METHOD FOR MANUFACTURING GLASS BLANK FOR MAGNETIC DISK, METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK, GLASS BLANK FOR MAGNETIC DISK, GLASS SUBSTRATE FOR MAGNETIC DISK, AND MAGNETIC DISK

摘要

Provided are a method for manufacturing by press forming a glass blank for a magnetic disk that yields a glass blank for a magnetic disk having excellent surface undulation and a method for manufacturing a glass substrate for a magnetic disk. This manufacturing method for a glass blank for a magnetic disk includes a forming step that press forms a molten glass block using a pair of metal molds. In this press forming step, press forming is carried out using an isothermal heating means that reduces the temperature differences within the press forming surfaces of the metal molds during the pressing of the molten glass.