An annealing furnace for annealing a strand of steel. The annealing furnace including a first heating apparatus for heating the strand during operation of the annealing furnace. A transport device advances the strand in a direction of transport through the annealing furnace during operation of the annealing furnace. The annealing furnace also includes a first cooling device for cooling the outer surface of the strand with a gas guide in the direction of transport behind the first heater, wherein the gas guide is arranged in such a manner that a gas flows along the outer surface of the strand during operation of the annealing furnace for cooling the strand.

An essentially lead free steel having, in percent by weight (wt-%): Carbon: 0.39-0.43%; Manganese: 0.75-1.00%; Silicon: 0.15-0.35%; Chromium: 0.80-1.05%; Molybdenum: 0.15-0.25%; at least one of Tellurium: 0.003-0.090 wt-%, Selenium: 0.080-0.2 wt-%, Sulfur: 0.065-0.09% wt-%, and Bismuth: 0.03-0.1 wt-%; and the balance being Fe and normally occurring scrap steel impurities. A method for manufacturing an essentially lead free steel by subjecting a hot-rolled steel product to a heat treatment in which the steel product is subjected to a first temperature for a first duration; the steel product is subjected to a second temperature for a second duration, wherein the second temperature is less than the first temperature; and the steel product is subjected to a third temperature for a third time period, wherein the third temperature is greater than the second temperature; and cooling the steel product. After the heat treatment the steel is cold worked to the desired size.

A heat treatment device includes: a heating device that heats a treatment object; a cooling device including a cooling room that accommodates the treatment object heated by the heating device and into which a cooling medium used for cooling the treatment object is supplied; a pressurized gas supplier that supplies pressurized gas into the cooling room; a pressure relief valve that communicates internal and external areas of the cooling room with each other when the pressure relief valve is opened; a pressure sensor that measures the pressure inside the cooling room; and a controller that controls the pressure relief valve such that the pressure relief valve is opened when a measurement result of the pressure sensor is higher than or equal to a threshold value.

A first nitriding process step is performed in which a steel member is subjected to a nitriding process in a nitriding gas atmosphere having a nitriding potential with which a nitride compound layer having a phase or an phase is generated, and thereafter a second nitriding process step is performed in which the steel member is subjected to a nitriding process in a nitriding gas atmosphere having a nitriding potential lower than the nitriding potential in the first nitriding process step, to thereby precipitate the phase in the nitride compound layer. It is possible to generate the nitride compound layer having a desired phase mode uniformly all over a component to be treated and to manufacture a nitrided steel member high in pitting resistance and bending fatigue strength.

Methods of strengthening surface regions of high-strength transformation induced plasticity (TRIP) steel are provided. The method may comprise shot peening at least one region of an exposed surface of a hot-formed press-hardened component comprising a high-strength steel. Prior to shot peening, the component has a microstructure comprising about 5% by volume retained austenite in a matrix of martensite. The shot peening is conducted at a temperature of about 150 C. and forms at least one hardened surface region comprising about 2% by volume austenite. The TRIP steel may be zinc-coated and having a surface coating comprising zinc and substantially free of liquid metal embrittlement (LME). Zinc-coated hot-formed press-hardened components, including automotive components, formed from such methods are also provided.

Systems and methods for locally softening high strength steel are disclosed. One method may include heat treating one or more local regions of a steel component having a hardness of at least 450 HV to soften the local region(s) to a hardness of at most 250 HV. The heat treating may include heating only the local region(s) to a target temperature above an A.sub.C1 temperature of the component and below an A.sub.C3 temperature of the component. In another method, the heat treating may include heating only the local region(s) to a first target temperature above an A.sub.C3 temperature of the component, cooling the local region(s) to below an A.sub.C1 temperature of the component, and isothermally holding the local region(s) at a second target temperature below the A.sub.C1 temperature. The locally softened region(s) may allow for improved joining and/or trimming of the component.

The present invention suppresses leakage of combustion gas from a contact surface. A cylinder head (20) is attached to a cylinder block. The surface (26) of the side of the cylinder head (20) that is attached to the cylinder block includes a first region (AH1) and a second region (AH2) that has higher hardness than the first region (AH1).

In heating step S101, a steel sheet is heated and made in an austenite state. In heating step S101, the whole region of the steel sheet is evenly heated, and the whole region of the steel sheet is made in the austenite state. In cooling step S102, only a first region set on the steel sheet in the austenite state is forcibly cooled (rapidly cooled) within a temperature range of a range where martensitic transformation does not occur. In cooling step S102, a second region other than the first region is cooled by natural cooling to maintain a state in which a temperature is higher than in the first region.

A method for producing an R-T-B-based sintered magnet comprises a sintering step for sintering a shaped product of R-T-B-based alloy powder. This sintering step includes: a first step for heating the shaped product at a first sintering temperature T1 to prepare a first sintered body; a cooling step for lowering the temperature of the first sintered body to a cooling temperature T0; and a second step for heating the first sintered body at a second sintering temperature T2 to prepare a second sintered body. The first sintering temperature T1 and the second sintering temperature T2 are higher than 900? C., and the cooling temperature T0 is 900? C. or lower. A first sintering time t1 for which the first sintering temperature T1 is maintained in the first step is shorter than a second sintering time t2 for which the second sintering temperature T2 is maintained in the second step.

An alloy consisting of titanium, zirconium, cobalt, and nickel, and its fabrication.