J. F. Cau, Johnson & Johnson Industrial, São José dos Campos, Brazil; C. Moura Neto, Instituto Tecnologico de Aeronautica, S. J. dos Campos, Brazil
Summary: The purpose of this work is explore the use of steel SAE 4340 in special applications and to study the effectiveness of titanium nitride deposition in relation to the increase in fatigue life of this steel, under three conditions: annealed, quenched / tempered, and quenched / tempered with titanium nitride (TiN) coating.