be fully annealed (-0) to forge the material and once forged I can then temper it to my final requirement..either T-6 or T-8. But I'm curious, does the post tempering negate the strain hardening induced when the material is CW?
First, aluminum alloys can be forged in the -O or -T4 condition; -O will have greater formability than -T4. Second, the heat treatment of aluminum requires solution treating followed by age hardening (precipitation hardening). Solution treating removes any effect of cold working. So, if you use -O for forging, then there will be no increase in strength due to cold working. If you use T4 (already solution treated) then you can cold forge and subsequently age to the T8 condition. This is how many cold forged aluminum parts are manufactured, since the additional strain from forging increases the precipitation kinetics and final strength/hardness.
Thanks...I was concerned that if I cold work the parts if the post process would 'normalize' the material. So I can use T4 and then post age it to T6 or T8 and retain the increase in material strength gained from cold working it. But where does one find the graph that shows increase in material properties for Al 6061 and 7075 vs. %CW?? I have already looked at Alcoa and all that they have shown in the basic material properties...
Also will CWing T4 increase the chances of crack forming on the outer surface...if so is there a general rule of thumb on additional material to account for this so that post machining will be able to remove them. What is the max % you can CW Al say already at T4? Based on what's readily available off the shelf and what I need..I will need to CW by about 83%. I'm concerned at this level I will hardened it too much and cause serious crack to develop... so anybody with experience with aluminum I'd love to hear your comments..
You are asking two questions. Where to find data and whether or no cracks will develop in your application. The answer to your first question is either contact a human being at an aluminum producer like Alcoa (it is not on their website) or find the data in a reference book like ASM HANDBOOK Volume 2 Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM SPECIALTY HANDBOOK: Aluminum and Aluminum Alloys. Here is a link to the latter:
With regards to the second question, you need to provide some additional details in order to get any meaningful answers. How exactly is the metal being deformed? You alluded to forging before: is a cylindrical slug going to be forged? By uniform upsetting? Extrusion? Some combination of the two? Something else? Temperature? Strain rate?
