Home Forums General Discussion Shot Peening Process, Intensity, Coverage Magnetism Through Shot Peening

Morning

Would you expect to experience any magnetism of the parts through shot peening using Conditioned Cut Wire Stainless Steel Shot?

No

Many thanks for your quick reply Jack, what about in the media itself?

My answer would be the same as Jack's if the component itself is non-magnetic e.g. aluminum. If, on the other hand, it is ferromagnetic then some transfer of magnetism (shot to component) can occur. This requires, however, that the conditioned cut wire stainless steel shot itself has some magnetism. During conditioning some stainless steels generate a fraction of martensite (due to plastic deformation). This fraction can itself become slightly magnetized. Demagnetization of shot can then be effected by, for example, vigorous shaking.

The chance that the media itself can become magnetized is summarized in the above post from Socrates. Stainless steel cut wire media can be made from several grades of stainless steel, some can transition into martensite easier than others.

Again many thanks for your information. The material I am refering to is 301 Stainless manufacture and conditioned in line with AMS 2431/4C.

After a little googling I found the 301 becomes magnetic when cold worked, but AMS 2431 doesn't call for any demagnetization.

With this being the case, we appear to have a magnetic field within our media, need to now check if this is in anyway transferred to the non-magnetic parts we are peening!

Thanks for additional information. In fact we are investigating the magnetizing effect of SS cut wire ourselves. I doubt that it will magnetize your parts but I would like to learn your results and conclusions.

It will probably be a couple of weeks, but I will let you know how we get on

As previously stated, most austenitic stainless steels can become magnetic during coldworking, such as shotpeening.

Nickel and nitrogen are austenite stabilizers so an alloy like 301 with a relatively low nickel content is expected to have a higher magnetic permeability. If you are allowed a different grade of stainless, the amount of magnetism may be reduced.