ABSTRACT
The supply chain for oil and gas extraction currently faces great challenges with regard to the machinability of stainless steels for such applications. The selection of alloys with high corrosion resistance, toughness and mechanical properties is a complex process, since the conditions under which these materials are exposed are increasingly severe, especially under deep waters. Despite the investment in the sector, the need for studies on the machinability of these alloys remains. The principal goal of this work is the study the behavior of CA6NM supermartensitic stainless steel when turning with coated carbide tools corresponding to ISO grades M10 and M10-20 coated with TiCN + Al2O3 + TiN and to grade ISO M30-40 coated with (Ti, Al) N possessing high Al content. Additionally, the influence of cutting fluid pressure (0.1 and 80 bar, respectively) and cutting speed on machined surface roughness (Ra parameter), tool life and wear mechanisms was assessed. The findings indicated that tool material, cutting fluid pressure and cutting speed did not present statistical influence on roughness. In contrast, all the investigated factors affected tool life and wear and the ISO grade M10 insert coated with TiCN + Al2O3 + TiN presented best overall performance.
Keywords
supermartensitic stainless steel; turning; coated carbide tools
