Abstract: A coated steel sheet and press hardened steel part having a composition including, by weight percent: C 0.15-0.25%, Mn 0.5-1.8%, Si 0.1-1.25%, Al 0.01-0.1%, Cr 0.1-1.0%, Ti 0.01-0.1%, B 0.001-0.004%, P?0.020%, S?0.010%, N?0.010% the remainder of the composition being iron and unavoidable impurities resulting from the smelting. The press hardened steel part includes a bulk having a microstructure including, in surface fraction, more than 95% of martensite and less than 5% of bainite, a coating layer at the surface of the steel part, a ferritic interdiffusion layer between the coating layer and the bulk, and a ratio between the ferritic grain width in the interdiffusion layer GWint over prior austenite grain size in the bulk PAGSbulk, satisfying following equation (GWint/PAGSbulk)?1?30%.

Abstract: A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%?C?0.22%, 3.5%?Mn<4.2%, 0.001%?Si?1.5%, 0.020%?Al?0.9%, 0.001%?Cr?1%, 0.001%?Mo?0.3%, 0.001%?Ti?0.040%, 0.0003%?B?0.004%, 0.001%?Nb?0.060%, 0.001%?N?0.009%, 0.0005%?S?0.003%, 0.001%?P?0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10{circumflex over (?)}7/mm2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

Abstract: A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%?C?0.22%, 3.5%?Mn<4.2%, 0.001%?Si?1.5%, 0.020%?Al?0.9%, 0.001%?Cr?1%, 0.001%?Mo?0.3%, 0.001%?Ti?0.040%, 0.0003%?B?0.004%, 0.001%?Nb?0.060%, 0.001%?N?0.009%, 0.0005%?S?0.003%, 0.001%?P?0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10{circumflex over (?)}7/mm2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

Abstract: A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%?C?0.22%, 3.5%?Mn<4.2%, 0.001%?Si?1.5%, 0.020%?Al?0.9%, 0.001%?Cr?1%, 0.001%?Mo?0.3%, 0.001%?Ti?0.040%, 0.0003%?B?0.004%, 0.001%?Nb?0.060%, 0.001%?N?0.009%, 0.0005%?S?0.003%, 0.001%?P?0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10{circumflex over (?)}7/mm2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

Abstract: A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%?C%?0.22%, 3.5%?Mn<4.2%, 0.001%?Si%?1.5%, 0.020%?Al?0.9%, 0.001%?Cr?1%, 0.001%?Mo?0.3%, 0.001%?Ti?0.040%, 0.0003%?B?0.004%, 0.001%?Nb?0.060%, 0.001%?N?0.009%, 0.0005%?S?0.003%, 0.001%?P?0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10?7/mm2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.