The invention deals with a hot rolled steel having a composition comprising the following elements, expressed in percentage by weight: 15 % ≤ Nickel ≤ 25 % 6 % ≤ Cobalt ≤ 12% 2% ≤ Molybdenum ≤ 6% 0.1 % ≤ Titanium ≤ 1% 0.0001% ≤ Carbon ≤ 0.03% 0.002 % ≤ Phosphorus ≤ 0.02 % 0 % ≤ Sulfur ≤ 0.005 %. 0 % ≤ Nitrogen ≤ 0.01% and can contain one or more of the following optional elements 0% ≤ Aluminum ≤ 0.1 % 0% ≤ Niobium ≤ 0.1% 0% ≤ Vanadium ≤ 0.3% 0% ≤ Copper ≤ 0.5% 0% ≤ Chromium ≤ 0.5% the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 20% to 40% Tempered Martensite, at least 60% of Reverted Austenite and inter-metallic compounds of Molybdenum, Titanium and Nickel.