Análisis de la influencia del tiempo de aplicación del tratamiento termoquímico de cementado en la dureza superficial del acero AISI/SAE 1018

Abstract

An analytic study about the influence of application time of the carburizing thermochemical treatment on the surface hardness of the AISI/SAE 1018 steel is presented. This steel contains low carbon and it is usually utilized in applications where strong loads are not applied and the wear is low. This steel has a low hardness, therefore, it is thermally treated and thermochemical treatments, such as carburizing, are also applied, increasing the carbon content as well as surface hardness. Chapter I is focused on making known the characteristics of this steel with melting temperature between 1400 to 1800 °C and for heat treatments, such as carburizing or quenching, the austenitization temperature must be considered, above 750 °C, generally. The purpose of a heat treatment is to change the physical properties of a steel and achieve the required properties for a certain application. Chapter II describes the used methodology to carry out this project, as well as the different experimental procedures done. In addition, it is required to know the established standards for conducting a test, in this case, using the ASTM E18 - 19 standard for the measurement of surface hardness in a test specimen. Chapter III presents the experimental procedures for the development of the thermal treatments that were performed. The sequence of these treatments and values of parameters, such as temperatures and heating times, have been indicated to do four different carburizing heat treatments. Subsequently, quenching and tempering were carried out to increase surface hardness and relieve internal stresses. Finally, in Chapter IV, obtained results were interpreted, both experimentally through the measurement of surface hardness and the ANOVA analysis, indicating that all of them follow a normal distribution with a reliability of 95%. Personal statements and commentaries have been presented to explain the experimental procedure.