Diseño de un proceso térmico para la mejora mecánica de tubos industriales de acero

Abstract

The present study aims to design and evaluate a heat treatment process applied to welded galvanized steel tubes to improve their mechanical reliability and reduce the occurrence of failures during a subsequent drawing process. The working hypothesis states that a subcritical stress-relief heat treatment enables a more homogenous mechanical response by attenuating the previous history of plastic deformation and work hardening, particularly in critical regions such as the weld seam and the heat-affected zone. The experimental development was carried by applying different heat treatment conditions within a temperature range between 275 °C and 325 °C and varying holding times, using controlled heating furnace. The material response was assessed through metallographic and mechanical testing, complemented by statistical analysis and predictive estimation models. The results demonstrated that the heat treatment effectively reduced microstructural gradients and improved mechanical homogeneity throughout the tube, significantly decreasing the likelihood of failure during the drawing operation. It is therefore concluded that the heat treatment condition of 300 °C for 30 minutes provides the most favorable balance between strength and ductility, being technically, statistically and economically suitable for industrial implementation. Keywords: Residual stress relief; Strain hardening; Ductility; Microstructural homogeneity.