Abstract: A steel plate splicing facility includes, a steel plate heating apparatus for retrieving and heating a preceding steel plate and a following steel plate, and a shear-joining apparatus for clamping a tail end portion of the preceding steel plate and a leading end portion of the following steel plate in an overlapping condition by a die and a clamp and shearing them with a punch, such that surfaces of the tail end portion and the leading end portion are newly formed and brought in contact with each other in order to them. The shear-joining apparatus joins the preceding and following steel plates at a temperature equal to or higher than 350° C. and at a percentage clearance c/t equal to or lower than 5%, c/t being defined by c/t=D/(t1+t2)×100 where D represents a distance between the punch and the die, and t1 and t2 represent a thickness of respective steel plates.

Abstract: A steel plate splicing facility includes a steel plate heating apparatus for heating a preceding material and a following material, and a shear-joining apparatus for joining the preceding material and the following material. The preceding material is a steel plate currently undergoing pickling, or pickling and cold rolling, and the following material is the next steel plate to undergo pickling, or pickling and cold rolling. In the shear-joining apparatus, the preceding material and the following material are clamped in an overlapping condition by means of a die and a clamp and are sheared by means of a punch in such a manner as to bring respective newly-formed surfaces in contact with each other for joining.

Abstract: An alloying system for a galvanized steel sheet, the alloying system using an induction heating coil, wherein an impedance matching apparatus is provided between the induction heating coil and a high frequency power source. The impedance matching apparatus comprises a matching transformer having a plurality of intermediate contact points for arbitrarily selecting a turn ratio, and a switching device for alternative changeover of the intermediate contact point, whereby even when the load impedance of the steel sheet varies, maximum power source output is obtained, such that an appropriate heating temperature necessary for forming an alloy layer of the steel sheet can be supplied.

Abstract: An alloying system for a galvanized steel sheet, using an induction heating coil, wherein the temperature of the steel sheet in an induction heating furnace is measured based on the impedance of a high frequency heater, and the amount of heating is controlled by feedback, to form an alloy layer of the steel sheet.