Abstract: A method for producing a steel part and corresponding steel part includes casting a steel having a composition comprising: 0.10%?C?0.35%, 0.8%?Si?2.0%, 1.8%?Mn?2.5%, P?0.1%, 0%?S?0.4%, 0%?Al?1.0%, N?0.015%, 0%?Mo?0.4%, 0.02%?Nb?0.08%, 0.02%?Ti?0.05%, 0.001%?B?0.005%, 0.5%?Cr?1.8%, 0%?V?0.5%, 0%?Ni?0.5%, to obtain a semi-product, hot rolling the semi-product at a hot rolling starting temperature higher than 1000° C. and cooling the product through air to room temperature to obtain a hot rolled steel part having a microstructure consisting of 70% to 90% of bainite, 5% to 25% of M/A compounds and at most 25% of martensite. The bainite and the M/A compounds contain retained austenite such that the total content of retained austenite in the steel is comprised between 5% and 25%, the carbon content of the retained austenite being comprised between 0.8% and 1.5%.

Abstract: The present invention provides a part having a composition including, with the contents being expressed in weight-percent, 0.10?C?0.30, 1.6?Mn?2.1, 0.5?Cr?1.7, 0.5?Si?1.0, 0.065?Nb?0.15, 0.0010?B?0.0050, 0.0010?N?0.0130, 0?Al?0.060, 0?Mo?1.00, 0?Ni?1.0, 0.01?Ti?0.07, 0?V?0.3, 0?P?0.050, 0.01?S?0.1, 0?Cu?0.5, 0?Sn?0.1. A balance of the composition includes iron and unavoidable impurities resulting from the production method. The microstructure includes, in surface proportions, from 100% to 70% bainite, less than 30% residual austenite, and less than 5% ferrite. A manufacturing method is also provided.

Abstract: Method for producing a steel part including by weight: 0.05%?C?0.15%, 0.01%?Si?1%, 1.2%?Mn?2%, 0.1%?Cr?2%, 0.001?Al?0.1%, 0.003%?N?0.01%, 0?S?0.015%, 0?P?0.015%, 0%?Ni?1%, 0%?B?0.01%, 0%?Mo?1%, 0%?Ti?0.04%, 0%?Nb?0.1%, 0?V?0.5% the remainder consisting of iron and unavoidable impurities, annealing this semi-finished product at an annealing temperature strictly lower than the Ac1 temperature of the steel; cooling it down to room temperature; cold forming the semi-finished product into a cold formed product; subjecting the cold formed product to a heat treatment comprising heating the cold formed product to a heat treatment temperature greater than or equal to the full austenitisation temperature Ac3 of the steel; and quenching to room temperature; optionally reheating the product at a holding temperature from 180° C. to 400° C. for a time from 15 minutes to 2 hours.

Abstract: A steel for forging mechanical parts including of the following elements 0.04%?C?0.28%; 1.2%?Mn?2.2%; 0.3%?Si?1.2%; 0.5%?Cr?1.5%; 0.01%?Ni?1%; 0%?S?0.06%; 0%?P?0.02%; 0%?N?0.015%; 0%?Al?0.1%; 0.03%?Mo?0.5%; 0%?Cu?0.5%; 0.04%?Nb?0.15%; 0.01%?Ti?0.1%; 0%?V?0.5%; 0.0015%?B?0.004%; the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel having microstructure including in area fraction, 55% to 85% of Martensite, 20% to 45% of Auto-tempered Martensite, 0 to 10% Residual Austenite and, wherein cumulated amounts of Auto-tempered martensite and martensite is at least 90%.

Abstract: Method for producing a steel part comprising providing a semi-finished product made of a steel comprising, by weight: 0.35%?C?0.60%; 0.15%?Si?0.5%; 0.8%?Mn?2.0%; 0.0003%?B?0.01%; 0.003%?Mo?1.0%; 1.0%?Cr?2.0%; 0.01%?Ti?0.04%; 0.003%?N?0.01%; S?0.015%; P?0.015%; 0.01%?Ni?1.0%; 0.01%?Nb?0.1%; optionally 0?Al?0.1%; 0?V?0.5%; and the remainder consisting of iron and unavoidable impurities. The method further including annealing this semi-finished product at a temperature strictly lower than the Ac1 temperature of the steel; cold forming the semi-finished product into a cold formed product; subjecting the cold formed product to a heat treatment comprising heating the cold formed product to a temperature greater than or equal to the Ac3 temperature of the steel; and holding the product at a holding temperature comprised between 300° C. and 400° C. for a time comprised between 15 minutes and 2 hours.

Abstract: A method for producing a steel part and corresponding steel part includes casting a steel having a composition comprising: 0.10%?C?0.35%, 0.8%?Si?2.0%, 1.8%?Mn?2.5%, P?0.1%, 0%?S?0.4%, 0%?Al?1.0%, N?0.015%, 0%?Mo?0.4%, 0.02%?Nb?0.08%, 0.02%?Ti?0.05%, 0.001%?B?0.005%, 0.5%?Cr?1.8%, 0%?V?0.5%, 0%?Ni?0.5%, to obtain a semi-product, hot rolling the semi-product at a hot rolling starting temperature higher than 1000° C. and cooling the product through air to room temperature to obtain a hot rolled steel part having a microstructure consisting of 70% to 90% of bainite, 5% to 25% of M/A compounds and at most 25% of martensite. The bainite and the M/A compounds contain retained austenite such that the total content of retained austenite in the steel is comprised between 5% and 25%, the carbon content of the retained austenite being comprised between 0.8% and 1.5%.

Abstract: The present invention provides a part having a composition including, with the contents being expressed in weight-percent, 0.10?C?0.30, 1.6?Mn?2.1, 0.5?Cr?1.7, 0.5?Si?1.0, 0.065?Nb?0.15, 0.0010?B?0.0050, 0.0010?N?0.0130, 0?Al?0.060, 0?Mo?1.00, 0?Ni?1.0, 0.01?Ti?0.07, 0?V?0.3, 0?P?0.050, 0.01?S?0.1, 0?Cu?0.5, 0?Sn?0.1. A balance of the composition includes iron and unavoidable impurities resulting from the production method. The microstructure includes, in surface proportions, from 100% to 70% bainite, less than 30% residual austenite, and less than 5% ferrite. A manufacturing method is also provided.

Abstract: The steel according to the invention is characterized in that, in order to keep its weight content of molybdenum below 0.45%, its chemical composition, besides the iron and the inevitable residual impurities that result from the smelting of the steel, corresponds to the following analysis, given as percentages by weight: 0.3?C %?0.5 0.20?Mo %<0.45 0.4?Mn %?1.0 0.4?Cr %?2.0 0.04?Ni %?0.8 0.02?Nb %?0.045 0.03?V %?0.30 0.02?Ti %?0.05, with Ti>3.5 N 0.003?B %?0.005% S %?0.015 P %?0.015, and optionally 0.05?Si %?0.20; Al %?0.05 and N %?0.015. By cold forming a hot-rolled wire rod resulting from continuous casting, it is possible to obtain, after heat treatment, “ready-to-use” coined parts, such as cap screws for example for the automotive industry, that offer a tensile strength from 1200 to more than 1500 MPa while having a good hydrogen embrittlement resistance, and this with a specially controlled “raw material” production cost.

Abstract: The steel according to the invention is characterized in that, in order to keep its weight content of molybdenum below 0.45%, its chemical composition, besides the iron and the inevitable residual impurities that result from the smelting of the steel, corresponds to the following analysis, given as percentages by weight: 0.3?C %?0.5 0.20?Mo %<0.45 0.4?Mn %?1.0 0.4?Cr %?2.0 0.04?Ni %?0.8 0.02?Nb %?0.045 0.03?V %?0.30 0.02?Ti %?0.05, with Ti>3.5 N 0.003?B %?0.005% S %?0.015 P %?0.015, and optionally 0.05?Si %?0.20; Al %?0.05 and N %?0.015. By cold forming a hot-rolled wire rod resulting from continuous casting, it is possible to obtain, after heat treatment, “ready-to-use” coined parts, such as cap screws for example for the automotive industry, that offer a tensile strength from 1200 to more than 1500 MPa while having a good hydrogen embrittlement resistance, and this with a specially controlled “raw material” production cost.

Abstract: A ready-for-use low-carbon steel mechanical component, like wheel swivel joints of terrestrial vehicles, pins, shafts, suspension bars, links . . . with elevated characteristics obtained by a hot or cold plastic transformation of a laminated long steel product (wire or rod) without any further heat treatment, the chemical composition of said steel complies with the following analysis, given in percentages by weight, based on the iron: C?0.15%; 0.04%?Nb?0.10%; 0.001%?B?0.005%; 0.15%?Mo?0.35%; 1.3%?Mn?2.0%; 0.15%?Si?1.30%; 0.01%?Al?0.08% and N?0.015% with Ti?3.5×% N and said long steel product is obtained from a semi-finished product coming from the continuous casting and hot-rolled in the austenitic range to obtain a bainitic or essentially bainitic structure, and worked by a cold or hot plastic transformation into its final shape, exhibiting a tensile strength at break greater than 800 MPa. The invention is particularly directed to applications of stamping or cold forging or hot forging.