Shot peening is a cold working process in precision engineering industry in which small spherical media called “shot” bombard the surface of a part. During the 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 pressure. Below the surface, the material tries to restore its original shape, thereby producing below the hollow dimple, a hemisphere of cold-worked material highly strained 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 shot Peening create a uniform layer of compressive stress at metal surfaces, shot peening provides considerable increases in part life. Compressive stresses are beneficial in increasing resistance to fatigue failures, corrosion fatigue, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and erosion caused by cavitations. 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.
Peening is useful in a number of precision engineering services such as it can stimulate the aerodynamic curvature in metallic wing skins used in advanced aircraft designs. Additional applications for shot peening include work hardening through cold work to improve wear characteristics, closing of porosity, improving resistance to inter granular corrosion, straightening of distorted parts, surface texturing and testing the bond strength of coatings. Precision engineering company especially metal improvement specialists can better cope up with the requirements of peening industry.
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 shot Peening create a uniform layer of compressive stress at metal surfaces, shot peening provides considerable increases in part life. Compressive stresses are beneficial in increasing resistance to fatigue failures, corrosion fatigue, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and erosion caused by cavitations. 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.
Peening is useful in a number of precision engineering services such as it can stimulate the aerodynamic curvature in metallic wing skins used in advanced aircraft designs. Additional applications for shot peening include work hardening through cold work to improve wear characteristics, closing of porosity, improving resistance to inter granular corrosion, straightening of distorted parts, surface texturing and testing the bond strength of coatings. Precision engineering company especially metal improvement specialists can better cope up with the requirements of peening industry.
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