Transient stress of steel phase transformation and transformation-induced fatigue

Expansion changes the size of any machine element and can thus generate severe stress or distortion failures during its operation if this phenomenon is not taken into account during the design process. On the other hand, most steels contract during heating within a short temperature range as a result of microstructural phase transformations. This transient contraction may generate further short- and long-term dysfunction of a metallic structure. The current paper focuses on this issue: investigating the effects of the microstructural transformation on the transient stress response of a metallic structure. Analysis is carried out by means of finite element simulation employing material data from typical constructional steel. The paper emphasizes the necessity of considering material phase changes when dealing with the transient stress or displacement response of a metallic structure and demonstrates the differences obtained when the transformation effects are ignored or accounted for in the design process. The mechanism of transformation-induced fatigue is thus discussed and proposed to the engineering community for establishment. (C) 2010 Elsevier Ltd. All rights reserved.