A hot rolled steel sheet and a method of manufacturing thereof

Abstract

A hot rolled steel sheet having a composition comprising of the following elements, 0.03% ≤ Carbon ≤ 0.07 %,0.8 % ≤ Manganese ≤ 1.3%, 0.01% ≤ Aluminum ≤ 0.07 %, 0.01% ≤ Niobium ≤ 0.07%, 0.05 % ≤ Titanium ≤ 0.15%, 0.0005% ≤ Calcium ≤ 0.005%, 0% ≤ Phosphorus ≤ 0.03 %, 0 % ≤ Sulfur ≤ 0.015 %, 0 % ≤ Nitrogen ≤ 0.02%, 0.001% ≤ Silicon ≤ 0.09%, 0% ≤ Chromium ≤ 0.2%, 0.03% ≤ Copper ≤ 0.25%, 0% ≤ Nickel ≤ 0.2%, 0% ≤ Molybdenum ≤ 0.2%, 0% ≤ Vanadium ≤ 0.1%, 0 % ≤ Boron ≤ 0.003%, 0 % ≤ Magnesium ≤ 0.010%, 0% ≤ Cerium≤ 0.1%, 0% ≤ Zirconium ≤ 0.010%,,the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 40% to 75% Bainite, 25% to 60% Ferrite, Pearlite from 0% to 2% and Martensite-Residual Islands from 0% to 2% wherein the said hot rolled steel sheet has an inclusion density of 200 inclusions per square micro-meter, the inclusions having a size of 2 microns or more being 15% or less of the total number of inclusions.

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