More recently a modified stainless steels have been used to produce various structural elements that work in complex operating conditions. Stainless steel X8CrNiS18-9 (standard EN 10088-3: 2005) is the most commonly used austenitic stainless steel due to its good machinability. This steel has high mechanical and working properties thanks to a complex alloying, primarily with the elements such as chromium and nickel. The content of sulphur present in the steel from 0.15 to 0.35% improves machinability. However, while sulphur improves machinability at the same time decreases the mechanical properties particularly toughness. The addition of sulphur, which is the cheapest available additive for free machining, will impair not only the transverse strength and toughness, but also the corrosion resistance.The aim of this work is to determine the influence of microalloying with boron on the machinability, corrosion resistance and mechanical properties the mentioned steel, but alsoto determine the effect of microalloying with boron on above steel, which is already microalloyed with zirconium, tellurium, or both elements (zirconium and tellurium) due to modification of non-metallic inclusions and improvement of properties.