Abstract: A method for making a tempered and coated steel sheet having a composition containing the following elements, expressed in percentage by weight: 0.17%?carbon?0.25%, 1.8%?manganese?2.3%, 0.5%?silicon?2.0%, 0.03%?aluminum?1.2%, sulphur?0.03%, phosphorus?0.03%, the remainder composition being composed of iron and unavoidable impurities caused by processing. The composition may also contain one or more of the following elements chromium?0.4%, molybdenum?0.3%, niobium?0.04%, titanium?0.1%.

Abstract: A tempered and coated steel sheet having a composition containing the following elements, expressed in percentage by weight: 0.17%?carbon?0.25%, 1.8%?manganese?2.3%, 0.5%?silicon?2.0%, 0.03%?aluminum?1.2%, sulphur?0.03%, phosphorus?0.03%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet containing in area fraction, 3 to 20% residual austenite, at least 15% of ferrite, 40 to 85% tempered bainite and a minimum of 5% of tempered martensite, wherein cumulated amounts of tempered martensite and residual austenite is between 10 and 30%. The composition may also contain one or more of the following elements chromium?0.4%, molybdenum?0.3%, niobium?0.04%, titanium?0.1%. Methods of manufacturing and use of the tempered and coated steel sheets are also described.

Abstract: A tempered and coated steel sheet having a composition containing the following elements, expressed in percentage by weight: 0.17%?carbon?0.25%, 1.8%?manganese?2.3%, 0.5%?silicon?2.0%, 0.03%?aluminum?1.2%, sulphur?0.03%, phosphorus?0.03%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet containing in area fraction, 4 to 20% residual austenite, 0 to 15% of ferrite, 40 to 85% tempered bainite and a minimum of 5% of tempered martensite, wherein the cumulated amounts of tempered martensite and residual austenite is between 10 and 30%. The composition may also contain one or more of the following elements: chromium?0.4%, molybdenum?0.3%, niobium?0.04%, titanium?0.1%. Manufacturing methods and use of tempered and coated steel sheet for making vehicle parts are also described.

Abstract: A cold rolled steel sheet, the steel containing, in weight percentage, 0.19%?carbon?0.24%, 1.9%?manganese?2.2%, 1.4%?silicon?1.6%, 0.01%?aluminum?0.06%, 0.2%?chromium?0.5%, phosphorus?0.02%, sulfur?0.003%, the balance including iron and unavoidable impurities, the steel sheet having a microstructure containing 5% to 15% of tempered martensite, 10% to 15% of residual austenite, the balance containing bainite, bainite content being at least 70%, is described. Also described is a manufacturing method and with use of such grade for making vehicle parts.

Abstract: A tempered and coated steel sheet having a composition containing the following elements, expressed in percentage by weight: 0.17%?carbon?0.25%, 1.8%?manganese?2.3%, 0.5%?silicon?2.0%, 0.03%?aluminum?1.2%, sulphur?0.03%, phosphorus?0.03%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet containing in area fraction, 3 to 20% residual austenite, at least 15% of ferrite, 40 to 85% tempered bainite and a minimum of 5% of tempered martensite, wherein cumulated amounts of tempered martensite and residual austenite is between 10 and 30%. The composition may also contain one or more of the following elements chromium?0.4%, molybdenum?0.3%, niobium?0.04%, titanium?0.1%. Methods of manufacturing and use of the tempered and coated steel sheets are also described.

Abstract: A cold rolled steel sheet, the steel containing, in weight percentage, 0.19%?carbon?0.24%, 1.9%?manganese?2.2%, 1.4%?silicon?1.6%, 0.01%?aluminum?0.06%, 0.2%?chromium?0.5%, phosphorus?0.02%, sulfur?0.003%, the balance including iron and unavoidable impurities, the steel sheet having a microstructure containing 5% to 15% of tempered martensite, 10% to 15% of residual austenite, the balance containing bainite, bainite content being at least 70%, is described. Also described is a manufacturing method and with use of such grade for making vehicle parts.

Abstract: A tempered and coated steel sheet having a composition containing the following elements, expressed in percentage by weight: 0.17%?carbon?0.25%, 1.8%?manganese?2.3%, 0.5%?silicon?2.0%, 0.03%?aluminum?1.2%, sulphur?0.03%, phosphorus?0.03%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet containing in area fraction, 4 to 20% residual austenite, 0 to 15% of ferrite, 40 to 85% tempered bainite and a minimum of 5% of tempered martensite, wherein the cumulated amounts of tempered martensite and residual austenite is between 10 and 30%. The composition may also contain one or more of the following elements: chromium?0.4%, molybdenum?0.3%, niobium?0.04%, titanium?0.1%. Manufacturing methods and use of tempered and coated steel sheet for making vehicle parts are also described.