Previsão das propriedades micro estruturais e transformações de fases em o processo da temperabilidade do aço SAE 1045 através da simulação numérica computacional e verificação mediante o teste do Jominy

Abstract

This work presents the development of a project for the prediction of microstructural properties and phase transformations in the hardenability process of ASM 1045 Steel. The developed procedure mixes numerical simulation, advanced through a computational routine carried out in free code and an experimental analysis, to verify the results. The mathematical model applies concepts of numerical methods, heat transfer, phase transformation and TTT diagrams, to simulate the Hardenability phenomenon as a function of the cooling rate, including the addition of heat due to the phase change. For the experimental stage, the design and construction of an automated and instrumented Jominy test machine was developed, which aims to be a contribution tool to reinforce the study of alloy steels, in addition to obtaining cooling curves through tests with bodies standardized SAE 1045 steel test samples; The equipment was built to perform tempering tests on samples governed by ASTM A255 2002; where its function is to characterize the hardenability of steels. First, the equipment structure was built using a structural angle and ASTM A-36 steel sheet, which created a rigid structure to support other elements of the equipment. The equipment has a fast clamping and transport device between the oven and the cooling system, which has a sample fixation and centralization element that guarantees correct vertical positioning in the water outlet hole, so that cooling occurs exclusively in the lower sample base; It was essential to find the most appropriate way to adapt the oven, the transport device and the refrigeration device, also facilitating their operation. Aiming to obtain different cooling rates throughout the specimen, instrumentation with specific characteristics was designed to meet temperature monitoring. After cooling, the specimen was subjected to hardness, microhardness and metallography tests to characterize the microstructures obtained and the variation in mechanical properties for different cooling rates; in this way, it is possible to obtain analysis and hardenability results to compare with numerical simulation data.