Abstract: Provided is a copper-based sliding material including a steel back-metal layer and a Cu alloy layer. The Cu alloy layer contains, by mass %, 10 to 30% of Bi, 0.5 to 5% of an inorganic compound, and the balance being Cu and inevitable impurities. The Cu alloy layer may further contain 0.5 to 5% of Sn and/or at least one element selected from the group consisting of Ni, Fe, P and Ag in a total amount of 0.1 to 10%. The inorganic compound has an average particle size of 1 to 5 ?m and a specific gravity of 70 to 130% relative to the specific gravity of Bi. Bi phase is formed in the Cu alloy layer in an average particle size of 2 to 15 ?m, and the Bi phase is dispersed in the Cu alloy layer and isotropic.

Abstract: In a copper-based sliding material in which a Cu alloy layer contains 5% to 30% by mass of Bi, and the balance consisting of Cu and an unavoidable impurity, Bi is dispersed as particles of a Bi phase in the Cu alloy layer, and the mass ratio of the particles having a particle size of 2 to 50 ?m and a circularity of 0.1 to 0.7 is 30% or more in the entire Bi phase in the Cu alloy layer, so that the particles of the Bi phase are uniformly dispersed in the Cu alloy layer. Therefore, the particles of the Bi phase in the Cu alloy layer are sequentially exposed to a sliding surface as wear of the sliding material progresses while excessive flow-out of molten Bi is prevented, so that improved seizure resistance is achieved.

Abstract: In a copper-based sliding material in which a Cu alloy layer contains 5% to 30% by mass of Bi, and the balance consisting of Cu and an unavoidable impurity, Bi is dispersed as particles of a Bi phase in the Cu alloy layer, and the mass ratio of the particles having a particle size of 2 to 50 ?m and a circularity of 0.1 to 0.7 is 30% or more in the entire Bi phase in the Cu alloy layer, so that the particles of the Bi phase are uniformly dispersed in the Cu alloy layer. Therefore, the particles of the Bi phase in the Cu alloy layer are sequentially exposed to a sliding surface as wear of the sliding material progresses while excessive flow-out of molten Bi is prevented, so that improved seizure resistance is achieved.

Abstract: Provided is a copper-based sliding material including a steel back-metal layer and a Cu alloy layer. The Cu alloy layer contains, by mass %, 10 to 30% of Bi, 0.5 to 5% of an inorganic compound, and the balance being Cu and inevitable impurities. The Cu alloy layer may further contain 0.5 to 5% of Sn and/or at least one element selected from the group consisting of Ni, Fe, P and Ag in a total amount of 0.1 to 10%. The inorganic compound has an average particle size of 1 to 5 ?m and a specific gravity of 70 to 130% relative to the specific gravity of Bi. Bi phase is formed in the Cu alloy layer in an average particle size of 2 to 15 ?m, and the Bi phase is dispersed in the Cu alloy layer and isotropic.

Abstract: A segregation preventive or eliminative operation in a continuous casting process is performed under the following conditions:The solidified/unsolidified ratio of the solidifying block is in a range of 0.5:1 to 0.9:1;The ratio between the overall compression .delta. (mm) versus thickness of the unsolidified area in the block (d mm) is greater than or equal to 0.5 or the thickness (d mm) of the unsolidified layer in the solidifying block is: ##EQU1## where D is the thickness of the block before compression. Casting speed may be controlled according to thickness of the solidifying shell at or near a crater end. Preferably, electromagnetic stirring is performed before performing compression forging.

Abstract: A steel-making process in a converter, which includes using a carbon monoxide gas as an agitating gas supplied from a position lower than molten metal bath level.

Abstract: A tuyere for blowing an agitating gas into molten steel is arranged in the bottom of an oxygen top-blown converter in order to improve the refining effect of molten steel and has a ratio of blow sectional area S (cm.sup.2) to inner peripheral length L (cm) of not more than 0.17, preferably not more than 0.125.

Abstract: Steel sheets having an excellent enamelability are produced by adjusting the carbon, silicon, manganese, aluminum, oxygen and boron contents in a molten steel to be not more than 0.020% of carbon, not more than 0.03% of silicon, not more than 0.50% of manganese, not more than 0.010% of aluminum, nor more than 0.050% of oxygen, boron within a range of 0.003-0.020% being in such an amount B(%).times.0(%) of more than 1.times.10.sup..sup.-5 and the remainder being inevitable impurities and iron, and hot rolling the resulting steel, cold rolling the steel and subjecting to a recrystallization annealing in a conventional manner.