Test pipeline steel (/%： 0.04-0.05C

0.20-0.24Si

1.80-1.88Mn

0.010-0.012P

0.004-0.005S

0.27-0.30Cr

0.42-0.46Ni

0.24-0.28Mo

0.20Cu

0.005V

0-0.017Y

0.0031 -0.0053O) is melt by a 10 kg induction furnace and rolled to test bar. The effect of rare earth yttrium on corrosion resistance of pipeline steel in simulated seawater (3.5% NaCl) is studied by using scanning electron microscope and energy spectrum analysis

electrochemical techniques and thermodynamics calculated method. Results show that the rare earth has modification effect on inclusions in steel to modify the large scale and spinel structure Al

2

O

3

inclusions to small spheroidal rare earth compound inclusions； therefore it is favorable to form the continuous and compact inner rust layer

decrease the pitting corrosion source and increase th

e corrosion resistance of steel.