1957 Volume 26 Issue 2 Pages 77-83
As the first step of producing high tensile structural steels (H. T. 60) with tensile strength over 60 kg/mm2 and good weldability, five laboratory heats prepared by adding Ni, Cr, Mo, V and Ti, to the Si+Mn type usually adopted for making a high tensile steel with tensile strength below 60 kg/mm2 were melted and tested. From this experiment it is deduced that by decreasing C and Mn contents and adding V and Ti, the ductility transition temperature and the maximum hardness in H. A. Z. can be lowered, keeping tensile strength above 60 kg/mm2. But the plates as rolled would be attended with the danger that elongation may not be high enough and ductility transition temperature lowered. In case of normalizing plates, however, the tensile strength will be lowered and the ductility can be considerably improved. And it is learned that replacing Mo with V and Ti, better weldability can be achieved as H. T. 60 plates.