Effects of cathodic protection for scouring corrosion of X60, AISI321, 316L and F5 materials in 10% H_2SO_4+15% corundum sand(60~#) acidic liquid/solid phases flowing medium were investigated. It was found that cathodic protection efficiency was a function of flow velocity.
With regard to three main cracking forms in oil & gas pipelines, i.e. high pH SCC, near-neutral pH SCC and hydrogen induced cracking (HIC), it is discussed well on the mechanism of their occurence, occurrence conditions, and characteristics. The controlling factors of SCC, and HIC, such as the environmental solution, catholic protection, coating, temperature, corrosion products, stress and strain, materials etc.
As increase of development in pipeline system densely at badly natural circumstances areas, the needs of power source for catholic protection, the difficulty for installing anodes due to higher electric resistance of soil, the inconvenience for measuring due to desolation conditions and disturbance at the pipeline system dense areas, all these problems should be solved in applying catholic protection.
The paper introduces advances in catholic protection techniques and actual applications in power source, such as strip sacrifice anode, assistant anode, anode's bed resistance reducer and measuring methods etc. .
Based on the spreading and application condition ofarea cathod protection in Longdong oil area,the ar-ticle discusses the main factors which innuence theeffect of area cathode protection such as, cathodground bed, anode wire, pipe-network insulation,power supply facilities,maintaining and supervisionetc.