Free-cutting steel that has the same or better machinability compared to low-carbon sulfur-lead composite free-cutting steel, despite of no-addition of Pb, is provided. Free-cutting steel contains, in mass %, C: 0.08% or less, Mn: 0.50 to 1.50%, P: 0.100% or less, S: 0.250 to 0.500%, N: 0.0050 to 0.0150%, O: more than 0.0100% and 0.0500% or less, Cr: 0.50 to 1.50%, at least one of Si, Al, or Ti: 0.050 to 0.500% in total, with the balance being Fe and inevitable impurities, with an A value defined by formula (1) satisfying 0.40 to 2.00, and with a B value defined by formula (2) satisfying 1.10×10.sup.−3 to 1.50×10.sup.−2; and a steel microstructure with distributed 3000 or more sulfide particles with an equivalent circular diameter of 5 μm or less per mm.sup.2.

A method of redistributing the binder phase of a cemented carbide mining insert having a WC hard-phase component, optionally one or more further hard-phase components and a binder includes the steps of providing a green cemented carbide mining insert; applying at least one binder puller selected from a metal oxide or a metal carbonate to only at least one local area of the surface of the green cemented carbide insert; sintering the green carbide mining insert to form a sintered cemented carbide insert; and subjecting the sintered cemented carbide insert to dry tumbling process executed at an elevated temperature of or above 100° C., preferably at a temperature of or above 200° C., more preferably at a temperature of between 200° C. and 450° C.

A helicoid conveyor screw manufactured from alloy steel and tempered by electromagnetic induction or flame used to convey abrasive granular products in the process of screw rotation under high friction and wear. Its inventive principle is related to the method for obtaining it by alloying steel with the chemical element Boron (B) and heat treating it, which results in greater hardness and durability of the flight.

A helicoid conveyor screw manufactured from alloy steel and tempered by electromagnetic induction or flame used to convey abrasive granular products in the process of screw rotation under high friction and wear. Its inventive principle is related to the method for obtaining it by alloying steel with the chemical element Boron (B) and heat treating it, which results in greater hardness and durability of the flight.

Disclosed are a drill bit for drilling and a method for manufacturing same, in which the hardness of a body part of a shank can be selectively improved by performing rapid cooling in a forced cooling method after performing rapid heating selectively only on the body part of the shank in a high-frequency induction heating method after completing infiltration.

Disclosed are a drill bit for drilling and a method for manufacturing same, in which the hardness of a body part of a shank can be selectively improved by performing rapid cooling in a forced cooling method after performing rapid heating selectively only on the body part of the shank in a high-frequency induction heating method after completing infiltration.

A cutting blade (100) adapted to be carried by a tool holder (20) provided in a robotic work tool (10), the cutting blade (100) comprising a blade body (110) and a cutting edge (120, 121) extending along at least a portion of the periphery (111) of the blade body (110), and a slit (113) arranged to receive a pin (30) for attaching the cutting blade (100) to said tool holder (20), wherein the cutting blade (100) is movable such that the pin (30) may be displaced within the slit (113). The hardness of the cutting blade (100) decreases in direction from the cutting edge (120, 121) towards the center (125) of the blade body (110) such that the hardness of the cutting edge (120, 121) is higher than the hardness of at least a center portion (126) of the blade body (110). The present disclosure also relates to a method for manufacturing a cutting blade.

Steel for machine structure use excellent in tool lifetime in a broad range of cutting speeds regardless of continuous machining, intermittent machining, or other systems and further in various machining environments such as use of a cutting fluid or a dry, semidry, and oxygen enriched environment, having a chemical composition containing, by mass %, C: 0.01 to 1.2%, Si: 0.005 to 3.0%, Mn: 0.05 to 3.0%, P: 0.0001 to 0.2%, S: 0.0001 to 0.35%, N: 0.0005 to 0.035%, and Al: 0.05 to 1.0%, satisfying [Al %]−(27/14)×[N %]≧0.05%, and having a balance of Fe and unavoidable impurities and forming an Al.sub.2O.sub.3 coating on the surface of a cutting tool by machining using a cutting tool coated on the surface contacting the machined material by metal oxides with a value of a standard free energy of formation at 1300° C. of that value of Al.sub.2O.sub.3 or more, and a machining method of the same.

Steel for machine structure use excellent in tool lifetime in a broad range of cutting speeds regardless of continuous machining, intermittent machining, or other systems and further in various machining environments such as use of a cutting fluid or a dry, semidry, and oxygen enriched environment, having a chemical composition containing, by mass %, C: 0.01 to 1.2%, Si: 0.005 to 3.0%, Mn: 0.05 to 3.0%, P: 0.0001 to 0.2%, S: 0.0001 to 0.35%, N: 0.0005 to 0.035%, and Al: 0.05 to 1.0%, satisfying [Al %]−(27/14)×[N %]≧0.05%, and having a balance of Fe and unavoidable impurities and forming an Al.sub.2O.sub.3 coating on the surface of a cutting tool by machining using a cutting tool coated on the surface contacting the machined material by metal oxides with a value of a standard free energy of formation at 1300° C. of that value of Al.sub.2O.sub.3 or more, and a machining method of the same.

The invention relates to a surface-hardened, rotationally symmetrical workpiece, to a hardening method and to a hardening apparatus. The proposed hardening apparatus comprises a machine frame on which two coaxially arranged rotary bearings designed to support a rotationally symmetrical workpiece are arranged, at least one rotary bearing being operatively connected to a drive device to generate rotation of the workpiece; and at lease one laser apparatus for generating focussed, high-energy radiation is arranged on said rotary bearing, said laser apparatus being movable in the axial direction, and the radiation being directed toward the workpiece.