A STUDY OF CLEAVAGE FIBROUS TRANSITION-TEMPERATURE OF 15MNVN STEEL WELD METAL

Three weld metals containing Mn, Mo and Ni and one containing Mn and M o were obtained using the submerged arc welding process. Cleavage/fibr ous transition temperatures of the weld metals were determined based o n crack opening displacement (COD) vs., temperature curves and fractur e surface examination. Three main factors affecting cleavage/fibrous t ransition temperature of the weld metals, i.e., cleavage strength, yie ld stress and stress intensification of specimens with a crack, were i nvestigated. The cleavage strength was found to be influenced by the a verage area of M-A constituents. There is almost no difference in the yield stress for all four weld metals. Lower stress intensification ha s been achieved for the weld metals containing Mn, Mo and Ni as compar ed with that containing Mn and Mo. As a result, the transition tempera tures of the weld metals containing up to 0.36% of nickel are signific antly lower than that of the Mn-Mo weld metal. An attempt was made to predict the transition temperatures, and the prediction is in agreemen t with the experimental results.