Abstract: Provided are: steel for knives, having a higher hardness and better corrosion resistance than conventional steel for knives; a knife; steel for martensitic knives; and a production method for same. The steel for knives comprises a component composition containing, in mass %, 0.45%-1.00% C, 0.1%-1.5% Si, 0.1%-1.5% Mn, 7.5%-11.0% Cr, and 0.5%-3.0% of either Mo or W or a complex of both (Mo+W/2), with the remainder being Fe and unavoidable impurities. Also provided are steel for martensitic knives and a knife. A production method for steel for martensitic knives is also provided that includes a quenching temperature at quenching of 1,050-1,250° C., a processing temperature for subzero processing of no more than ?50° C., and a tempering temperature at tempering of 100-400° C., and obtains steel for martensitic knives that has a hardness of at least 700 HV.

Abstract: A casting green sand mold comprising at least a pair of green sand mold parts each having a cavity portion, which are stacked with their cavity portions aligned to form a metal-melt-receiving cavity; each of the green sand mold parts being formed by casting sand containing a binder and water; a hardening-resin-based coating layer being formed on at least the cavity portion of each green sand mold part; the coating layer having gas-permeable pores having sufficient permeability to permit a gas generated by pouring a metal melt to escape; and a water content in a surface layer including the coating layer in a range from the cavity surface to the depth of 5 mm being smaller than that in the inner portion of the green sand mold.

Abstract: A green sand mold comprising at least one pair of green sand mold parts each comprising a recess and a mating surface, wherein a cured layer comprising a thermosetting resin as a main component is formed on the recess and mating surface of each green sand mold part, and wherein the cured layer has hardness of 40-98, a thickness of 0.5-6 mm, and gas permeability of 70-150, is produced by applying a curing material comprising the thermosetting resin as a main component and having viscosity of 1-100 mPa·S to the recess and mating surface of each green sand mold part, combining the green sand mold parts, and then heat-hardening the curing material.

Abstract: The present invention provides a means capable of selectively introducing a disulfide bond with respect to two free thiol groups located in a molecule of an organic compound such as a peptide, or the like, in a short time by a simple treatment and also by a chemically stable method. A nitrogen-containing compound represented by Chemical Formula 1 below or a salt thereof: The symbols shown in Chemical Formula 1 are the same as defined in the specification.

Abstract: The present invention provides a means capable of selectively introducing a disulfide bond with respect to two free thiol groups located in a molecule of an organic compound such as a peptide, or the like, in a short time by a simple treatment and also by a chemically stable method. A nitrogen-containing compound represented by Chemical Formula 1 below or a salt thereof: The symbols shown in Chemical Formula 1 are the same as defined in the specification.

Abstract: A spheroidal graphite cast iron having (a) a composition comprising by mass 3.4-4% of C, 1.9-2.8% of Si, 0.02-0.06% of Mg, 0.2-1% of Mn, 0.2-2% of Cu, 0-0.1% of Sn, 0.85-3% of (Mn+Cu+10×Sn), 0.05% or less of P, and 0.02% or less of S, the balance being Fe and inevitable impurities, and (b) a duplex matrix structure comprising by area 2-40% of fine ferrite phases and 60-98% of fine pearlite phases, the maximum length of the ferrite phases being 300 ?m or less, and (c) the pearlite phases being formed around graphite particles dispersed in the duplex matrix structure.

Abstract: A method for pouring a melt using a bottom-pouring-type ladle comprising a melt-pouring nozzle and a stopper rod, comprises an opening step, in which the stopper rod is separate from the nozzle; a first closing step, in which the stopper rod moves downward, such that a lower end portion of the stopper rod comes into contact with a tapered surface of the nozzle when the horizontal distance between their center axes becomes 2 mm or more; and a second closing step, in which a lower end portion of the stopper rod further moves downward along the tapered surface of the nozzle to close the nozzle.

Abstract: A casting green sand mold comprising at least a pair of green sand mold parts each having a cavity portion, which are stacked with their cavity portions aligned to form a metal-melt-receiving cavity; each of the green sand mold parts being formed by casting sand containing a binder and water; a hardening-resin-based coating layer being formed on at least the cavity portion of each green sand mold part; the coating layer having gas-permeable pores having sufficient permeability to permit a gas generated by pouring a metal melt to escape; and a water content in a surface layer including the coating layer in a range from the cavity surface to the depth of 5 mm being smaller than that in the inner portion of the green sand mold.

Abstract: A green sand mold for producing a cast steel article, which is formed by casting sand comprising sand, a binder, and 3 parts or less by mass of a carbonaceous component per 100 parts by mass of sand, and provided with a coating layer of a thermosetting resin formed at least on a recess including a cavity for forming the cast steel article, the coating layer having average hardness (measured by a self-hardening hardness meter) of 50-95 and a thickness of 0.5-2.5 mm.

Abstract: A green sand mold comprising at least one pair of green sand mold parts each comprising a recess and a mating surface, wherein a cured layer comprising a thermosetting resin as a main component is formed on the recess and mating surface of each green sand mold part, and wherein the cured layer has hardness of 40-98, a thickness of 0.5-6 mm, and gas permeability of 70-150, is produced by applying a curing material comprising the thermosetting resin as a main component and having viscosity of 1-100 mPa·S to the recess and mating surface of each green sand mold part, combining the green sand mold parts, and then heat-hardening the curing material.

Abstract: A method for pouring a melt using a bottom-pouring-type ladle comprising a melt-pouring nozzle and a stopper rod, comprises an opening step, in which the stopper rod is separate from the nozzle; a first closing step, in which the stopper rod moves downward, such that a lower end portion of the stopper rod comes into contact with a tapered surface of the nozzle when the horizontal distance between their center axes becomes 2 mm or more; and a second closing step, in which a lower end portion of the stopper rod further moves downward along the tapered surface of the nozzle to close the nozzle.

Abstract: A spheroidal graphite cast iron having (a) a composition comprising by mass 3.4-4% of C, 1.9-2.8% of Si, 0.02-0.06% of Mg, 0.2-1% of Mn, 0.2-2% of Cu, 0-0.1% of Sn, 0.85-3% of (Mn+Cu+10×Sn), 0.05% or less of P, and 0.02% or less of S, the balance being Fe and inevitable impurities, and (b) a duplex matrix structure comprising by area 2-40% of fine ferrite phases and 60-98% of fine pearlite phases, the maximum length of the ferrite phases being 300 ?m or less, and (c) the pearlite phases being formed around graphite particles dispersed in the duplex matrix structure.