Análisis metalográfico de microdureza en una unión soldada de acero inoxidable martensítico AISI 420 y acero AISI/SAE 4340 con diferentes postratamientos térmicos

Abstract

In this project, a study of the changes and behaviors that occur at microstructural level was carried out by welding two dissimilar steels AISI/SAE 4340 and martensitic stainless steel 420 with filler electrode E309L-16, and subjecting them to different cooling thermal post-treatments. The problem to be solved in this monograph is to analyze the microstructural changes that occur in the heat-affected zone due to welding, after applying the thermal post-treatments, this process is widely used in the industry and presents failures due to the change in temperature in relation to the base materials. For this purpose, a series of specific objectives were proposed, among which are, to make welded samples of the materials and take them to a maximum temperature between 800 to 1000 (°C), then subject them to cooling with water, oil and room temperature, in order to identify the phases that are generated in the areas adjacent to the joint affected by the ZAC heat, and by means of a microhardness test to determine the resistance given the thermal post-treatment. The present paper took as references studies carried out on the microstructural transformation in dissimilar welds of austenitic stainless steel with ferritic stainless steel and weldability in stainless steels and dissimilar steels. It is expected to obtain three samples with heterogeneous microstructural properties due to the different post-treatments, and a change in the microhardness in each of the samples in relation to the base material.