Caracterización de la junta soldada mediante el proceso smaw de un acero astm a 516 gr 70 a nivel microestructural sometido con pwht de revenido y distensionado

Abstract

The objective of this project is to evaluate the microstructural behavior of an ASTM A 516 Gr 70 steel in a welded joint when a post-heating process is applied. Microstructural analysis and microhardness tests have been developed according to the heat treatments applied (stress relieving and tempering), in addition to the identification of the optimum post-heating temperatures in the welded joints using the SMAW welding process, in order to avoid the appearance of overheating cracks of the material in the welded joint. Therefore, it is intended to study and analyze the failure mode known as overheating cracking in the welded joint of an ASTM 516 Gr 70 steel used for the manufacture of oil pipelines, boilers and pressure tanks, characterizing the mechanical and microstructural properties after the application of welding and heat treatment, in order to obtain an efficient welding process that guarantees that this type of failure known as overheating cracking will not occur. A Welding Procedure Specification (WPS) was carried out by making a weld using the SMAW process on an ASTM 516 Gr 70 steel plate with a thickness of 3/8" and dimensions of 200 mm x 200 mm, where 3 samples of the weld were taken, one of which was left as a reference or comparison frame, The second sample was subjected to PWHT tempering at a temperature of 700°C and the third sample was subjected to PWHT stress relieving at a temperature of 600°C, identifying the change in microstructures and mechanical properties to establish the characterization of the welded joint by the SMAW process of an ASTM 516 Gr 70 steel subjected to PWHT tempering and stress relieving at the microstructural level.