Disclosed are a low-silicon and low-carbon equivalent GPa grade multi-phase steel plate/steel strip and a manufacturing method therefor. The steel plate/steel strip comprises the following components in percentages by weight: 0.03-0.07% of C, 0.1-0.5% of Si, 1.7-2.0% of Mn, P<0.02%, S<0.01%, N<0.01%, 0.01-0.05% of Al, 0.4-0.7% of Cr, 0.001-0.005% of B, and 0.07-0.15% of Ti, and also comprises one or both of 0.15-0.4% of Mo or 0.02-0.08% of Nb, with the balance being Fe and other inevitable impurities; and at the same time, the steel plate/steel strip satisfies: the content of available B*>0.001, the content of available B*=B-[Ti-3.4N-1.2(C—Nb/7.8)]/22, CE<0.58, and CE=C+Mn/6+(Cr+Mo+V)/5+(Si+Ni+Cu)/15. The steel plate has a tensile strength of >980 MPa and a yield strength of >780 MPa, and the hole expansion rate satisfies: if an original hole is a punched hole, the hole expansion rate is >50%; and if the original hole is a reamed hole, the hole expansion rate is >60%. The steel plate is mainly used in the preparation of vehicle chassis and suspension system parts.

A high-strength steel sheet with excellent delayed fracture resistance, having a tensile strength of 1700 MPa or larger, including a predetermined component composition, having a martensite structure whose ratio accounts for 95 area % or more of the entire metallographic structure, and having a transition metal carbide whose ratio accounts for 0.8 volume % or more of the entire metallographic structure.

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.

Provided according to one preferred aspect of the present invention are austenitic steel material having superb abrasion resistance and toughness, and a method for producing the austenite steel material. The austenitic steel material having superb abrasion resistance and toughness according to one preferred aspect of the present invention comprises, in wt %, 0.6-1.9% carbon (C); 12-22% manganese (Mn); 5% or lower (excluding 0%) chromium (Cr); 5% or lower (excluding 0%) copper (Cu); 0.5% or lower (excluding 0%) aluminum (Al); 1.0% or lower (excluding 0%) silicon (Si); 0.1% or lower (including 0%) phosphorous (P); 0.02% or lower (including 0%) sulfur (S); and the rest in Fe and unavoidable impurities, and has the microstructure comprising, by surface area fraction, 97% or higher (including 100%) austenite and 3% or lower (including 0%) carbide.

An exemplary embodiment in the present disclosure provides a grain-oriented electrical steel sheet containing, by wt %: 3.0 to 4.5% of Si; 0.05 to 0.2% of Mn; 0.015 to 0.035% of Al; 0.0015% or less (excluding 0%) of C; 0.0015% or less (excluding 0%) of N; 0.0015% or less (excluding 0%) of S; and a balance of Fe and other unavoidable impurities, wherein the grain-oriented electrical steel sheet satisfies the following Relational Expressions 1 and 2:

(W.sub.13/50/W.sub.17/50)≤0.57  [Relational Expression 1]

(W.sub.15/50/W.sub.17/50)≤0.76  [Relational Expression 2] where Wx/y represents a core loss value under conditions in which a magnitude of an applied magnetic field is x/10 T and a frequency is y Hz.

The present cooling device includes: when cooling regions obtained by dividing an entire cooling region into a plurality of portions in a steel sheet conveyance direction and three or more portions in a width direction are set as divided cooling surfaces, a cooling water nozzle 23 and a switching device that switches between collision and non-collision of cooling water jetted from the cooling water nozzle 23 with the divided cooling surface, the cooling water nozzle 23 and the switching device provided for each of the divided cooling surfaces; and a control device that controls operation of the switching device based on a width-direction temperature distribution. The cooling water nozzle 23 has a jet axis P inclined with respect to a vertical line to the entire cooling region when viewed in the steel sheet conveyance direction, and the cooling water goes to the side opposite to the cooling water nozzle 23 in the width direction after colliding with the divided cooling surface.

The invention relates to a method and a device for rapidly cooling a metal strip and removing residues present on the strip after this cooling, wherein the residues are formed during a cooling of said metal strip by a non-oxidizing liquid solution for the metal strip and a stripping liquid solution for the oxides present on the surface of the strip, or by a mixture of this liquid solution and a gas.

A spray quenching system including a quench box configured to receive a part for quenching. The system may include mechanical arms disposed within the quench box and thermocouples disposed on the mechanical arms that may be moved to contact the part surface. The system may include non-contact temperature sensors within the quench box that measure the temperature part surface, and spray nozzles within the quench box that spray the part with a quenching fluid. The system may include a controller in electronic communication with the mechanical arms, the spray nozzles, the thermocouples, and the non-contact temperature sensors, that is configured to initiate a quenching process, receive temperature data, analyze the temperature data to determine a temperature difference value, determine that the temperature difference value exceeds a threshold temperature difference value, and adjust the quenching process if the temperature difference value exceeds the threshold temperature difference value.

A device and a method for cooling metal strips or sheets conveyed on a conveyor line, in particular hot-rolled strips in the outlet of a rolling train. For these purposes, the device includes at least one cooling beam extending across the width of the conveyor line, and the cooling beam features a connection point to which a supply tube for cooling liquid can be connected, and a number of discharge openings arranged along a longitudinal axis of the cooling beam, such that cooling liquid can be discharged through the discharge openings in the direction of the metal strip or sheet that is to be cooled. Associated with each of the individual discharge openings is a respectively adjusted flow area, such that the flow areas of the respective discharge openings decrease in a direction leading away from the connecting point along the longitudinal axis of the cooling beam.

A device and a method for cooling metal strips or sheets conveyed on a conveyor line, in particular hot-rolled strips in the outlet of a rolling train. For these purposes, the device includes at least one cooling beam extending across the width of the conveyor line, and the cooling beam features a connection point to which a supply tube for cooling liquid can be connected, and a number of discharge openings arranged along a longitudinal axis of the cooling beam, such that cooling liquid can be discharged through the discharge openings in the direction of the metal strip or sheet that is to be cooled. Associated with each of the individual discharge openings is a respectively adjusted flow area, such that the flow areas of the respective discharge openings decrease in a direction leading away from the connecting point along the longitudinal axis of the cooling beam.