The present invention relates to an austenitic light-weight high-strength steel with excellent properties of welds, and a method of manufacturing the same, the method including: (a) hot-rolling a steel including 20 wt % to 30 wt % of manganese (Mn), 6 wt % to 12 wt % of aluminum (Al), 0.6 wt % to 1.5 wt % of carbon (C), 0.3 wt % to 0.95 wt % of vanadium (V), and a remaining amount of iron (Fe) and other unavoidable impurities; (b) homogenizing the hot-rolled steel; and (c) aging the homogenized steel.

The present invention relates to an austenitic light-weight high-strength steel with excellent properties of welds, and a method of manufacturing the same, the method including: (a) hot-rolling a steel including 20 wt % to 30 wt % of manganese (Mn), 6 wt % to 12 wt % of aluminum (Al), 0.6 wt % to 1.5 wt % of carbon (C), 0.3 wt % to 0.95 wt % of vanadium (V), and a remaining amount of iron (Fe) and other unavoidable impurities; (b) homogenizing the hot-rolled steel; and (c) aging the homogenized steel.

An endless metal belt having an excellent abrasion resistance and a method for manufacturing such endless metal belts, capable of sufficiently reducing a tensile stress related to a metal ring in the innermost layer are provided. An endless metal belt includes a belt member formed by laminating a plurality of metal rings; and an element supported by the belt member, in which among the plurality of metal rings, a metal ring in an innermost layer is formed by a maraging steel plate, and another metal ring includes a nitride layer on its surface, and has a specific chemical composition; a tensile strength of the another metal ring is 1,700 MPa or higher; and a surface hardness of the nitride layer is HV800 to HV950.

The invention relates to a cold work tool steel. The steel comprises the following main components (in wt. %): C 0.5-2, N 1.3-3, Si 0.05-1.2, Mn 0.05-1, Cr 2.5-5.5, Mo 0.8-2.2, V 6-18, with a balance of optional elements, iron, and impurities.

The invention relates to a cold work tool steel. The steel comprises the following main components (in wt. %): C 0.5-2, N 1.3-3, Si 0.05-1.2, Mn 0.05-1, Cr 2.5-5.5, Mo 0.8-2.2, V 6-18, with a balance of optional elements, iron, and impurities.

The present invention relates to a steel for a mold including: on % by mass basis, 0.55%?C?0.70%; 0.30%?Si?0.60%; 0.55%?Mn?1.2%; 5.7%?Cr?6.9%; 1.2%?Mo+W/2?1.6%; 0.55%?V?0.79%; and 0.005%?N?0.1%, with the remainder being Fe and inevitable impurities including, Al?0.020%, Ni?0.20%, S?0.0015%, and Cu?0.10%, and satisfying P1?24 and 4.9?P2?7.3, P1 and P2 being a value obtained based on the following formula (1) and (2), respectively, P1=45?13.6[Si]?7.0([Mo]+[W]/2)?12.9[Ni] (1), P2=7.4[V]+15.8[N]+38.6[Al] (2) in which [M] represents a content of an element M in % by mass basis, and relates to a mold including the steel for a mold.

A blank material is formed from a steel sheet, a first quenching of the blank material is performed, and a second quenching of the blank material is performed after the first quenching. When the first quenching is performed, the blank material is heated to a first temperature of not lower than (Ac3 point50) C. nor higher than 1200 C. at an average heating rate of 2 C./sec or more, and the blank material is cooled from the first temperature to a second temperature of 250 C. or lower. When the second quenching is performed, the blank material is heated from the second temperature to a third temperature of not lower than (Ac3 point50) C. nor higher than 1200 C. at an average heating rate of 2 C./sec or more, and the blank material is cooled from the third temperature to a fourth temperature of 250 C. or lower. Forming of the blank material is performed in the first quenching or the second quenching or both of the above.

A blank material is formed from a steel sheet, a first quenching of the blank material is performed, and a second quenching of the blank material is performed after the first quenching. When the first quenching is performed, the blank material is heated to a first temperature of not lower than (Ac3 point50) C. nor higher than 1200 C. at an average heating rate of 2 C./sec or more, and the blank material is cooled from the first temperature to a second temperature of 250 C. or lower. When the second quenching is performed, the blank material is heated from the second temperature to a third temperature of not lower than (Ac3 point50) C. nor higher than 1200 C. at an average heating rate of 2 C./sec or more, and the blank material is cooled from the third temperature to a fourth temperature of 250 C. or lower. Forming of the blank material is performed in the first quenching or the second quenching or both of the above.

A method of producing an endless metal ring includes welding ends of a maraging steel plate such that the maraging steel plate has a ring shape, annealing the maraging steel plate with the ring shape in a furnace at 845 C. or higher, and nitriding the annealed maraging steel plate, wherein, during the annealing, a dew point temperature indicating an amount of water in the furnace is adjusted such that a value of the dew point temperature [ C.] is equal to or higher than a value obtained by subtracting 35 from time [min] at an annealing temperature of 845 C. or higher.

A nanocrystalline bainitic steel consisting of, by weight percentage: 0.3% to 0.6% carbon; 9.0% to 20.0% nickel; up to 10% cobalt; 1.0% to 4.5% aluminium; up to 0.5% molybdenum; up to 0.5% manganese; up to 0.5% tungsten; up to 3.0% chromium; and the balance being iron and impurities.