Through the analysis of the performance requirements of high weathering steels

the composition design of test steel is based on Cu and P

with the addition of a small amount of Cr and Ni. Combined with the corresponding rolling and coiling process

and a 355 strength grade high weathering steels was successfully developed. The mechanical properties of test steels were tested

and the corrosion resistance was predicted according to its composition design. The corrosion rate and rust layer composition of Q355GNH test steels and Q345B steels were evaluated and observed by the method of laboratory accelerated corrosion test. The results show that the various mechanical properties and low temperature (-40℃) impact toughness of test steels far meet the re

quirements of national standard; The atmospheric corrosion resistance index of test steels is 7. 13

far exceeding the standard requirements. The average relative corrosion rate of Q355GNH test steel is only 47.40% of the comparative Q345B steel under the same corrosion conditions. Compared with Q345B steel

a flocculent

dense rust layer is formed on the surface of Q355GNH test steel after alternate immersion test

and it is observed that the content of stable phase α-FeOOH with protective effect is relatively high in the rust laye（α-FeOOH ： 18. 2%、Fe

3

O

4

: 9. 1% )

which makes the structure of the rust layer play a protective role on the matrix.