Abstract: The present disclosure relates to methods and compositions of linepipe steels that transport one or both of crude oil and natural gas. More particularly, the present disclosure relates sulfide stress cracking resistance of carbon steels for use as linepipe in transporting crude oil and natural gas by alternative carbon steel compositions comprising relatively low-manganese contents and/or low-carbon contents, alone or in combination with hydrogen trapping precipitates.

Abstract: The present disclosure relates to methods and treatments of linepipe steels that transport one or both of crude oil and natural gas. More particularly, the present disclosure relates to sulfide stress cracking resistance of carbon steels for use as linepipe in transporting crude oil and natural gas by alternative thermo-mechanically controlled and/or one or more additional heat treatment processes.

Abstract: The present invention relates to ferrous alloys with high strength, cost-effective corrosion resistance and cracking resistance for refinery service environments, such as amine service under sweet or sour environments. More specifically, the present invention pertains to a type of ferrous manganese alloyed steels for high strength and cracking resistance and methods of making and using the same.

Abstract: A cold rolled, coated and post batch annealed steel sheet produced by a method is provided. The method includes cold rolling a steel sheet; coating the cold rolled steel sheet with a zinc or zinc alloy coating, the cold rolled, coated steel sheet having an initial hole expansion and an initial yield strength and post batch annealing the cold rolled, coated steel sheet at a tempering temperature in a range from 150 to 650° C., the post batch annealed steel sheet having a final hole expansion and a final yield strength. The steel sheet includes (in wt. %) C-0.1-0.3%, Mn-1-3%, Si-0.5-3.5%, Al-0.05-1.5% and Mo+Cr being between 0-1.0%. The final hole expansion is at least 80% greater than the initial hole expansion and the final yield strength is at least 30% greater than the initial yield strength.

Abstract: A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%?C?0.22%, 1.9%?Si?2.3%, 2.4%?Mn?3%, Al?0.5%, Ti?0.05%, Nb?0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

Abstract: A method for forming a cold rolled, coated and post batch annealed steel sheet is provided. The method includes cold rolling a steel sheet; coating the cold rolled steel sheet with a zinc or zinc alloy coating, the cold rolled, coated steel sheet having an initial hole expansion and an initial yield strength and post batch annealing the cold rolled, coated steel sheet at a tempering temperature in a range from 150 to 650° C., the post batch annealed steel sheet having a final hole expansion and a final yield strength. The steel sheet includes (in wt. %)C-0.1-0.3%, Mn-1-3%, Si-0.5-3.5%, Al-0.05-1.5% and Mo+Cr being between 0-1.0%. The final hole expansion is at least 80% greater than the initial hole expansion and the final yield strength is at least 30% greater than the initial yield strength.

Abstract: A method for producing a high strength steel sheet having a yield strength YS of at least 850 MPa, a tensile strength TS of at least 1180 MPa, a total elongation of at least 14% and a hole expansion ratio HER of at least 30%. The chemical composition of the steel contains: 0.15%?C?0.25%, 1.2%?Si?1.8%, 2%?Mn?2.4%, 0.1%?Cr?0.25%, Nb?0.05%, Ti?0.05%, Al?0.50%, the remainder being Fe and unavoidable impurities. The sheet is annealed at an annealing temperature TA higher than Ac3 but less than 1000° C. for more than 30 s, by cooling it to a quenching temperature QT between 275° C. and 325° C., at a cooling speed sufficient to have, just after quenching, a structure consisting of austenite and at least 50% of martensite, the austenite content en.) being such that the final structure can contain between 3% and 15% of residual austenite and between 85 and 97% of the sum of martensite and bainite, without ferrite, heated to a partitioning temperature PT between 420° C. and 470° C.

Abstract: A method for producing a high strength uncoated steel sheet having an improved strength and an improved formability, including the steps of: providing an uncoated steel sheet; annealing the sheet at an annealing temperature TA higher than 865° C. but less than 1000° C. for a time of more than 30 s; cooling the sheet down to a quenching temperature QT between 310° C. and 375° C., at a cooling speed of at least 30° C./s; heating the sheet up to a partitioning temperature PT between 370° C. and 470° C. and maintaining the sheet at the partitioning temperature for a partitioning time Pt between 50 s and 150 s; and cooling the sheet down to the room temperature.

Abstract: A method is for producing a high strength coated steel sheet having a yield stress YS>800 MPa, a tensile strength TS>1180 MPa, and improved formability and ductility. The steel contains: 15%?C?0.25%, 1.2%?Si?1.8%, 2%?Mn?2.4%, 0.1%?Cr?0.25%, Al?0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature higher than Ac3 and lower than 1000° C. for a time of more than 30 s, then quenched by cooling it to a quenching temperature QT between 250° C. and 350° C., to obtain a structure consisting of at least 60% of martensite and a sufficient austenite content such that the final structure contains 3% to 15% of residual austenite and 85% to 97% of martensite and bainite without ferrite, then heated to a partitioning temperature PT between 430° C. and 480° C. and maintained at this temperature for a partitioning time Pt between 10 s and 90 s, then hot dip coated and cooled to the room temperature.

Abstract: A steel sheet made of a steel having a chemical composition containing in weight %: 0.13%?C?0.22%, 1.2%?Si?1.8%, 1.8%?Mn?2.2%, 0.10%?Mo?0.20%, Nb?0.05%, Ti?0.05%, Al?0.5%, a remainder being Fe and unavoidable impurities. The steel sheet has a yield strength of at least 850 MPa, a tensile strength of at least 1180 MPa, a total elongation of at least 13% and a hole expansion ratio HER of at least 30%.

Abstract: A cold rolled and coated steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.140%?Carbon?0.2%, 1.5%?Manganese?2.15%, 0.5%?Silicon?0.8%, 0.4%?Aluminum?0.8%, 0%?Phosphorus?0.09%, 0%?Sulfur?0.09%, 0%?Nitrogen?0.09%, 0.01%?Niobium?0.1%, 0.01%?Titanium?0.1%, and can contain one or more of the following optional elements 0%?Chromium?0.1%, 0%?Nickel?0%, 0%?Calcium?0.005%, 0%?Copper?2%, 0%?Molybdenum?0.5%, 0%?Vanadium?0.1%, 0%?Boron?0.003%, 0%?Cerium?0.1%, 0%?Magnesium?0.010%, 0%?Zirconium?0.010% the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet including in area fraction, 40 to 60% Inter-critical Ferrite, 25 to 45% Transformed Ferrite, 8% to 20% and 5% to 20% Fresh Martensite, 0 to 10% Bainite, wherein the cumulated amount of Inter-critical and Transformed Ferrite is between 75% and 85%.

Abstract: A method for producing a dual phase steel sheet is provided. The method includes providing a dual phase hot rolled steel sheet having a microstructure including ferrite and martensite and a composition including 0.1 to 0.3 wt. % C, 1.5 to 2.5 wt. % Si and 1.75 to 2.5 wt. % Mn. The steel sheet is annealed at a temperature from 750 to 875° C., water quenched to a temperature from 400 to 420° C. and subject to overaging at the temperature from 400 to 420° C. to convert the martensite in the hot rolled steel sheet to tempered martensite. The overaging is sufficient to provide the hot rolled steel sheet with a hole expansion ratio of at least 15%.

Abstract: A method for producing a cold rolled and hot dip coated steel sheet is provided. The method includes casting a steel into a slab, reheating, hot rolling, cooling, coiling, descaling and cold rolling the slab. The cold rolled steel sheet is annealed so a layer of iron oxide forms on the surface with an internal oxidation underneath. The sheet is then heated so the surface is oxidized and the layer of iron oxide is fully reduced to obtain an internally oxidized depth between 200 nm and 100 ?m which includes one or more of Si, Mn, Al, Ti containing oxides. The sheet is then hot dip coated and cooled.

Abstract: A method for producing a high strength coated steel sheet having a yield strength YS of at least 800 MPa, a tensile strength TS of >1180 MPa, a total elongation >14% and a hole expansion ratio HER >30%. The steel contains in weight %: 0.13%?C?0.22%, 1.2%?Si?1.8%, 1.8%?Mn?2.2%, 0.10%?Mo?0.20%, Nb?0.05%, Al?0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature TA higher than Ac3 but less than 1000° C. for more than 30 s, then quenched by cooling temperature QT between 325° C. and 375° C., at a cooling speed sufficient to obtain a structure consisting of austenite and at least 60% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85 and 97% of the sum of martensite and bainite, without ferrite, then heated to a partitioning temperature PT between 430° C. and 480° C.

Abstract: A method for forming a cold rolled, coated and post batch annealed steel sheet is provided. The method includes cold rolling a steel sheet; coating the cold rolled steel sheet with a zinc or zinc alloy coating, the cold rolled, coated steel sheet having an initial hole expansion and an initial yield strength and post batch annealing the cold rolled, coated steel sheet at a tempering temperature in a range from 150 to 650° C., the post batch annealed steel sheet having a final hole expansion and a final yield strength. The steel sheet includes (in wt. %) C—0.1-0.3%, Mn—1-3%, Si—0.5-3.5%, Al—0.05-1.5% and Mo+Cr being between 0-1.0%. The final hole expansion is at least 80% greater than the initial hole expansion and the final yield strength is at least 30% greater than the initial yield strength.

Abstract: A coated steel sheet includes a chemical composition including in weight %: 0.13%?C ?0.22%; 1.2%?Si?1.8%; 1.8%?Mn?2.2%; 0.10%?Mo?0.20%; Nb?0.05%; Al?0.5%; Ti?0.05%; and a remainder being Fe and unavoidable impurities. A structure of the steel sheet consists of, by volume fraction, 3% to 15% of residual austenite and 85% to 97% of martensite and bainite. The structure includes at least 65% of martensite and does not including ferrite. At least one face of the coated steel sheet includes a metallic coating. The steel sheet has a yield strength of at least 800 MPa, a tensile strength of at least 1180 MPa, a total elongation of at least 14% and a hole expansion ratio HER of at least 30%.

Abstract: A method for producing a steel sheet having a microstructure including 71% to 91% martensite and bainite, 9% to 13% retained austenite, and at most 20% ferrite is provided. The method includes providing a cold-rolled steel sheet including, in weight percent: 0.13%?C?0.22%, 1.2%?Si?2.3%, 0.02%?Al?1.0%, with 1.25%?Si+Al?2.35%, 2.4%?Mn?3%, Ti?0.05%, Nb?0.05% and a remainder of Fe and unavoidable impurities, annealing the steel sheet to obtain 80% to 100% austenite and 0% to 20% ferrite, quenching the steel sheet at a cooling rate between 20° C./s and 50° C./s to a quenching temperature between 240° C. and 310° C., heating the steel sheet to a partitioning temperature between 400° C. and 465° C. and maintaining the steel sheet at the partitioning temperature for 50 to 250 seconds, then immediately cooling the sheet to room temperature. Steel sheets are also provided.

Abstract: A method for producing a high strength coated steel sheet having an improved ductility and an improved formability, the chemical composition of the steel containing: 0.13%?C?0.22%, 1.9%?Si?2.3%, 2.4%?Mn?3%, Al?0.5%, Ti<0.05%, Nb<0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

Abstract: A method is for producing a high strength coated steel sheet having a yield stress YS>800 MPa, a tensile strength TS>1180 MPa, and improved formability and ductility. The steel contains: 15%?C?0.25%, 1.2%?Si?1.8%, 2%?Mn?2.4%, 0.1%?Cr?0.25%, Al?0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature higher than Ac3 and lower than 1000° C. for a time of more than 30 s, then quenched by cooling it to a quenching temperature QT between 250° C. and 350° C., to obtain a structure consisting of at least 60% of martensite and a sufficient austenite content such that the final structure contains 3% to 15% of residual austenite and 85% to 97% of martensite and bainite without ferrite, then heated to a partitioning temperature PT between 430° C. and 480° C. and maintained at this temperature for a partitioning time Pt between 10 s and 90 s, then hot dip coated and cooled to the room temperature.

Abstract: A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%?C?0.22%, 1.9%?Si?2.3%, 2.4%?Mn?3%, Al?0.5%, Ti?0.05%, Nb?0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000° C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200° C. and 280° C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430° C. and 490° C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.