Multiscale measurements of residual stress in a low alloy carbon steel weld clad with IN625 superalloy

Fatigue fracture is one of the major degradation mechanisms in 4330 low alloy carbon steel pumps utilized in the hydraulic fracturing process operating under cyclic loading conditions. A weld cladding technology has been developed to improve the resistance of these components to fatigue crack initiation, by cladding with a secondary material. This process introduces a residual stress profile into the component that can be potentially detrimental for fatigue performance. The cladding technology under examination is a 4330 low alloy carbon steel substrate weld clad with a nickel-chromium-based superalloy IN625, investigated herein using several experimental residual stress measurement techniques. Understanding the magnitude and distribution of residual stress in weld clad components is of utmost importance to accurately assess the performance of the component in service. This study summarizes the results of residual stress measurements, using X-Ray diffraction, hole drilling based on electronic speckle pattern interferometry, deep-hole drilling and the contour method, to obtain the residual stress distributions from the surface of the weld clad, through the clad layer and into the substrate material. The results of deep-hole drilling and the contour method show large scale tensile residual stress in the clad layer and compressive residual stress in the majority of the substrate. However, the X-ray diffraction and hole drilling methods indicated the presence of short scale compressive residual stress on the surface and near surface of the clad layer. It was shown that these measurement techniques are complementary in assessing the residual stress profile throughout the entire component.