Influence of the Application of Quick Thermal Welding Cycles in the Toughness of Carbon Steels Susceptible to Aging

A number of cases of brittle fracture in welded structures can be explained by an accelerated aging resulting from the use of welding thermal cycles on strain-hardened steels. This paper presents new experimental results of an investigation of this phenomenon as well as a rationale for it. Results on rimmed steels indicate that there is a critical temperature, below the A₁ transformation point, which results in the maximum loss of notch toughness. The magnitude of the embrittlement suggests that the standard test recommended for strain aging susceptibility of these steels should be modified to provide better measure of the effect. Some further practical recommendations are made about these steels.