Abstract: A process for smelting steel for ultrafine carborundum sawing wires, comprising: 1) in a vacuum induction furnace, using pure iron and low-phosphorus pig iron as raw materials to be melted into molten steel under the protection of argon; vacuumizing and smelting, and degassing; using silicon iron as a deoxidizer to adjust components of the molten steel; and casting a circular ingot in vacuum; 2) cleaning the surface of the circular ingot to produce an electrode bar; 3) remelting and smelting the electrode bar as raw material to a cylindrical electroslag ingot in an electroslag furnace, wherein the electroslag protecting slag comprises: CaF2: 45-55%, Al2O3: 15-25%, SiO2: 20-25%, Na2O: 2-4%, and K2O: 1-2%; 4) forging the electroslag ingot to a square billet; and 5) rolling the forged billet to a steel wire rod, and the steel wire rod comprising [C]: 0.92-1.1%, [Si]: 0.3-0.4%, [Mn]: 0.5-0.8%, [Al]<0.0008%, [N]<0.005%, [S]<0.01%, and [P]<0.015%.

Abstract: Disclosed is a steel for an alloy structure, the chemical elements of the steel being, in percentage by mass: 0.35-0.45% of C, 0.27-0.35% of Si, 0.6-0.8% of Mn, 0.015-0.05% of Al, 0.06-0.1% of V, 0.2-1.0% of Zr, 0.001-0.005% of Mg, 0.025% or less of P, 0.015% or less of S, 0.005% or less of N, 0.001% or less of 0, the balance being Fe and other inevitable impurities. In addition, also disclosed is a manufacturing method for the steel for an alloy structure, the method comprising steps of: (1) smelting, refining, and casting; (2) blooming and cogging; (3) secondary hot rolling to form a product; and (4) heat treatment including quenching and tempering. The steel for an alloy structure is designed by adding trace alloy elements, the steel for an alloy structure is further strengthened and toughened, and the manufacturing cost is low.

Abstract: Disclosed are a continuous-curvature convex roll for continuously casting a bloom, and a manufacturing method therefore. An outer contour curve of a working portion of a body of the continuous-curvature convex roll contains a first straight-line segment (AB), a first transition curve segment (BC), an intermediate straight-line segment (CD), a second transition curve segment (DE) and a second straight-line segment (EF). The BC, the AB, and the CD have continuous first-order derivatives, continuous second-order derivatives, and continuous curvatures, thus forming a first transition curve with a continuous curvature. The BC and the DE are mirror-symmetrical. The continuous-curvature convex roll can uniformly deform a blank cast in a deformation area, thereby reducing cracks. The transition curve of the convex roll can be reduced, thereby being capable of further reducing a rolling pressure and the withdrawal resistance.

Abstract: Disclosed is a light reduction method for continuous casting of a bloom plain-barrelled roll-roll combination. The method comprises: firstly obtaining three-dimensional temperature field profile, a two-phase region, solid-phase region thickness, and solid-phase fraction of a billet, determining positions of start and end rolls of the reduction, and setting a reduction amount of each tensioner roll according to the volume shrinkage of the billet; in an interval fs=0.9-1.0 of the solid-phase fraction of the billet, performing a heavy reduction working mode; and in an interval fs=0.25-0.80 of the solid-phase fraction of the billet, performing a light reduction working mode.

Abstract: Disclosed is a light reduction method for continuous casting of a bloom plain-barrelled roll-roll combination. The method comprises: firstly obtaining three-dimensional temperature field profile, a two-phase region, solid-phase region thickness, and solid-phase fraction of a billet, determining positions of start and end rolls of the reduction, and setting a reduction amount of each tensioner roll according to the volume shrinkage of the billet; in an interval fs=0.9-1.0 of the solid-phase fraction of the billet, performing a heavy reduction working mode; and in an interval fs=0.25-0.80 of the solid-phase fraction of the billet, performing a light reduction working mode.

Abstract: Disclosed are a continuous-curvature convex roll for continuously casting a bloom, and a manufacturing method therefore, belonging to the field of metal casting. An outer contour curve of a working portion of a body of the continuous-curvature convex roll consists of a first straight-line segment (AB), a first transition curve segment (BC), a intermediate straight-line segment (CD), a second transition curve segment (DE) and a second straight-line segment (EF). The first transition curve segment (BC), the first straight-line segment (AB), and the intermediate straight-line segment (CD) have continuous first-order derivatives, continuous second-order derivatives, and continuous curvatures, thus forming a first transition curve with a continuous curvature. The first transition curve segment (BC) and the second transition curve segment (DE) are mirror-symmetrical.

Abstract: A spring steel having a superior fatigue life, and a manufacturing method for the same. The chemical components thereof are as follows in weight percentage: C: 0.52-0.62%, Si: 1.20-1.45%, Mn: 0.25-0.75%, Cr: 0.30-0.80%, V: 0.01-0.15%, Nb: 0.001-0.05%, N: 0.001-0.009%, O: 0.0005-0.0040%, P: ?0.015%, S: ?0.015%, and Al: ?0.0045%, with the remainder being Fe and incidental impurities, wherein the following condition is also met 0.02?(2Nb+V)/(20N+C)?0.40. The spring steel of the present invention has a microstructure of tempered troostite+tempered sorbite, a prior austenite grain size less than 80 um, a size of alloy nitride and carbide precipitates being 5-60 nm, and a maximum width of single-grain inclusions being less than 30 pm. The spring steel has a handling strength greater than 2020 MPa, superior ductility and toughness (the reduction of area?40%), and a fatigue life?800,000 times, thereby meeting application requirements of high-stress springs in industries, such as automobiles, machinery, and the like.