Residual stress in weldments

Abstract

Undesirable residual stresses can be introduced into engineering components during welding. These stresses can affect the load carrying capacity and resistance to fracture of components. In order to quantify their effect it is necessary to know their magnitude and distribution.

Several techniques are available for measuring the residual stresses in welds. However, only neutron diffraction is capable of determining these stresses non-destructively within the interior of components. In this paper, neutron diffraction is used to obtain the residual stress profiles generated in a selection of weldments manufactured by different processes. The processes considered include linear friction, inertia, electron beam and manual metal arc welding. It is found that these welding techniques typically produce a triaxial tensile residual stress field in the weld metal which decays rapidly through the heat affected zone to produce balancing compression in the parent material.

Key Words:

• Residual stress
• Weldments
• Neutron diffraction
• Strain tensor