Shot peening

Shot peening hammers a surface with shot hard enough to leave compressive residual stress and a controlled dimple field. It is not the same blast used to roughen a part for spray, even if both make a gray noise.

Fatigue-sensitive fillets on shafts, gears, and landing-gear cousins in aerospace are why the machine exists. Intensity, coverage, and shot size are Almen-strip numbers, not “blast it a bit more.” Doing peen after grind or before coating is a specification choice; mixing them up is how you hide cracks or wreck a finish. Penetrant timing relative to peen is written on the traveler under quality control.

Some thermal spray procedures want a peened substrate; some want a blasted profile only. Pretending they are interchangeable is a field failure. If the part already has a coating, peening the coating is a different, usually wrong, idea unless the spec says so. Strip, inspect, then decide.

The shop on Our Company lists craftsmen and gages; peening belongs in that list even when the menu puts it with processes. From the home page it looks like a side dish. On a shaft that sees bending, it is the meal. Send the peen spec callout — intensity, coverage, shot, and masked areas. Related guns and grind sit on thermal spray.

Operators who treat peening like cleaning shot leave a pretty satin and no compressive layer worth the invoice. Strips in the lot say whether the machine was in range that morning. That is dull. Dull is the point.

Almen or it did not happen

Intensity, coverage, shot size, and masked zones belong on the RFQ. “Hit it with shot” is blast, not peen. If the part will be coated afterward, the procedure must say whether the peened layer is the bond surface or whether a separate blast is required. Doing FPI in the wrong order wastes chemistry. Aerospace fatigue callouts are not optional poetry. A pretty satin with no strip in the lot is an invoice without evidence. Fillet radius photos help fixture design. Do not peen a finished carbide land unless a spec you can show us demands it; that request usually means someone mixed two paragraphs from two manuals.