PURPOSE: To eliminate defects such as blowholes on the surfaces of a steel ingot by irradiating laser rays to the surfaces of the steel ingot to remelt a fixed depth range then allowing the molten layer to freeze quickly.
CONSTITUTION: Since surface defects such as blowholes and slag inclusion exist on the surfaces of a continuously cast slab of general carbon steels or alloy steels, laser rays of high energy are irradiated and are scanned to remelt the range of 1W3mm depth from the surface where the blowholes, etc. exist. The molten layer is allowed to cool and freeze quickly, whereby the surface detects are removed. The remelting by the irradiation of the laser rays permits easy controlling of melting depth through electrical or optical controlling and since the beam diameter and scanning speed may be adjusted so that the temp. on the molten metal surface layer does not rise higher than the b.p. of that steel material, the dissipation of the steel material surface owing to evaporation and the occurrence of fuming that aggravates working environments are obviated.
YANO SHIUYA
FUJII TETSUYA
SASAKI HIROAKI
Next Patent: PRECIPITATION HARDENING METHOD OF FE3C BY HIGH-FREQUENCY HEATING