Method for production of composite rolled products indicating core location

A core material such as a B-Al alloy for fuel plates is embedded into a square window disposed at the center portion of a cladding plate made of a material such as Al, having a radiation transmittivity substantially equal to that of the core. A labelling material such as an U-Al alloy is embedded into a number of holes drilled into the cladding plate or the core and then a filler is charged into the holes to cover the labelling material. The thus assembled core is enclosed in an Al plate and then hot-rolled with use of a press. Since the radiation transmittivity of the labelling material is different from that of the cladding and core, the location of the core on the rolled sheet can easily be detected by external X-ray irradiation. (Ohno, Y.)