A Roughly shaped material for induction hardened components including: a. steel as a base metal including, as a chemical composition, by mass %, C: 0.35% to 0.6%, Si: 0.02% to 2.0%, Mn: 0.35% to 1.5%, Al: 0.001% to 0.5%, Cr: 0.05% to 2.0%, S: 0.0001% to 0.05%, N: 0.003% to 0.0120%, P: 0.03% or less, O: 0.0050% or less, an iron nitride layer having a thickness of 0.1 m to 50 m in a depth direction is formed at a surface, and a volume fraction of a phase, which is a Fe nitride, in the iron nitride layer, is 80% or more.

A Roughly shaped material for induction hardened components including: a. steel as a base metal including, as a chemical composition, by mass %, C: 0.35% to 0.6%, Si: 0.02% to 2.0%, Mn: 0.35% to 1.5%, Al: 0.001% to 0.5%, Cr: 0.05% to 2.0%, S: 0.0001% to 0.05%, N: 0.003% to 0.0120%, P: 0.03% or less, O: 0.0050% or less, an iron nitride layer having a thickness of 0.1 m to 50 m in a depth direction is formed at a surface, and a volume fraction of a phase, which is a Fe nitride, in the iron nitride layer, is 80% or more.

A method of forming a golf club head assembly includes aligning a faceplate with a recess of a club head; welding the faceplate to the club head; then, after welding the faceplate, heating the club head and the faceplate to at least a solvus temperature of the faceplate for a predetermined amount of time; and then, after heating the club head and the faceplate, allowing the club head and the faceplate to air cool.

A nitrided steel part excellent in bending straightening ability and bending fatigue characteristic enabling reduction of size and decrease of weight of parts or enabling demand for high load capacities to be met, using as a material a steel material containing, by mass %, C: 0.2 to 0.6%, Si: 0.05 to 1.5%, Mn: 0.2 to 2.5%, P: 0.025% or less, S: 0.003 to 0.05%, Cr: 0.05 to 0.5%, Al: 0.01 to 0.05%, and N: 0.003 to 0.025%, and having a balance of Fe and impurities, having formed on the steel surface a compound layer of a thickness 3 m or less comprising iron, nitrogen, and carbon and a hardened layer formed below the compound layer, and having an effective hardened layer depth of 160 to 410 m.

A nitrided steel part excellent in pitting resistance and bending fatigue characteristic enabling reduction of size and decrease of weight of parts or enabling demand for high load capacities to be met, using as a material a steel material containing, by mass %, C: 0.05 to 0.25%, Si: 0.05 to 1.5%, Mn: 0.2 to 2.5%, P: 0.025% or less, S: 0.003 to 0.05%, Cr: over 0.5 to 2.0%, Al: 0.01 to 0.05%, and N: 0.003 to 0.025%, having a balance of Fe and impurities, having formed on the steel surface a compound larger of a thickness 3 m or less containing iron, nitrogen, and carbon and a hardened layer formed below the compound layer, and having an effective hardened layer depth of 160 to 410 m.

A method for producing a hardened steel component in which a sheet blank is stamped out and the stamped sheet blank is heated to a temperature Ac.sub.3 and as needed, is kept at this temperature for a predetermined time in order to carry out the austenite formation and then the sheet blank, which has been heated all over or only in some regions, is transferred to a forming die, is formed in the forming die, and in the forming die, is cooled at a speed that lies above the critical hardening speed and is thus hardened or else the sheet blank is completely cold formed and the formed sheet blank is heated all over or only in some regions to a temperature >Ac.sub.3 and as needed, is kept at this temperature for a predetermined time in order to carry out the austenite formation and then the sheet blank, which has been heated and formed all over or only in some regions, is transferred to a hardening die, and is hardened in the hardening die at a speed that lies above the critical hardening speed; the steel material is adjusted in a transformation-delaying way so that at a forming temperature that lies in the range from 450 C. to 700 C., a quench hardening takes place through the transformation of the austenite into martensite; after the heating and before the forming, an active cooling takes place in which the sheet blank or parts of the sheet blank is/are cooled at a cooling speed of >15 K/s; for the homogeneous, contactless cooling of hot sheet blanks or components, a cooling apparatus and an article with a hot surface are moved relative to each other; the cooling apparatus has at least two cooling blades or cooling columns that are parallel to and spaced apart from each other; oriented toward the sheet blank to be cooled or the component to be cooled, the cooling blades or cooling columns have a nozzle edge with nozzles; the nozzles direct a cooling fluid at the surface of the sheet blank or the component and after the cooling fluid contacts the hot surface, it flows away in the space between the blades or cooling columns.

A highway safety protective fence includes a processed steel guardrail board and a protective sleeve, wherein the protective sleeve is sleeved to an outer surface of the processed steel guardrail board. Furthermore, a method for manufacturing the highway safety protective fence includes steps of: conveying an original steel guardrail board to a quenching furnace through a temperature withstanding ceramic stick, quenching, conveying to a constant temperature furnace, staying, conveying to a quenching oil solution tank, cooling in sequence and obtaining a processed steel guardrail board; conveying the processed steel guardrail board to a rubber coating machine through a conveying belt, and packaging the processed steel guardrail board with the protective sleeve to obtain the highway safety protective fence. In the highway safety protective fence provided by the present invention, the steel guardrail board is quenched to greatly increase the safety factor.

To provide a steel for high-strength bolts, which can exhibit the sufficient delayed fracture resistance under the severe environment, and also has excellent bolt formability. The steel for high-strength bolts of the present invention includes C: 0.10 to 0.30%; and Ni: 0.4 to 0.7%, with the chemical composition being appropriately adjust, and satisfies the following formulas (1) and (2):
0.85[C]+[Si]/7+[Mn]/5+[Ni]/20+[Cr]/9+[Mo]/21.3(1)
[C](0.07[Mo]+0.20[V])0.20(2).

A method of hot forming hybrid parts wherein side-by-side with a thin-walled piece of steel stock, which has been heated to austenite temperature, another piece of stock of another formable metal is placed, The processing temperature of this formable metal corresponds to the temperature at which quenching of the steel stock is interrupted within an interval between the M.sub.s and M.sub.f temperatures. The steel stock and formable metal are then formed together, while the temperature decreases to a temperature which is close to the forming tool temperature. Next, the resulting semi-finished product is cooled to the ambient temperature.

A method of hot forming hybrid parts wherein side-by-side with a thin-walled piece of steel stock, which has been heated to austenite temperature, another piece of stock of another formable metal is placed, The processing temperature of this formable metal corresponds to the temperature at which quenching of the steel stock is interrupted within an interval between the M.sub.s and M.sub.f temperatures. The steel stock and formable metal are then formed together, while the temperature decreases to a temperature which is close to the forming tool temperature. Next, the resulting semi-finished product is cooled to the ambient temperature.