peening , also: peining

Shot peening is a crucial process in spring making.

Shot peening may be used to further work-harden and finish the surface.

Shot peening may be used for cosmetic effect.

Shot peening is the repeated striking of a metal surface by hard shot particles.

Improper peening of the base metal surface.

The first patent for shot peening was also taken out in Germany in 1934, but was never commercially implemented.

Shot peening is a cold working process used to produce a compressive residual stress layer and modify mechanical properties of metals.

Hand peening may be performed using a peening hammer.

John Almen noticed that shot peening made the side of the sheet metal that was exposed begin to bend and stretch.

Peening is normally a cold work process (laser peening being a notable exception).

Shot peening was independently invented in Germany and the United States in the late 1920s and early 1930s.

"Procedures for Using Standard Shot Peening Almen Strip".

Though the process of peening has become rarer in metal fabrication, the ball-peen hammer remains useful for many tasks, such as striking punches and chisels.

Ultrasonic Impact Treatment versus Ultrasonic Peening.

As this peening is done with a bench-mounted rotary tool, rather than hammering, it is referred to as "rivet spinning".

Shot peening is often called for in aircraft repairs to relieve tensile stresses built up in the grinding process and replace them with beneficial compressive stresses.

Other methods include ultrasonic peening, wet peening, and laser peening (which does not use media).

Fuchs had been working with John Almen on new applications for shot peening of automobiles and military equipment companies produced before and during World War II.

Since corrosion-fatigue cracks initiate at a metal's surface, surface treatments like plating, cladding, nitriding and shot peening were found to improve the materials' resistance to this phenomenon.

In aftermarket high performance valve spring applications, the need for controlled and multi-step shot peening is a requirement to withstand extreme surface stresses that sometimes exceeds material specifications.

Laser peening is often used to improve the fatigue resistance of highly stressed critical turbine engine components, and the laser (or component) is typically manipulated by an industrial robot.

Hand peening may also be performed after welding to help relieve the tensile stresses that develop on cooling in the welded metal (as well as the surrounding base metal).

Shot peening is used on gear parts, cams and camshafts, clutch springs, coil springs, connecting rods, crankshafts, gearwheels, leaf and suspension springs, rock drills, and turbine blades.

In 2006 NASA worked with the company, and they together presented a study called: "Effects of Laser Peening, and Shot Peening on Friction Stir Welding".