Cavitation erosion of laser processed Fe-Cr-Mn and Fe-Cr-Co alloys

Purpose: Purpose of this paper is attempt explanation how laser beam processing influence on the cavitation performance of the Fe-Cr-Mn and Fe-Cr-Co alloys. This kind of alloys are frequently used in Polish power plants to routine repairs of damaged blades working under cavitation loading. Design/methodology/approach: Padding welds of investigated alloys were tested for three cases: after laser melting, after laser heating of the solid state and without additional processing. Cw. CO2 laser was employed as a source of radiation. The rotating disk rig was used in cavitation erosion investigations. The chemical composition, microstructure, and phase identification of the processed and subjected to cavitation loading alloys were examined using light microscopy, X-ray diffractometry and scanning electron microscopy, respectively. Findings: Phase transformation for processed and unprocessed alloys was observed. Obtained results revealed that laser processing contributes to delaying of austenite → martensite phase transformation. Kinetic of this transformation is different for investigated alloys and depends on the chemical composition and applied laser processing. Research limitations/implications: Reported research ought to be completed and full cavitation curves (volume loss in time) for laser beam processed alloys must be done. Practical implications: For low intensity of cavitation loading, like in field conditions laser beam processing can increase of cavitation erosion resistance of investigated alloys due to increase of hardness. Originality/value: Confirmation that creation of the transformed and hardfacing structures by laser techniques leads in many cases to considerable changes in cavitation erosion properties of the processed materials.