Dr. V. Prieb
Reduction of internal stresses in metallic workpieces
by ultrasonic treatment
Dr. V. Prieb
"MFS-Büro Dr. Prieb", Berlin, 2001
(on behalf of IHK Bremen)
Abstract: Based on the analysis of theoretical and experimental data, an ultrasonic method is proposed
as a treatment method for the removal of internal mechanical stresses (residual stresses) in metallic
workpieces instead of traditional and elaborate annealing process. The ultrasonic treatment includes
both the traditional action mechanisms for reducing of internal stress and ultrasound-specific effects.
Technical aspects and requirements for generators and ultrasonic vibration systems are also considered.
Each manufacturing and processing of metallic workpieces produces in them the internal stresses,
which balance each other within the volume of the workpiece, remain totally or partially retained after the end
of the technological process, and are therefore also referred to as residual internal stresses or residual stresses.
The remaining internal stresses are elastic in nature, ie they are below the yield.
These macroscopic residual stresses (so-called stresses of the first order) arise as a result of uneven plastic deformation
or an unequal change in the specific volume in different areas of the metal body. The residual stresses affect the
behavior of a metallic workpiece in its processing, use, and even storage. They can cause a change in shape
(distortion), an unacceptable change in the size or sometimes even the destruction of a workpiece (eg castings of aluminum alloys).
A distortion due to bending or torsional deformation takes place in a cutting shaping
(cutting, turning, milling, etc.) of a metallic workpiece, wherein the balance is upset by residual internal stresses in the volume.
"Ultrasonic treatment of metallic workpieces and equipment parts" - collected articles (pdf-file)