Home Forums General Discussion Media, Shot, Beads, etc. Conditioned Cut Wire v Cast Shot

Hi

We are having a debate with our supplier/consultant reference the correct alternative Conditioned Cut Wire Shot to Cast Shot.

Our general requirements are as below, but we have the option to use Cut Wire shot:

10-16 Almen C S-330 to S-780
14-20 Almen A S-110 to S-330

Specification AMS2430 + J441 give the following as a CW alternative:

S110 CW 14
S330 CW 41
S780 CW 96

Although our consultant says that these are the correct CW alternative to the CS requirements, the shot supplier has stated that they are not.
Could this be because the performance characteristics of CW are different to that of CS and therefore a smaller size is required, I am not sure.

Has anyone any information to assist us?

First no way are you going to get a 14-20A using 110 shot 10A is the highest you should go. The velocity necessary to go higher would be extreme and you are no longer peening. You would be abusing the part surface,

In your post you are only comparing sizes. Are they also of equivalent hardness? If not there is your problem.

Are you allowed to substitute CCW for Cast Steel shot? AMS 2430 does not give you permission to do so, it just shows what is equivalent.

Yes appreciate S110 will not achieve 14A therefore we could use S330 as that is what our customer specification states.

The specification as a 'get out clause' as it says the shot type is optional to the service provider as long as Almen intensity and degradation of surface finish are respected. We are choosing to use CW so that we do not need to decontaminate

So your using stainless steel conditioned cut wire?

What exactly is your consultant and supplier in disagreement over?

If you are switching from cast steel to CCW you will need to re-run your saturation curves as they do not perform exactly the same. CCW is superior to cast steel in every way except one. The surface finish on your part will be somewhat rougher regardless of the amount of conditioning.

Sorry probably not explained myself well. At present we do not do any shotpeening, we have a new machine which is to be commissioned soon, and therefore we have yet to run any saturation curves.

The disagreement is that our customers specification states a typical shot size and intensity as stated in my first post, but we will not be using cast shot so are looking for the CW alternative. The consultant is refereing to ASM2430 & J441 for the CW equivalent to our customer typical shot type and therefore states:

S780 = CW96 (2.4mm)
S330 = CW41 (1.0mm)
S110 = CW14 (0.35mm)

Whereas the shot supplier is stating:

S780 = 2.0mm
S330 = 0.8mm
S110 = 0.4mm

First new CCW is sold by weight not sieve size. CCW14 is approximately .0139” and larger as a test sieve size. Cast Steel is sold by sieve size and the size designation (S-110) is the approximate size in inches. CS S-110 has 90% of the particles larger than .0117” and can have no more than 50% of the particles larger than .0139”; typically 20% larger. So if you refer to Table 1, Size requirements of in-process media, in AMS2430, these different media must be maintained in a peen process using the requirements. S-110 vs. CCW 14. This attachment is not a cross reference guide. So your assumptions on the sizes show above CS vs. CCW is correct they are approximately the same size but do not just change without re-running your saturation curves.