aluminum Ingot vs as cast properties
aluminum Ingot vs as cast properties
(OP)
I have a customer testing thread rolling and machine screws in aluminum ingots and getting lots of variability in the results. They reported that prior tests conducted in castings (engine blocks) worked well. The material is the same.
Materials are ADC10 (no heat treatment) ADC10-T5 and AC2B-T7 (Customer is in Korea).
I suspect that testing in ingots is not valid, but can't state a definitive reason. I suspect porosity perhaps.
Can anyone state if testing the screws (for torque) in ingots is, or is not, valid and any possible reasons?
Thanks
JR
Materials are ADC10 (no heat treatment) ADC10-T5 and AC2B-T7 (Customer is in Korea).
I suspect that testing in ingots is not valid, but can't state a definitive reason. I suspect porosity perhaps.
Can anyone state if testing the screws (for torque) in ingots is, or is not, valid and any possible reasons?
Thanks
JR





RE: aluminum Ingot vs as cast properties
RE: aluminum Ingot vs as cast properties
thanks for the response!
John
RE: aluminum Ingot vs as cast properties
Also as TVP indicated,the section thickness variation in the two will influence shrinkage porosity.
An ingot is cast for eventual forging,rolling or extruding operations. thus gating,feeding techniques and mold quality is not of primary concern. The liquid metal quality may be same as processing conditions are different,the end result is bound to vary.
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"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year
RE: aluminum Ingot vs as cast properties
RE: aluminum Ingot vs as cast properties
_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year
RE: aluminum Ingot vs as cast properties
The size of the ingot is 8" x 16" x 3 1/4". They have agreed that this material is not valid for testing. the worse results were obtained in the middle of the ignot (no surprise there).
Arumrao, I can't answer fully on using round rods, but perhaps they are not available in the cast materials to be used.
Unfortunately, someone did not crunch some number before completeing the tests. If I saw negative - 3 sigma values, I would have stopped all testing. Unfortantely they ran about 400 tests and another facility ran extensive thermal tests
RE: aluminum Ingot vs as cast properties
It is clear to me that ingot was a poor substitute for the engine block. The solidication conditions will be completely different for the two, which means that the microstructure will be different, which means the mechanical properties will be different, and the amount and location of porosity also will be different. I also agree with your assessment that testing 30 fasteners should produce a reasonable result, which is an obvious indicator that the ingot was not a suitable sample for evaluation. Good luck.
RE: aluminum Ingot vs as cast properties
Thanks all.