ASTM B918

[AEKen]

We are heat treating some forged aluminum parts from T6 to T73 and ASTM B918 is confusing. Can someone clarify the process for us:

The ASTM B918 calls for the following:
Annealing 860-900F for 1.5 to 2 hours (does it matter which 1.5 or 2 hours?)
Quench 140-160F
Aging for T73 225F for 6-8 hours then cool over time

That is it right?

There is mention of another 350F for 6-8 hours but that seems redundant.

Can some calcify exactly what HT process we need for the best strength and anti corrosion features.

Thank you.

 

[TVP]

AEKen,

For the solution heat treatment time, did you consult Table 3 of ASTM B918? The time depends on the thickness of the part. Regarding T73 precipitation treatment, this is a 2-stage process that must be performed in the correct order:

1st precipitation treatment is 215-235 F for 6 to 8 hours followed by
2nd precipitation treatment at 340-360 F for 8 to 10 hours