電氣熔接用高張力鋼板の試作研究

抄録

As a high-tensile steel sheet for ship-building a Mn bearing low alloy steel like DS was hitherto used, but since electric arc welding became widely applied for the purpose of saving weight and labor, high tensile steel of superior weldability has been in demand. This study was made by the Japanese Navy technical staffs during the World War II.
Eleven kinds of steel regarded as being suitable for welding were selected with reference to the Japanese and foreign technical literatures.
Thirteen kinds of steel in all including DS and HT selected for comparison with these steels were melted with a high frequency furnace and then rolled into sheets of 12mm width. The mechanical properties, weldability and strength of butt-welded joint of these experimentally manufactured steel sheets were tested. As a result of tests, it was confirmed that DS and HT hitherto used had quite inferior weldability, while Si-Mn steel showed the most excellent properties.
In view of the test results and from the standpoint of mass production and domestic natural resources, the standard of the components of steel experimetally manufactured by an O.H. furnace was determined as follows: C 0.15-0.20%, Si 0.3-0.7% and Mn 0.9-1.2%. Eight charges were melted, poured into 6-18t ingots and rolled into 12-22mm wide sheets in the Kure Naval Arsenal and Yawata Iron Works. Several types were performed on these experimentally manufactured sheets, and they showed generally satisfactory results.
Mechanical properties of these sheets were as follows: Yield point 32-43kg/mm², tensile strength 52-60kg/mm², elongation 23-32% (G.L.=200mm)
Trial use of these sheets for construction of submarines with an application of welding showed excellent results without causing any defects.