Abstract: Disclosed in the present disclosure is a steel. Apart from 90% or more by mass Fe and inevitable impurities, the steel further contains the following chemical elements in percentage by mass: C: 0.22-0.33%, Si: 0.1-1.0%, Mn: 0.3-1.5%, Cr: 0.2-1.6%, Ni: 2.2-3.8%, Mo: 0.1-0.7%, Cu: 0.02-0.3%, Al: 0.01-0.045%, V: 0.01-0.25%, and N?0.013%. Further disclosed in the present disclosure is a method for manufacturing the steel, comprising: (1) smelting and casting; (2) forging or rolling, involving processing a casting blank to a finished product size by using a roll-in-one-heat process or roll-in-two-heat process; and (3) quenching and tempering: wherein the heating temperature of quenching is 860-1000° C., the holding time is 2-6 h, and water cooling is performed after the quenching; and the tempering temperature is 400-600° C., the holding time is 1-4 h, and air cooling to room temperature is performed after tempering.

Abstract: Disclosed are a steel for a high-temperature carburized gear shaft and a manufacturing method for the steel. The steel for the high-temperature carburized gear shaft comprises the following chemical components in percentage by mass: 0.17-0.22% of C, 0.05-0.35% of Si, 0.80-1.40% of Mn, 0.010-0.035% of S, 0.80-1.40% of Cr, 0.020-0.046% of Al, 0.006-0.020% of N, 0.002-0.030% of Nb, V?0.02%, and Ti?0.01%. Also disclosed is a manufacturing method for the steel for the high-temperature carburized gear shaft, comprising the steps of: smelting and casting; heating; forging or rolling; and finishing. By reasonably controlling chemical element compositions of the steel, the steel for the gear shaft in the present invention can maintain proper austenite grain size and stability at high temperature, maintains 5-8 grades of the austenite grain size before and after the high-temperature vacuum carburizing at 940-1050° C.

Abstract: Disclosed is a cold forged gear steel. In addition to Fe and inevitable impurities, the cold forged gear steel further comprises the following chemical elements in mass percentage: 0.15-0.17% of C, 0.10-0.20% of Si, 1.0-1.10% of Mn, 0.80-0.90% of Cr and 0.02-0.04% of Al. Correspondingly, further disclosed is a manufacturing method for the cold forged gear steel, comprising the steps of: (1) smelting and casting; (2) heating; (3) forging or rolling; and (4) spheroidizing annealing: heating to and keeping at 750-770° C., then cooling with a cooling rate of 5-15° C./h to and keeping at 700-720° C., cooling with a cooling rate of 3-12° C./h to and keeping at 660-680° C., and cooling with a cooling rate of 5-20° C./h to 500° C. or below, and then tapping and cooling.

Abstract: The present invention discloses a steel for bolts, which comprises the following chemical elements in percentage by mass in addition to Fe and inevitable impurities: C: 0.37 to 0.45%; Si: 0.01 to 0.08%; Mn: 0.45 to 0.80%; Cr: 0.90 to 1.30%; Mo: 0.20 to 0.45%; Ni: 0.10 to 0.30%; V: 0.15 to 0.30%; and Al: 0.015 to 0.035%. The present invention further discloses a method for manufacturing the steel for bolts, which comprises the following steps: (1) smelting; (2) casting; (3) rough rolling; (4) high-speed wire rolling; (5) Stelmor controlled cooling; and (6) heat treatment, wherein the holding temperature of spheroidizing heat treatment is 760 to 790° C. and the holding time is 4 to 12 h, followed by a slow cooling process after the holding with a cooling speed of lower than 40° C./h. The drawing area reduction rate of a coil rod is controlled to 5 to 30%. The heating temperature of quenching and tempering heat treatment is 850 to 950° C. The tempering temperature is 500 to 600° C.

Abstract: Disclosed is a non-quenched and tempered round steel with high strength, high toughness and easy cutting, comprising the following chemical elements in percentage by mass: C: 0.36-0.45%, Si: 0.20-0.70%, Mn: 1.25-1.85%, Cr: 0.15-0.55%, Ni: 0.10-0.25%, Mo: 0.10-0.25%, Al: 0.02-0.05%, Nb: 0.001-0.040%, V: 0.10-0.25%, S: 0.02-0.06%, and the balance being Fe and inevitable impurities. Also disclosed is a method for manufacturing the non-quenched and tempered round steel, comprising the steps of: S1: smelting and casting; S2: heating; S3: forging or rolling; and S4: finishing. The non-quenched and tempered round steel with high strength, high toughness and easy cutting described above has high strength, good impact toughness, elongation and cross-sectional shrinkage, and has good cutting performance and fatigue resistance, and can be used in situations requiring a high-strength steel material, such as automobiles and engineering machinery.

Abstract: A steel for mining chain and a manufacturing method thereof, wherein the steel has compositions by weight percentage: C: 0.20-0.28%, Si: 0.01-0.40%, Mn: 0.50-1.50%, P?0.015%, S?0.005%, Cr: 0.30-2.00%, Ni: 0.50-2.00%, Mo: 0.10-0.80%, Cu: 0.01-0.30%, Al: 0.01-0.05%, Nb: 0.001-0.10%, V: 0.001-0.10%, H?0.00018%, N?0.0150%, O?0.0020%, and the balance is Fe and inevitable impurities. The manufacturing method comprises steps of smelting, refining and vacuum treatment, casting, heating, forging or rolling, and quenching and tempering heat treatment processes. The steel in the present invention has high strength and good impact toughness, good elongation and reduction of area. The steel can also resist stress corrosion cracking and have good weather resistance, wear resistance and fatigue resistance, which can be used in scenarios where the steel having high strength and toughness is required, such as construction machinery and marine engineering.

Abstract: Disclosed are a steel with controlled steel ratio and a manufacturing method therefor. The steel comprises the following components in percentage by mass: C: 0.245-0.365%, Si: 0.10-0.80%, Mn: 0.20-2.00%, P:?0.015%, S:?0.003%, Cr: 0.20-2.50%, Mo: 0.10-0.90%, Nb: 0-0.08%, Ni: 2.30-4.20%, Cu: 0-0.30%, V: 0.01-0.13%, B: 0-0.0020%, Al: 0.01-0.06%, Ti: 0-0.05%, Ca:?0.004%, H:?0.0002%, N:?0.013%, O:?0.0020%, and the balance of Fe and inevitable impurities, wherein the components satisfy (8.57*C+1.12*Ni)?4.8% and 1.2%?(1.08*Mn+2.13*Cr)?5.6%. The steel has excellent low-temperature impact toughness and aging impact toughness at ?20° C. and ?40° C., a rationally controlled yield ratio, and ultra-high strength, ultra-high toughness, and ultra-high plasticity, which can be used in applications such as offshore platform mooring chains, mechanical structures, and automobiles that require high strength and toughness of the steel.

Abstract: Provided is a steel comprising the following chemical composition in percentage by mass: 0.150-0.250% of C, 0.10-0.50% of Si, 0.60-1.50% of Mn, 0.30-1.20% of Cr, 0.20-0.80% of Mo, 2.00-4.00% of Ni, 0-0.10% of Nb, 0.0010-0.0050% of B, 0-0.12% of V, 0.003-0.06% of Ti, 0.01-0.08% of Al, the balance being Fe and unavoidable impurities. Also provided is a steel bar and a manufacturing method thereof. The steel bar is made from the above steel. The manufacturing method comprises the steps of smelting and casting, heating, forging or rolling, quenching, and tempering.

Abstract: The invention discloses a high-strength steel plate, comprising the following chemical elements in mass percentages: C: 0.070-0.115%, Si: 0.20-0.50%, Mn: 1.80-2.30%, Cr: 0-0.35%, Mo: 0.10-0.40%, Nb: 0.03-0.06%, V: 0.03-0.06%, Ti: 0.002-0.04%, Al: 0.01-0.08%, B. 0.0006-0.0020%, N?0.0060%, O?0.0040% Ca: 0-0.0045%, and the balance of Fe and unavoidable impurities. The invention further discloses a process of manufacturing said high-strength steel plate.

Abstract: Provided is a low-yield-ratio high-strength-toughness thick steel plate with excellent low-temperature impact toughness, which comprises: 0.05%-0.11% of C, 0.10%-0.40% of Si, 1.60%-2.20% of Mn, S?0.003%, 0.20-0.70% of Cr, 0.20%-0.80% of Mo, 0.02%-0.06% of Nb, 3.60%-5.50% of Ni, 0.01%-0.05% of Ti, 0.01%-0.08% of Al, 0<N?0.0060%, 0<O?0.0040%, and 0<Ca?0.0045%, with the balance being Fe and inevitable impurities; in addition, Ni+Mn?5.5 is also satisfied. The manufacturing method for the above-mentioned steel plate comprises smelting, casting, heating, two-stage rolling, quenching, cooling after quenching, and tempering.

Abstract: The invention discloses an ultra-high obdurability steel plate having a low yield ratio, comprising the chemical elements in mass percentages of: C: 0.18-0.34%, Si: 0.10-0.40%, Mn: 0.50-1.40%, Cr: 0.20-0.70%, Mo: 0.30-0.90%, Nb: 0-0.06%, Ni: 0.50-2.40%, V: 0-0.06%, Ti: 0.002-0.04%, Al: 0.01-0.08%, B: 0.0006-0.0020%, N?0.0060%, O?0.0040%, Ca: 0-0.0045%, and the balance of Fe and other unavoidable impurities. The invention also discloses a process of manufacturing the steel plate, wherein the heating temperature is 1080-1250° C.; the quenching temperature is 860-940° C.; and the tempering temperature is 150-350° C.

Abstract: A steel plate with yield strength at an 890 MPa level and low welding crack sensitivity and a manufacturing method therefor. Weight percentages of components thereof are: C: 0.06-0.13 wt. %, Si: 0.05-0.70 wt. %, Mn: 1.20-2.30 wt. %, Mo: 0-0.25 wt. %, Nb: 0.03-0.11 wt. %, Ti: 0.002-0.050 wt. %, Al: 0.02-0.15 wt. %, and B: 0-0.0020 wt. %, where 2Si+3Mn+4Mo?8.5, and others being Fe and inevitable impurities. The use of controlled thermo-mechanical rolling and cooling technologies is beneficial to improvement of steel plate strength, plasticity and toughness. The yield strength of the steel plate is greater than 890 MPa, the tensile strength is greater than 950 MPa, the charpy impact work Akv (?20) is greater than or equal to 120 J, and the welding crack sensitivity indicator Pcm is less than or equal to 0.25%.

Abstract: Provided is a low-yield-ratio high-strength-toughness thick steel plate with excellent low-temperature impact toughness, which comprises: 0.05%-0.11% of C, 0.10%-0.40% of Si, 1.60%-2.20% of Mn, S?0.003%, 0.20-0.70% of Cr, 0.20%-0.80% of Mo, 0.02%-0.06% of Nb, 3.60%-5.50% of Ni, 0.01%-0.05% of Ti, 0.01%-0.08% of Al, 0<N?0.0060%, 0<O?0.0040%, and 0<Ca?0.0045%, with the balance being Fe and inevitable impurities; in addition, Ni+Mn?5.5 is also satisfied. The manufacturing method for the above-mentioned steel plate comprises smelting, casting, heating, two-stage rolling, quenching, cooling after quenching, and tempering.

Abstract: The invention discloses a high-strength steel plate, comprising the following chemical elements in mass percentages: C: 0.070-0.115%, Si: 0.20-0.50%, Mn: 1.80-2.30%, Cr: 0-0.35%, Mo: 0.10-0.40%, Nb: 0.03-0.06%, V: 0.03-0.06%, Ti: 0.002-0.04%, Al: 0.01-0.08%, B: 0.0006-0.0020%, N?0.0060%, O?0.0040%, Ca: 0-0.0045%, and the balance of Fe and unavoidable impurities. The invention further discloses a process of manufacturing said high-strength steel plate.

Abstract: The invention discloses an ultra-high obdurability steel plate having a low yield ratio, comprising the chemical elements in mass percentages of: C: 0.18-0.34%, Si: 0.10-0.40%, Mn: 0.50-1.40%, Cr: 0.20-0.70%, Mo: 0.30-0.90%, Nb: 0-0.06%, Ni: 0.50-2.40%, V: 0-0.06%, Ti: 0.002-0.04%, Al: 0.01-0.08%, B: 0.0006-0.0020%, N?0.0060%, O?0.0040%, Ca: 0-0.0045%, and the balance of Fe and other unavoidable impurities. The invention also discloses a process of manufacturing the steel plate, wherein the heating temperature is 1080-1250° C.; the quenching temperature is 860-940° C.; and the tempering temperature is 150-350° C.

Abstract: The present invention provides a steel plate having a low welding crack susceptibility and a yield strength of 800 MPa and a manufacturing method for the same. The steel plate having a low welding crack susceptibility comprises the following chemical components (wt. %: percent by weight): C: 0.03-0.08 wt. %, Si: 0.05-0.70 wt. %, Mn: 1.30-2.20 wt. %, Mo: 0.10-0.30 wt. %, Nb: 0.03-0.10 wt. %, V: 0.03-0.45 wt. %, Ti: 0.002-0.040 wt. %, Al: 0.02-0.04 wt. %, B: 0.0010-0.0020 wt. %, the balance being Fe and unavoidable impurities, and the welding crack susceptibility index meets the following formula: Pcm?0.20%. The thermo-mechanical controlled rolling and cooling processes is used to obtain an ultrafine bainite batten matrix structure, which increases the intensity, plasticity and toughness of the steel plate. The steel plate with a low welding crack susceptibility of the present invention has a yield strength of greater than 800 MPa, a tensile strength of greater than 900 MPa, a Charpy impact energy Akv (?20° C.

Abstract: The present invention provides a steel plate having a low welding crack susceptibility and a yield strength of 800 MPa and a manufacturing method for the same. The steel plate having a low welding crack susceptibility comprises the following chemical components (wt. %: percent by weight): C: 0.03-0.08 wt. %, Si: 0.05-0.70 wt. %, Mn: 1.30-2.20 w.t %, Mo: 0.10-0.30 wt. %, Nb: 0.03-0.10 wt. %, V: 0.03-0.45 wt. %, Ti: 0.002-0.040 wt. %, Al: 0.02-0.04 wt. %, B: 0.0010-0.0020 wt. %, the balance being Fe and unavoidable impurities, and the welding crack susceptibility index meets the following formula: Pcm?0.20%. The thermo-mechanical controlled rolling and cooling processes is used to obtain an ultrafine bainite batten matrix structure, which increases the intensity, plasticity and toughness of the steel plate. The steel plate with a low welding crack susceptibility of the present invention has a yield strength of greater than 800 MPa, a tensile strength of greater than 900 MPa, a Charpy impact energy Akv (?20° C.