Salzgitter Flachstahl Gmbh

Sascha Kluge

Thomas Schulz

Joachim Schöttler

Andreas Wedemeier

Thorsten Michaelis

Peter Matthies

Tobias Klinkberg

Christian Meyer

Marion Calcagnotto

Sebastian Westhäuser

Marion Bechtold

A high-strength air-hardenable multiphase steel having minimal tensile strengths in a non air hardened state of 750 MPa and excellent processing properties, said steel comprising the following elements in % by weight: C&#x2265;0.075 to &#x2264;0.115; Si&#x2265;0.200 to &#x2264;0.300; Mn&#x2265;1.700 to &#x2264;2.300; Cr&#x2265;0.280 to &#x2264;0.4800; Al&#x2265;0.020 to &#x2264;0.060; N&#x2265;0.0020 to &#x2264;0.0120; S&#x2264;0.0050; Nb&#x2265;0.005 to &#x2264;0.050; Ti&#x2265;0.005 to &#x2264;0.050; B&#x2265;0.0005 to &#x2264;0.0060; Ca&#x2265;0.0005 to &#x2264;0.0060; Cu&#x2264;0.050; Ni&#x2264;0.050; remainder iron, including usual steel accompanying smelting related impurities, wherein for a widest possible process window during continuous annealing of hot rolled or cold rolled strips made from the steel a sum content of M+Si+Cr in the steel is a function of a thickness of the steel strips according to the following relationship: for strip thicknesses of up to 1.00 mm the sum content of M+Si+Cr is &#x2265;2.350 and &#x2264;2.500%, for strip thicknesses of over 1.00 to 2.00 mm the sum of Mn+Si+Cr is &#x2265;2.500 and &#x2264;2.950%, and for strip thicknesses of over 2.00 mm the sum of Mn+Si+Cr is &#x2265;2.950 and &#x2264;3.250%.

High-strength air-hardening multiphase steel having excellent processing properties, and method for manufacturing a strip of said steel

An ultra-high-strength air-hardenable multiphase steel having minimal tensile strengths in a non air hardened state of 950 MPa and excellent processing properties, includes the following elements in % by weight: C&#x2265;0.075 to &#x2264;0.115; Si&#x2265;0.400 to &#x2264;0.500; Mn&#x2265;1,900 to &#x2264;2,350; Cr&#x2265;0.200 to &#x2264;0.500; Al&#x2265;0.005 to &#x2264;0.060; N&#x2265;0.0020 to &#x2264;0.0120; S&#x2264;0.0030; Nb&#x2265;0.005 to &#x2264;0.060; Ti&#x2265;0.005 to &#x2264;0.060; B&#x2265;0.0005 to &#x2264;0.0030; Mo&#x2265;0.200 to &#x2264;0.300; Ca&#x2265;0.0005 to &#x2264;0.0060; Cu&#x2264;0.050; Ni&#x2264;0.050; remainder iron, including usual steel accompanying smelting related impurities, wherein for a widest possible process window during continuous annealing of hot rolled or cold rolled strips made from said steel a sum content of M+Si+Cr in said steel is a function of a thickness of the steel strips according to the following relationship: for strip thicknesses of up to 1.00 mm the sum content of M+Si+Cr is &#x2265;2.800 and &#x2264;3.000%, for strip thicknesses of over 1.00 to 2.00 mm the sum of Mn+Si+Cr is &#x2265;2.850 and &#x2264;3.100%, and for strip thicknesses of over 2.00 mm the sum of Mn+Si+Cr is &#x2265;2.900 and &#x2264;3.200%.

Ultra high-strength air-hardening multiphase steel having excellent processing properties, and method for manufacturing a strip of said steel

A high-strength multi-phase steel having minimum tensile strengths of 750 MPa and preferably having a dual-phase microstructure for a cold- or hot-rolled steel strip, in particular for lightweight vehicle construction is disclosed. The high-strength multi-phase steel has improved forming properties and a ratio of yield point to tensile strength of at most 73%. The high-strength multi-phase steel includes in mass %: C&#x2265;0.075 to &#x2264;0.105; Si&#x2265;0.600 to &#x2264;0.800; Mn&#x2265;1.000 to &#x2264;0.700; Cr&#x2265;0.100 to &#x2264;0.480; Al&#x2265;0.010 to &#x2264;0.060; N 0.0020&#x2264;0.0120; S&#x2264;0.0030; Nb&#x2265;0.005 to &#x2264;0.050; Ti&#x2265;0.0050 to &#x2264;0.050; B&#x2265;0.0005 to &#x2264;0.0040; Mo&#x2264;0.200; Cu&#x2264;0.040%; Ni&#x2264;0.040 % the remainder iron, including typical elements accompanying steel that are not mentioned above, which represent contamination resulting from smelting.

Micro-alloyed high-strength multi-phase steel containing silicon and having a minimum tensile strength of 750 MPA and improved properties and method for producing a strip from said steel

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Crimmitschau, Germany

Sascha Kluge