Análise da resistência a corrosão em aços ferramenta

Abstract

Tool steels have great importance in the mechanical industry, varying their applications from matrices, molds and drills to more complex equipments. These steels are usually used in situations and environments of extreme solicitation such as cutting tools, requiring high resistance to deformation and temperature. Two samples of tool steel, one P20 modified and another steel in development, both produced by the company Villares Metals de Sumaré/SP, with the nomenclature of VP20TS and Hardmax 500 respectively, were subjected to eletrochemical corrosion tests according to potentiodynamic polarization curves, potential curves versus time and hardness tests (before and after corrosion), with the purpose of comparing the corrosion resistance between them. For the tests in which the curves were raised, using potentiostat, the duration of 1800 seconds was stipulated, with a scanning speed of 1mV.s-1, in corrosive environment (electrolyte) of NaCl 3,5%, aerated. The area subjected to the corrosive tests and the electrolyte were standardized in 0.283 cm2 (6mm diameter) and 105ml. The results obtained show that the VP20TS Steel has better corrosion resistance, with a lower current density compared to the Hardmax 500, observed by the corrosion current (Icorr) being 6.67 μA against 8.61 μA respectively, in relation to the susceptibility of steels to corrode, characteristic defined by the corrosion potential (ICorr), both showed very close values indicating similar behavior in this item.