What is Ultrasonic Peening for Welds?


Ultrasonic peening

The Ultrasonic Peening (UP) is a cold-working surface treatment processes for fatigue life improvement of welded elements and structures. During the different stages of its development the UP process was also known as ultrasonic treatment (UT), ultrasonic impact treatment (UIT), ultrasonic impact peening (UIP). The beneficial effect of Ultrasonic Peening is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material.

Ultrasonic peening use ultrasonic tool to impact the surface of a mechanical part, generating a compressive residual stress layer and improving material mechanical properties. The process of ultrasonic peening is a fatigue improvement technique which is applied via ultrasonic and mechanical impulses to the high-stressed locations in the weld. As a result of the ultrasonic peening process, which modifies the metal weld at its very atomic level, the stress concentrations and residual stress are relieved, and the integrity and strength of the structure is increased dramatically.

Ultrasonic Peening of Welds

The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material.

The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. Traditionally, UP treatment is considered in most cases for high cycle fatigue
applications, where its effects are mostly pronounced.

Butt welds in as-welded condition (left side sample) and after application of UP (right side sample)

The Ultrasonic Peening could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The UP technology and equipment were successfully applied in different industrial projects for rehabilitation and weld repair of parts and welded elements. The areas/industries where the UP was applied successfully include: Railway and Highway Bridges, Construction Equipment, Shipbuilding, Mining, Automotive and Aerospace.

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