Cutting method influence on the fatigue resistance of ultra-high-strength steel

In this work, the influence of the cutting method on ultra-high-strength (UHS) steels and work hardened austenite stainless steel with regard to static and fatigue stress conditions was studied. In the experimental tests, tensile test bars and fatigue test bars were made using milling and two-laser cutting (CO2 and Yb:YAG) as well as water jet cutting. The following examinations were performed and related results reported: cutting, measurement of surface roughness, hardness test, micro-structure analyses and the measurement of the heat-effect zone. Specimen strength was tested using a standard tensile test and a fatigue resistance under reversed bending stress test. In the bending fatigue test lowest values were found in the laser cut samples, whereas milled edges gave clearly the best values.