Stainless steel questions

[szzuk]

How would I best change the thickness of stainless steel? For example, if I bought some with a thickness of 0.25mm how would I best change this to 0.23mm. I would like to test 0.21mm - 0.24mm but it is only available in 0.20mm or 0.25mm.

How do I test the hardness of stainless steel? For example if I bought some that was 0.25mm, how would I know it was half hard, full hard etc. with more accuracy than a bending it by hand.

Ultimately the purpose of this is to make a stainless steel disc with a resonant frequency of 50KHz for a piezo buzzer. Changing the diameter is relatively easy so doing that isn't a major problem but I think I may need for example 15mm diameter disc with a thickness of 0.22mm and a hardness of "xyz". The stainless grade is 304/316.

Regards.

[Gordon]

Hi szzuk

For hardness testing, I think a microhardness tester using Vickers or Knoop.

As for reducing thickness, I think Rolling sheet metal work will be required.

[szzuk]

Hi Gordon,

Do you know if I could buy a hardness testing kit relatively cheaply? I don't need enormous accuracy, probably £100 or $150 would be the limit. The parts I need to test are 15mm diameter and thickness <0.3mm so I think something suitable may be available.

Thanks,

Szzuk.