Influencing Factors of 1Cr13 SSCC for Oil & Gas Wellhead
With the exploration of oil-gas field developing, more and more oil-gas well contain H2S, hydrogen sulfide stress corrosion has serious effect on production and restrict oil field development. With the applications of 1Cr13 steel in oil & gas wellhead, it is urgent to research hydrogen sulfide stress corrosion cracking (SSCC) properties in high-strength under the simulation condition of production. The tensile test under constant load and slow strain rate test (SSRT) were adopted to analyze the behaviors of 1Cr13 steel with orthogonal test under saturated H2S solution which included carbon dioxide under a partial pressure and its sample fracture was observed with SEM (Scanning Electron Microscope). Constant load tensile test is one of the first recognized by NACE to assess the performance of metallic materials against SSC approach under tensile stress in the aqueous solution which was in low pH value and H2S was saturated. Through the research above the mechanism of stress corrosion and the environmental factors that influence stress corrosion were investigated. The experimental results shown that the effects of environmental factors on SCC (Stress Corrosion Cracking) sensitivity of materials are in the following order: temperature effect > solution pH effect > chloride ion concentration effect, and 1Cr13 material has a better corrosion resistance for H2S and CO2 conditions under a certain stress so it can be proposed as the material of value for oil & gas wellhead. Through SEM it can be seen that the fracture is belonged to brittle fracture. The lattice bonding force is destroyed by hydrogen into the material that gathered in the certain crystal face and the material transform from plastic to brittleness, the material is failed, and SCC occurred.
Yansheng Yin and Xin Wang
J. F. Pei et al., "Influencing Factors of 1Cr13 SSCC for Oil & Gas Wellhead", Advanced Materials Research, Vols. 79-82, pp. 1005-1008, 2009