Technical comparison of fiber laser and plasma cutting processes on carbon steel and stainless steel

The thesis deals with a comparison of the most frequently used thermal cutting technologies, Fiber laser cutting and plasma arc cutting applied to stainless steel AISI 304 and carbon steel S275JR, with a focus on experimental measurement of cut quality and evaluation of characteristics of the cut surface. It gives a mutual comparison of these technologies in terms of cut quality parameters. The goal of this research work was to use the property changes in the used material (affected by fiber laser, plasma cutting) as the quality indicator of the cutting process. The influence of cutting technologies on the quality, mechanical properties and microstructure of the cut edges of the materials is presented. In this study kerf width, perpendicularity of the cut edges, surface roughness (respect to ISO 9013 standard), surface appearance of cut edge, dross formation, melting of top edge, piercing, metallographic and microhardness test of heat affected zone were investigated. The results revealed that the surface in both materials achieved by fiber laser cutting have highest roughness due to heavy striations on the surface, however, regardless of these fiber laser shows tight tolerance and high quality in other quality characteristics. It has highest perpendicularity value, lowest melting of top edge (sharp edge) and leaves very small kerf width. Therefore, it can expected that fiber laser has also the lowest piercing between two technologies. It’s worth mentioning that, both materials revealed comparable characteristics during the experiments. On the other hand, Plasma cutting performs cutting with lower surface roughness with better surface appearance, but that’s not whole story. Results revealed that plasma cutting presents lower performance in perpendicularity test, kerf width test, melting of top edge (round edge) and piercing. Moreover, Metallography and Microhardness test of mentioned materials under the thermal cutting technologies shows fiber laser has comparable HAZ in compare with plasma cutting. Totally, this study reveals that fiber laser has tight tolerance and high quality in thin plates, On the other hand fiber laser usually shows lower quality in high thickness. While, plasma cutting shows higher speed, Good balance between tolerance and quality, significant thickness range and material flexibility which is more suitable for higher thickness applications.