钛合金及其油井管耐蚀性能研究进展

Research Progress on Corrosion Resistance of Titanium Alloy and Its Oil Country Tubular Goods

摘要:

综述了油井管现状、钛合金组织与力学性能,重点探讨了钛合金作为油井管的耐蚀性能、影响因素与耐蚀机理,并对第一性原理计算在钛合金管材成分设计与界面腐蚀特征中的应用进行了概述。研究发现,钛合金管材具有较强的抗硫化物应力开裂(SSC)性能,在高温高压(HTHP)油气田的工况条件下具有极低的腐蚀速率,对孔蚀、缝隙腐蚀、接触腐蚀以及氢脆等也具有高的抵抗力; Ti-6Al-4V(TC4)合金表面的钝化膜在含H_2S腐蚀环境中更易遭到破坏,其稳定性会因温度变化与其他元素介入而发生变化,抗腐蚀性能也会随之发生改变。

关键词:钛合金;油井管;腐蚀;数值模拟;界面腐蚀

Abstract:

The present situation of oil country tubular goods( OCTG),titanium alloy microstructure and mechanical properties were reviewd,corrosion resisting property of titanium alloy as OCTG,influence factors and corrosion resistant mechanism were focused on,and the first-principles calculation in the composition design of the titanium alloy OCTG and the application of the interface corrosion characteristics were introduced. It is found that titanium alloy OCTG has strong resistance to sulfide stress cracking( SSC),the very low corrosion rate under the working conditions of high temperature and high pressure( HTHP) oil and gas field,and the strong resistance to pitting corrosion,crevice corrosion,contact corrosion and hydrogen embrittlement. The passivation film on Ti-6 Al-4 V( TC4) titanium alloy is more likely to be damaged in H_2S corrosion environment,the stability of titanium passivation film will change due to temperature change and other elements intervention,and then corrosion resistance will be different accordingly.

Key words:titanium alloy;oil country tubular goods;corrosion;numerical modelling;interfacial corrosion