Super austenitic stainless steels are denominated as such because they present good resistance to pitting corrosion and, also, offer excellent mechanical properties, which makes them one of the options for the production of components used by the petroleum industry. However the superficial foundry hardening during the machining processes can change these properties. This paper aimed at investigating the effects of the machining operation on the surface of the super, austenitic steel ASTM A351 CN3MN. Samples of the casted steel suffered wear due to cylindrical machining, with different cutting speeds, using indexable carbide inserts of varied geometries. The analysis of the microstructure on the casting surface was accomplished by optical microscopy and the foundry hardened surface was determined by micro-hardness. The mechanical properties of the steel were determined by traction assay. The wear in the cutting inserts was accomplished in a MEV.6018388