Dear Mr. Jack Champaigne:

Hello!

We have a wheel which is made by Al alloy, it needs to be shotpeened. It is required to used the ceramic bead to shotpeening the wheel, the intensity is 0.07 ¨C 0.14 mm, ceramic shot diameter is 0.25 mm - 0.42 mm, the coverage is 100% in its manual. Can we use the cast steel shot (shot size : s170) to shotpeening the wheel ? Do you know if it can be exchanged for Cast Steel Shot and Ceramic Bead ?

No, you should NOT substitute to cast steel shot unless you have specific permission from the customer. Here are some reasons:
1. Density difference between cast steel and ceramic is significant and therefore the results (compression stress zone in wheel and fatigue performance) could be very different.
2. Cast steel shot will leave a ferrous residue on the wheel surface which will turn to rust. Ceramic bead will not cause this problem.
3. There may be a difference in appearance of the surface between using cast steel shot and ceramic and the customer may be expecting the appearance created only by the ceramic bead.