| abstract |
A hot rolled steel product having a composition comprising in percentage by weight:0.06%≤C≤0.18 %,0.01%≤Ni≤0.6 %, 0.001%≤Cu≤2%,0.001%≤Cr≤2%,0.001%≤Si≤0.8 %, 0%≤N≤0.008%, 0%≤P≤0.03%, 0%≤S≤0.03%,0.001%≤Mo≤0.5%,0.001%≤Nb≤0.1%, 0.001%≤V≤0.5%,0.001%≤Ti≤0.1% and one or more following optional elements 0.2 % ≤Mn ≤ 2%, 0 005% ≤ Al ≤ 0.1 %,0 % ≤ B ≤ 0.003%,0% ≤ Ca≤ 0.01%,0 % ≤ Mg ≦ 0.010% the remainder composition being composed of iron and unavoidable impurities caused by processing, such product having a tertiary scale layer comprising, in area fraction, a total amount of at least 50% of magnetite and ferrite wherein ferrite is at least 25%, 0% to 50 % of wustite, and 0% to 10% of hematite, such scale layer having a thickness between 5 microns and 40 microns. |