Abstract: A sintered vitrified superfinishing grindstone is provided which is a sintered product which is obtained by compression molding of a mixed powder of: a sinterable vitrified binder composed of a powder of a borosilicate glass composition; hard abrasive grains; and soft abrasive grains; and which includes bonded portions formed by necking due to heat compression, between particles of the powder of the borosilicate glass composition which are in contact with each other; and wherein the sinterable vitrified binder contains from 94 to 100% by mass of a powder composed of a low-melting-point borosilicate glass composition containing from 35 to 55% by mole of SiO2; from 3 to 5% by mole of Al2O3; from 10 to 35% by mole of B2O3; and from 25 to 30% by mole of R2O+RO.

Abstract: A sintered vitrified superfinishing grindstone is provided which is a sintered product which is obtained by compression molding of a mixed powder of: a sinterable vitrified binder composed of a powder of a borosilicate glass composition; hard abrasive grains; and soft abrasive grains; and which includes bonded portions formed by necking due to heat compression, between particles of the powder of the borosilicate glass composition which are in contact with each other; and wherein the sinterable vitrified binder contains from 94 to 100% by mass of a powder composed of a low-melting-point borosilicate glass composition containing from 35 to 55% by mole of SiO2; from 3 to 5% by mole of A12O3; from 10 to 35% by mole of B2O3; and from 25 to 30% by mole of R2O+RO.

Abstract: A master substrate 15 having a plurality of substrate areas A arranged in a matrix shape is prepared, and a piezoelectric oscillation element 5 is carried in each of the substrate areas A. A main cover 16 made of a metal having a plurality of cover areas B having a one-to-one correspondence with the substrate areas A is placed and joined on the master substrate 15. The main cover 16 is together cut along the outer periphery B? of each of the cover areas B, to simultaneously obtain a plurality of electronic devices. The productivity can be improved by simplifying the assembling steps.

Abstract: A master substrate 15 having a plurality of substrate areas A arranged in a matrix shape is prepared, and a piezoelectric oscillation element 5 is carried in each of the substrate areas A. A main cover 16 made of a metal having a plurality of cover areas B having a one-to-one correspondence with the substrate areas A is placed and joined on the master substrate 15. The main cover 16 is together cut along the outer periphery B? of each of the cover areas B, to simultaneously obtain a plurality of electronic devices. The productivity can be improved by simplifying the assembling steps.

Abstract: A steel resistant to intergranular stress corrosion cracking having the composition: C up to 0.20%, Si 0.05 - 0.80%, Mn 0.30 - 1.50%, P up to 0.03%, S up to 0.03%, Al (sol. Al) 0.05 - 0.25%, Zr 0.03 - 0.20%, the balance being iron and unavoidable impurities. Another intergranular stress corrosion cracking resisting steel is disclosed which contains one or both of 0.10 - 0.30% Cr and 0.10 - 0.50% Ni in addition to the composition of the first-mentioned steel.