During our certified shot peening process, each piece of shot that strikes the material acts as a tiny peening hammer, imparting to the surface a small indentation or dimple. To create the dimple, the surface of the material must yield in tension. Below the surface, the material tries to restore its original shape, thereby producing below the dimple, a hemisphere of cold-worked material highly stressed in compression.
Nearly all fatigue and stress corrosion failures originate at the surface of a part, but cracks will not initiate or propagate in a compressively stressed zone. Because the overlapping dimples from controlled shot peening create a uniform layer of compressive stress at metal surfaces, controlled shot peening services provide considerable increases in part life.
In most cases of long-term failure, the common denominator is tensile stress. Tensile stresses attempt to stretch or pull the surface apart and may eventually lead to crack initiation. Shot peening helps slow crack growth significantly in a compressive layer. Shot peening is the most economical and practical method of ensuring surface residual compressive stresses.
Compressive stresses are beneficial in increasing resistance to fatigue failures, corrosion fatigue, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and erosion caused by cavitation. The maximum compressive residual stress produced just below the surface of a part, by shot peening is at least as great as one-half the yield strength of the material being shot-peened.
While shot peening and blasting both require shooting a stream of material against the surface of a part, they do not yield the same result. While shot peening is a technique used to prolong the life of a part, shot blasting is done to clean and smooth a surface for processing.
We have several machines available for commercial shot peening services in Minneapolis, and for other businesses in the Twin Cities and greater Minnesota and Wisconsin area. We offer different sizes of shot for various applications and a certified team of experts to help you determine the best options for your metal parts.
We can provide high-volume shot peening services in Minnesota along with other metal finishing services. Minneapolis and Wisconsin-area businesses can use our dedicated team as a one-stop-shop for all of their metal finishing needs.