Abstract: A sulfur-containing free-cutting steel for machine structural use, containing, in weight percent, 0.10 to 0.55% of C, 0.05 to 1.00% of Si, 0.30 to 2.50% of Mn, not more than 0.15% of P, 0.050 to 0.350% of S, more than 0.010% but not more than 0.020% of Al, 0.015 to 0.200% of Nb, 0.0015 to 0.0150% of O, and not more than 0.02% of N, and further containing, in weight percent, at least one selected from the group consisting of 0.03 to 0.50% of V, 0.02 to 0.20% of Ti and 0.01 to 0.20% of Zr, wherein the ratio S/O of the S content to the O content is 15 to 120, and at least one selected from the group consisting of an oxide, a carbide, a nitride and a carbonitride of Nb(see FIG. 1) acts as nuclei for precipitation of MnS type inclusions.

Abstract: A high-sulfur free-cutting steel which has a chemical composition containing, in mass %, 0.03 to 0.20% C, 0.35% or less Si (including 0%), 0.30 to 2.00% Mn, 0.01 to 0.15% P, 0.35 to 0.65% S 0.0100 to 0.0250% O, 0.020% or less N, 0.005% or less Al (including 0%), 0.02 to 0.20% Nb, and further containing 0.05 to 0.50% V or 0.02 to 0.20% Ti, or both, with the remainder consisting of Fe and unavoidable impurities, wherein sulfide type inclusions, as the principal nonmetallic inclusions contained in the steel, have a mean size of 50 &mgr;m2 or less and are present at the rate of 500 to 1000 inclusions per mm2 in the cross section of the steel. The sulfur-containing free-cutting steel has a good machinability comparable or superior to that of free-cutting steels containing heavy metals which have a deleterious effect on the environment, without requiring the addition of such undesirable heavy metals.

Abstract: A sulfur-containing free-cutting steel for machine structural use, comprising, in weight percent, 0.10 to 0.55% of C, 0.05 to 1.00% of Si, 0.30 to 2.50% of Mn, not more than 0.15% of P, 0.050 to 0.350% of S, more than 0.010% but not more than 0.020% of Al, 0.015 to 0.200% of Nb, 0.0015 to 0.0150% of O, and not more than 0.02% of N, and further containing, in weight percent, at least one selected from the group consisting of 0.03 to 0.50% of V, 0.02 to 0.20% of Ti and 0.01 to 0.20% of Zr, wherein the ratio S/O of the S content to the O content is 15 to 120, and at least one selected from the group consisting of an oxide, a carbide, a nitride and a carbonitride of Nb (see FIG. 1) acts as nuclei for precipitation of an MnS type inclusions.

Abstract: A high-sulfur free-cutting steel which has a chemical composition comprising, in mass %, 0.03 to 0.20% C, 0.35% or less Si (including 0%), 0.30 to 2.00% Mn, 0.01 to 0.15% P, 0.35 to 0.65% S, 0.0100 to 0.0250% O, 0.020% or less N, 0.005% or less Al (including 0%), 0.02 to 0.20% Nb, and further containing 0.05 to 0.50% V or 0.02 to 0.20% Ti, or both, with the remainder consisting of Fe and unavoidable impurities, wherein sulfide type inclusions as principal nonmetallic inclusions contained in the steel have a mean size of 50 &mgr;m2 or less and are present at the rate of 500 to 1000 inclusions per mm2 in the cross section of the steel. The sulfur-containing free-cutting steel has a good machinability well comparable to or superior that of free-cutting steels containing heavy metals which have a deleterious effect on the environment, without requiring the addition of such undesirable heavy metals.

Abstract: The present invention provides corrosion resistance clad steels comprising a steel core and a cladding of a corrosion resistance metallic material tightly covering the circumference of the core, the interface between the core and cladding being metallurgically bonded. As the core materials, steel bars for concrete reinforcement including PC steel bars; or materials for sections (e.g., angles or channels) may be appropriately selected depending on the intended use. The foregoing steel materials is produced by a method comprising the steps of arranging the corrosion resistance metallic cladding member over the entire surface of the circumference of the steel core member and hot rolling to form an intimate metallurgical bonding at the interface between both members, thereby forming the foregoing clad steel material. The material may be formed into deformed steel bars.

Abstract: A hydraulic trench support includes a piston and cylinder head supported within a cylinder such that the cylinder head is fixed at one end of the cylinder and the piston is moveable within the cylinder. A piston rod is coupled to the hydraulic piston at one end and extends outside the cylinder and beyond at the other end. A pair of load bearing bases having generally planar construction are attached to the piston rod portion extending beyond the cylinder and to the cylinder head. Means are provided for introducing a fluid under pressure into the cylinder between the inwardly facing surfaces of the cylinder head and piston to provide an outwardly expanding force there between which is coupled to the base members to provide a sidewall retaining force. In one embodiment, spring means are provided which bias the hydraulic trench support toward a contracted position in the absence of fluid pressure.

Abstract: A method and an apparatus for continuously forming embossed sheets having good mechanical properties but no directional property. The apparatus has a pair of temperature-adjustable forming rolls, axial distance regulating devices to control the distance between the axes of the pair of forming rolls and a driving means for rotating the pair of forming rolls, each of the pair of forming rolls being provided with a plurality of ring-shaped blocks having a large number of projections on their circumferential surfaces; and the method comprises the steps of: introducing a sheet into a space between the pair of forming rolls, bringing the sheet into contact with the projections of the forming rolls, where the projections of the pair of forming rolls engage with one another without pressed contact, thereby making the sheet undergo plastic deformation and forming a large number of projections on both sides of the sheet.

Abstract: A leaded, free-cutting steel is manufactured by a continuous casting process without causing any pollution of the environment or manufacturing apparatus by toxic gases or fumes and in a high yield of lead addition with a high quality, wherein lead, lead alloy, or a composite lead feed material comprising lead or lead alloy covered with a metallic material harmless for the steel such as, for example, aluminum or iron, is directly added to molten steel which is being electromagnetically stirred in the horizontal direction in a mold.