| 摘要 |
PURPOSE:To obtain a stainless steel container on which an identification number can be marked clearly. CONSTITUTION:An identification number (control number) N is marked directly to the surface 2a of a stainless steel container (a beer barrel) 1 by means of shedding laser beams. The surface of the beer barrel 1 is locally heated by energy of the laser beams. As the identification number N is marked on the heated spot when the heated spot is melted instantaneously, the container 1 does not deform on occasion of marking the identification number. As film is formed on heating and melting made locally by shedding of the laser beams by oxidation of ingredients (iron oxide, chromium oxide, etc.) included in the stainless steel, black marks are left to the part irradiated with the laser beams, and the identification number N can be marked clearly with sharp contrast made between the part irradiated and the part not irradiated with the laser beams. The identification number N is hard to be erased even though the stainless steel container is used for a long period of time. |
