PURPOSE: To increase the mechanical property of a weld zone and to improve the operability as well by performing butt welding by using high energy density heat source after adding a mineral oil along the butt line of a sheared steel sheet.
CONSTITUTION: The high energy density welding of a plasma welding, for instance, is performed by adding a mineral oil along the butt line immediately after the shearing of a steel plate. There is no limitation in the adding quantity of the mineral oil, but a degreasing state is necessary if it is too mush and it is preferable to restrain to the degrees of 30W50mg/m2. The vegetable and animal oils of a beef tallow and rapeseed oil, etc. are not suitable. By welding with said method the mechanical property of the weld zone can be increased because of the oxidation being prevented with the mineral oil protecting the butt part with its cracking into carbon and hydrogen.
NISHIYAMA SADAYUKI
FUKUMOTO YOSHIHARU
MINAMIDA KATSUHIRO
Next Patent: WELDING METHOD FOR SILICON STEEL STRIP BY YAG LASER