A Nb-V Microalloyed Cu-Bearing high strength weathering steel (/% : ≤ 0.12C

≤ 0. 40Si

≤ l. 40Mn

≤ 0.020P

≤ 0. 010S

0.40 ~0.45Cr

0.25 ~0.35Cu

≥ 0.020Al

0.02 ~0.03Nb

0.02 ~0.03V) with excellent comprehensive performance was developed by means of proper composition design and thermo mechanical control process ( TMCP)

and its corrosion resistance was studied. The microstructure of the high strength weathering steel was composed of ferrite

pearlite and bainite

whose tensile strength reached 697 MPa

yield ratio was 0. 73

elongation was 24. 6%

and -40 ℃  longitudinal impact energy was 70. 6 J. The results of salt spray test and periodical immersed corrosion test indicted that the corrosion resistance of test steel was obviously better than Q345B

and the test

steels rust layer after salt spray test by XRD analysis was mainly composed of Fe

3

O

4

α-FeO( OH) and -γ-FeO( OH)

and the relative content of Fe

3

O

4

increased with time

α-FeO(OH) changed slightly

γ-FeO(OH) decreased.