The invention relates to a 9Ni steel plate for ship LNG storage tank with high strength and low yield ratio. According to the mass percentage, the chemical constituents are C: 0.02-0.05%, Si: 0.10-0.30%, Mn: 0.50-0.80%, Ni: 8.90-9.50%, P: ≤0.0070%, s: ≤0.0020%, Cr: 0.10-0.25%, Alt: 0.010-0.035%, Nb: 0.010-0.020%, Ca: 0.0005-0.0030%, O: ≤0.0012%, N: ≤0.004%, H: ≤0.00015%, and the balance is Fe and unavoidable impurity elements. The production process flow is: smelting in a converter or electric furnace->RH vacuum degassing->LF refining->RH high vacuum degassing->Ca Treatment->continuous casting->slab slow cooling treatment->slab surface cleaning->heating->rolling ->quenching->tempering. For the 9Ni steel, especially the 9Ni thin steel plate, the invention adopts the constituents design of low C, 9% Ni, addition of Nb and Cr. The steel plate is subject to high-temperature hot rolling, and then QLT heat treatment process to obtain 9Ni steel with good strength, toughness and low yield ratio.

A 780 MPa-grade ultra-high reaming steel having high surface quality and high performance stability, and a manufacturing method therefor. The ultra-high reaming steel comprises the following components in percentage by weight: 0.03-0.08% of C, Si≤0.2%, 0.5-2.0% of Mn, P≤0.02%, S≤0.003%, 0.01-0.08% of Al, N≤0.004%, 0.05-0.20% of Ti, 0.1-0.5% of Mo, Mg≤0.005%, O≤0.0030%, and the remainder being Fe and other inevitable impurities. The ultra-high reaming steel of the present invention achieves matching between good structure homogeneity and performance homogeneity and excellent strength, plasticity, and ultra-high reaming rate; the ultra-high reaming steel has yield strength greater than or equal to 750 MPa, tensile strength greater than or equal to 780 MPa, an elongation A50 greater than or equal to 15%, and a reaming rate greater than or equal to 70%; moreover, appearance of red iron scales on the surface of a steel plate can be avoided, thereby improving the surface quality of pickled high-strength steel; the ultra-high reaming steel can satisfy user requirements well, and can be applied to parts of passenger vehicle chassis components such as a control arm and an auxiliary frame, which require high strength and thinning.

A 980 MPa-grade full-bainite ultra-high hole expansion steel and a manufacturing method therefor. The hole expansion steel has the following chemical compositions in percentage by weight: 0.05-0.10% of C, Si≤2.0%, 1.0-2.0% of Mn, P≤0.02%, S≤0.003%, 0.02-0.08% of Al, N≤0.004%, 0.1-0.5% of Mo, 0.01-0.05% of Ti, O≤0.0030%, the remainder being Fe, and other inevitable impurities. The ultra-high hole expansion steel in the present invention has yield strength ≥800 MPa, tensile strength ≥980 MPa, and a hole expansion rate up to 60% or more, and can be applied in the parts of chassis components such as a control arm and an auxiliary frame, which require high strength thinning and complex forming, of passenger vehicles.

A material characteristic value prediction system that can predict material characteristic values with high accuracy is provided. Also provided is a method of manufacturing a metal sheet that can improve the product yield rate, by changing manufacturing conditions of subsequent processes. The material characteristic value prediction system (100) includes a material characteristic value predictor configured to acquire input data including line output factors in a metal sheet manufacturing line, disturbance factors, and component values of a metal sheet being manufactured, and predict material characteristic values of the manufactured metal sheet using a prediction model configured to take the input data as inputs, wherein the prediction model includes a machine learning model generated by machine learning and configured to take the input data as inputs and output production condition factors, and a metallurgical model configured to take the production condition factors as inputs and output the material characteristic values.

Methods for forming carbon-based lubricious and/or wear-protective films in situ on the surface of steel alloys are provided. The methods use chromium-containing steel alloys, molybdenum-containing steel alloys, and steel alloys that contain both copper and nickel. When such alloys are subjected to a rubbing motion in the presence of a hydrocarbon fluid, the chromium, molybdenum, copper, and nickel in the steel alloy catalyzes the formation of solid carbon-containing films that reduce the friction, wear, or both of the contacting surfaces.

A high-grade non-oriented silicon steel and a production method are provided. The non-oriented silicon steel includes the following chemical components in percent by mass: 0.002-0.004% of C, not greater than 0.003% of S, 1.4-1.7% of Si, 0.7-0.95% of Mn, not greater than 0.03% of P, 0.015-0.035% of Sn; and 11×([Si]-1.4%)=14×([Mn]-0.7%). In the production method, the heating temperature of a continuous casting billet is 1,120-1,150° C.; the finishing temperature in finish rolling is 890±15° C.; the rolling reduction of the last pass of finish rolling is not less than 30%, the total rolling reduction of the last two passes of finish rolling is not less than 50%, and the coiling temperature is 650±20° C.; normalizing treatment is avoided before acid continuous rolling.

Disclosed are a 980 MPa-grade bainite high hole expansion steel and a manufacturing method therefor. The steel contains the following chemical components in percentages by weight: 0.05-0.10% of C, 0.5-2.0% of Si, 1.0-2.0% of Mn, P≤0.02%, S≤0.003%, 0.02-0.08% of Al, N≤0.004%, Mo≥0.1%, 0.01-0.05% of Ti, Cr≤0.5%, B≤0.002%, O≤0.0030%, and the balance of Fe and other inevitable impurities. The high hole expansion steel of the present invention has a yield strength of ≥800 MPa and a tensile strength of ≥980 MPa, has a good elongation rate (the transverse A.sub.50 being ≥11%) and hole expansion performance (the hole expansion ratio being ≥40%), and can be applied to a position on a chassis part of a passenger car, such as a control arm and a vice frame, where high strength and thinning are required.

A low-carbon martensitic high hole expansion steel with a tensile strength above 980 MPa, and a manufacturing method therefor, the weight percentage of the chemical components thereof being: C 0.03-0.10%, Si 0.5-2.0%, Mn 1.0-2.0%, P≤0.02%, S≤0.003%, Al 0.02-0.08%, N≤0.004%, Mo 0.1-0.5%, Ti 0.01-0.05%, and O≤0.0030%, and the remainder being Fe and other inevitable impurities. The high hole expansion steel of the present invention has a yield strength of ≥800 MPa and tensile strength of ≥980 MPa, a lateral extension rate A50≥8%, and a hole expansion ratio of ≥30%, passes cold bending performance tests (d≤4a, 180°), and can be used for passenger car chassis parts that require high strength and thinning such as control arms and sub-frames.

The invention relates to a non-grain-oriented flat metal product, which inter alia has comparatively high weight proportions of Mn and Cr. The invention also relates to a method of production and to a use.

One aspect of the present invention relates to a plated steel sheet for hot press forming, having an excellent impact property.