More lowcharred steel

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The invention relates to low alloy steels for high strength parts : etc screws, drive - and chassis parts. The specificity of the steel is a high resistance to hydrogen brittleness/stress corrosion fatigue fracture/proposed wherein minimum tensile strength. The steel will allow the quenching in water. The steel contains silicon, manganese, chromium, aluminum, titanium and at least one element of alkaline earth metals and is characterized in, that the contents of these alloying elements are as follows C=0.15 - 0.6 Si=0.25 - 6 Mn=0.2 - 2 Cr=0.15 - 1 Al=0.05 - 0.3 Ti=0.015 - 0.1 Ca=0.005 - 0.03 or/and/or=0.008 - 0.08 mg=0.002 - 0.02 and (+ of Ba to SR) wherein summary ratio between minimum carbon content and silicon manganese and chromium content summary to maximum, the discussed an absolute resistance to hydrogen embrittlement guaranteed, the following minimum tensile strength is a function of : (of Mnmax. 2 x of Cr +max. ) ≤ 1.0 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 1400 mpa (of Mnmax. 2 x of Cr +max. ) ≤ 1.3 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 1300 mpa (of Mnmax. 2 x of Cr +max. ) ≤ 1.8 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 1200 mpa (of Mnmax. 2 x of Cr +max. ) ≤ 2.4 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 1100 mpa (of Mnmax. 2 x of Cr +max. ) ≤ 3.2 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 1000 mpa (of Mnmax. 2 x of Cr +max. ) ≤ 5.0 x (of Siminutes + 4 × Cminutes ) wherein strength ≥ 800 mpa the steel may additionally include B=0.001 - 0.01%, Zr or/and/or nitrogen and/or 0.01 - 0.05%==0.01 - 0.15% rare earth elements and p=0.04 - 0.15.