Metallurgical Study on the Reheat Cracking at the Weld Zone of Steel (Report 3)

Effects of the Grain Size and Structure of Steel on the Sensitivity to Reheat Cracking

Abstract

The present authors have referred to the grain size and matrix structure as the metallurgical factors having effects on the sensitivity to reheat cracking, and studied the effects of these factors on the reheat cracking.
The results of the study obtained are summarized as follows:
1) The effect of the peak temperature during the synthetic thermal cycle on the sensitivity to reheat cracking is large. The higher the peak temperature rises, the larger the sensitivity to reheat cracking becomes. It has become evident that in this instance, because the difference in the matrix hardness and 0.2% proof stress is negligibly small due to the difference in the peak temperatures, the effect of the grain size is noticeably great.
2) Although the effect of the matrix structure on the sensitivity to reheat cracking does not manifest itself prominently as much as the grain size would do. As the matrix structure becomes softer, the sensitivity to reheat cracking decrease.