X-ray investigation of a heterogeneous steel weld

The welding process has a significant impact on the chemical composition, structure and mechanical properties of materials in heat-affected zones. The existing approaches to the diagnostics cannot predict the properties of the welded joint nor do they guarantee its reliable performance throughout the projected service life. This becomes especially relevant when investigating the welds from heterogeneous steels applied in power engineering. The main goal of this paper is to offer modern approaches to the complex technical diagnostics of steam pipelines using X-ray investigation of heterogeneous weld structures. In this work, the following research methods were used: X-ray fluorescence analysis, X-ray diffraction method, and microhardness measurement. The object of the investigation is the composite weld of 12Cr18Ni9Ti austenitic steel and 12Cr1MoV pearlitic steel. The results of this investigation show that the properties of the weldable steel changed significantly as compared to its original state. The weld structure was represented by the internal structural stress gradients despite the application of the stress relief heat treatment. The proposed approaches to the study of steel welds can be used for selecting the rational mode of post-weld heat treatment. Combined with traditional inspection methods (visual or ultrasonic inspection, etc.), these approaches can serve as a basis for technical diagnostics and the selection of constructional materials.