| 摘要 |
PURPOSE:To produce a die having excellent surface accuracy and roughness of the die surface without requiring cold polishing in the stage of producing the die for press molding of a glass lens by forming the die of a specifically composed 13 Cr stainless steel and subjecting the die to a subzero treatment. CONSTITUTION:A die for molding a glass lens is produced of a 13 Cr stainless steel which contains about 1.6% Si, Mn or Si, Mn and Mo and is refined by an electroslag treatment or vacuum melting treatment. Such die is further hardened for abour 30 minutes in a vacuum furnace kept at 1,050 deg.C and thereafter the die is immersed for 30min in liquid nitrogen kept at -165--170 deg.C and is quickly cooled as a subzero treatment; further the die is tempered for one hour in an oil bath kept at 570 deg.C and is subjected to the 2nd subzero treatment under the conditions similar to the preveious conditions. The die is finally tempered for one hour in an oil bath kept at 570 deg.C. The die for molding the glass lens having excellent surface accuracy and surface roughness is obtd. |
