AVALIAÇÃO DAS PROPRIEDADES MECÂNICAS E METALÚRGICAS DO AÇO 4130H SOB DIFERENTES CONDIÇÕES DE TRATAMENTO TÉRMICO

The study analyzed the most suitable heat treatment between air cooling quen- ching and water cooling quenching, using experimental methods to support the choice, with 4130H steel as the base material. The research was conducted through mecha- nical hardness tests and metallographic analysis to evaluate the microstructural changes and mechanical properties resulting from each heat treatment. Hardness was measured using the Rockwell method, while metallographic analysis allowed for the observation of phase transformations in the treated samples. The results showed that water quenching significantly increases hardness due to the formation of martensite, but with a higher risk of residual stresses and cracking. On the other hand, air quenching resulted in moderate hardness, but with a more homogeneous microstructure and lower susceptibility to defects. Based on the comparative analysis of the mechanical properties, it is concluded that the choice of heat treatment should consider the final application of the part: for applications requiring maximum hardness and wear resistance, water quenching is recommended.