A steel sheet for hot pressing includes in a chemical composition, in percent by mass, C of 0.1% to 0.4%, Si of greater than 0% to 2.0%, Mn of 0.5% to 3.0%, P of greater than 0% to 0.015%, S of greater than 0% to 0.01%, F3 of 0.0003% to 0.01%, N of greater than 0% to 0.05%, Al in a content of 2[N]% to 0.3% at a Si content of greater than 0.5% to 2.0%; or Al in a content of (0.20+2[N]-0.40[Si]N)% to 0.3% at a Si content of 0% to 0.5%, where [N] and [Si] are contents of N and Si, respectively, in mass percent, with the remainder being iron and inevitable impurities, where contents of Ti, Zr, Hf, and Ta, of the inevitable impurities, are each controlled to 0.005% or lower. The steel sheet includes nitride-based inclusions with an equivalent circle diameter of 1 m or more in a number density of 0.10 per square millimeter.

The present invention relates to a thermal treatment furnace containing a thermal treatment chamber (1b) in which a thin metal sheet (20) is continuously conveyed horizontally while being floated by air (21), in which the thermal treatment chamber (1b) contains a plurality of air injection nozzles (6) and a plurality of mist spray nozzles (8) that are arranged along a pass line (PL) of the thin metal sheet (20) in the thermal treatment chamber (1b), on a lower side and an upper side of the pass line (PL) and so as to be orthogonal to the pass line (PL) in a side view.

Titanium-free alloy which has great resistance to pitting and crevice corrosion and a high yield point in the strain-hardened state and includes (in wt %) a maximum of 0.02% C, a maximum of 0.01% S, a maximum of 0.03% N, 20.0-23.0% Cr, 39.0-44.0% Ni, 0.4-<1.0% Mn, 0.1-<0.5% Si, >4.0-<7.0% Mo, a maximum of 0.15% Nb, >1.5-<2.5% Cu, 0.05-<0.3% Al, a maximum of 0.5% Co, 0.001-<0.005% B, 0.005-<0.015% Mg, the remainder consisting of Fe and smelting-related impurities.

A method of machining a screw is provided that is capable of preventing formation of a protruding section at a thread tip section. A thread is formed by cutting on a cylindrical body, and a surface of the thread is plastically deformed by rolling. Because of the cutting, a width between-side surfaces of a thread tip section is in a narrowed state as compared to a normal width. This width is narrowed toward a tip of the thread while a thread body section has a width expanded as compared to a normal width. Consequently, the side surfaces are formed to bulge by an excess thickness portion as compared to normal side surfaces. The rolling plastically deforms both side surfaces to cause the excess thickness portion to plastically flow toward the side surfaces.

A bolt is provided that has high strength and excellent hydrogen embrittlement resistance characteristics. A bolt according to an embodiment of the present invention consists of, in mass %, C: 0.32 to 0.39%, Si: 0.15% or less, Mn: 0.40 to 0.65%, P: 0.020% or less, S: 0.020% or less, Cr: 0.85 to 1.25%, Al: 0.005 to 0.060%, Ti: 0.010 to 0.050%, B: 0.0010 to 0.0030%, N: 0.0015 to 0.0080%, 0: 0.0015% or less, Mo: 0 to 0.05%, V: 0 to 0.05%, Cu: 0 to 0.50%, Ni: 0 to 0.30%, and Nb: 0 to 0.05%, with the balance being Fe and impurities. The bolt satisfies Formula (1) and Formula (2), and has a tensile strength of 1000 to 1300 MPa and satisfies Formula (3).

4.910C+Si+2Mn+Cr+4Mo+5V6.1 (1)

Mn/Cr0.55 (2)

[dissolved Cr]/Cr0.70 (3)

A bolt is provided that has high strength and excellent hydrogen embrittlement resistance characteristics. A bolt according to an embodiment of the present invention consists of, in mass %, C: 0.32 to 0.39%, Si: 0.15% or less, Mn: 0.40 to 0.65%, P: 0.020% or less, S: 0.020% or less, Cr: 0.85 to 1.25%, Al: 0.005 to 0.060%, Ti: 0.010 to 0.050%, B: 0.0010 to 0.0030%, N: 0.0015 to 0.0080%, 0: 0.0015% or less, Mo: 0 to 0.05%, V: 0 to 0.05%, Cu: 0 to 0.50%, Ni: 0 to 0.30%, and Nb: 0 to 0.05%, with the balance being Fe and impurities. The bolt satisfies Formula (1) and Formula (2), and has a tensile strength of 1000 to 1300 MPa and satisfies Formula (3).

4.910C+Si+2Mn+Cr+4Mo+5V6.1 (1)

Mn/Cr0.55 (2)

[dissolved Cr]/Cr0.70 (3)

The present invention relates to a waste gate component for a turbo charger comprising an alloy comprising about 30 to about 42 wt.-% Ni, about 15 to about 28 wt.-% Cr, about 1 to about 5 wt.-% Cr, about 1 to about 4 wt.-% Ti, and at least about 20 wt.-% Fe, and to processes for preparing such a waste gate component.

The invention relates to a method for the progressive induction surface hardening of a closed curve trace of a workpiece, the closed curve trace and a hardening device being moved relative to one another in a feed mode to harden the closed curve trace starting from an initial zone to an end zone, an unhardened soft zone being provided. According to the invention, the workpiece is provided with a marking, the hardening device having a sensor for detecting said marking. The curve trace and the hardening device are moved relative to one another along the treatment direction until the senor detects the marking. Once the marking is detected, another movement takes place in the treatment direction before the hardening device is activated, the curve trace being hardened by the relative movement. The marking is again detected by means of the sensor and the hardening device is then deactivated. The invention also relates to an arrangement which is suitable for carrying out the method described.

A forming tool for hot forming and partially press hardening a workpiece made of sheet steel including a die, a punch, and a cooling device. The die is formed of a first die part and at least one second die part which is movable relative to the first die part, while the punch is formed of a first punch part and at least one second punch part which is movable relative to the first punch part, the at least one movable second die part and the at least one movable second punch part interacting with an opening device which causes the at least one second die part and the at least one second punch part to contact the workpiece with a shorter closing time than the first die part and the first punch part.

A method of manufacturing a hot press formed part by hot pressing a coated steel sheet that is obtained by forming a Zn-based coating layer on a surface of a steel sheet includes: heating the coated steel sheet to a temperature range of 750 C. or more and 1000 C. or less; cooling a surface of the coated steel sheet; and hot press forming the coated steel sheet under a condition that a surface temperature of the coated steel sheet is 400 C. or less and an average temperature of the coated steel sheet is 500 C. or more or a temperature of a center position of the coated steel sheet in a thickness direction is 530 C. or more.