Metallurgical modifications and residual stress in welded steel with average carbon content

• Published in: Welding International Vol. 29; no. 2; pp. 124 - 130
• Main Authors: Missori, S., Costanza, G., Sili, A., Tata, M.E.
• Format: Journal Article Trade Publication Article
• Language: English
• Published: Cambridge Taylor & Francis 01.02.2015; Taylor & Francis Ltd
• Subjects: Brittleness; Carbon content; carbon steels; cold cracking; cooling rate; Crack propagation; Failure; Formations; Fracture mechanics; hardness; hardness tests; heat-affected zone, martensite, mathematical models; measurement; mechanical properties; mechanical tests; metallography; Metallurgy; Microstructure; MMA welding; Residual stress; residual stresses; stimulating; Tensile strength; transformation; weldability
• ISSN: 0950-7116; 1754-2138
• DOI: 10.1080/09507116.2012.753310

Welded joints of metallic materials are subject to residual stress and metallurgical transformations, in particular in the thermally affected zone (TAZ), with the possible formation, especially in steels with a high carbon content, of brittle structures and a loss of tenacity. The loss of tenacity in the TAZ facilitates the formation of cracks and possible brittle fracturing or failure, following the progressive propagation of the cracked zone. Moreover, residual stresses may cause premature failure in structural elements as they have an influence on the conditions of collapse, for example on account of instability of the compressed members. In this work, the order of magnitude of residual stress is estimated for a specific case, identifying by means of an empirical-experimental approach, the portion of material more susceptible to the formation of cold cracks under the combined effect of residual stress and brittleness of the microstructure.