湿H2S环境中Q345R(HIC)的氢扩散规律及性能

Study on hydrogen diffusion law and performance of Q345R (HIC) in wet H2S environment

关键词:  湿H₂S环境  电化学渗氢  扩散氢  氢致硬化  氢损伤 

Key words:  wet H₂S environment  electrochemical hydrogen permeation  hydrogen diffusion  hydrogen induced hardening  hydrogen damage

摘要:

目的 模拟湿H₂S环境,采用氢渗透技术对Q345R(HIC)、SA516 Gr70N+316L复合钢板及316L在湿H₂S环境下的氢扩散规律及性能进行了研究。方法 采用电化学渗氢技术、拉伸、冲击试验和断口分析等方法,比较了不同pH值环境条件下材料中的原子氢浓度、有效扩散系数、强度、韧性和断口形貌等。结果 随着溶液pH值的降低,Q345R(HIC)中原子氢浓度(C₀)、氢有效扩散系数(D_eff)等均升高,pH值=3时,材料中的C₀可达17 mol/m³,D_eff可达2.22×10-10 m²/s。大量原子氢的渗入,使材料产生位错钉扎效果,发生了氢致硬化现象,材料内部出现了氢损伤白点特征,316L未发生氢损伤。结论 316L复合层可有效避免扩散氢对基材SA516 Gr70N或Q345R的损伤,对于Q345R(HIC),随着溶液pH值的降低,材料中渗入的原子氢越多,材料性能损伤越大。 

Abstract:

Objective Hydrogen diffusion law and performance of Q345R(HIC), SA516 Gr70N+316L composite steel plate and 316L in wet H₂S environment was studied by hydrogen osmosis technology. Methods The atomic hydrogen concentration, effective diffusion coefficient, strength, toughness and fracture morphology of the materials under different pH conditions were compared by methods of electrochemical hydrogenation technique, tensile test, impact test and fracture analysis. Results The results show that the concentration of atomic hydrogen C₀ and the effective diffusion coefficient Deff of hydrogen in Q345R(HIC) increase with the decrease of solution pH value. When pH=3, the C₀ and D_eff in Q345R(HIC) materials can reach 17 moL/m³ and 2.22×10-10 m²/s. The infiltration of large number of hydrogen atoms make the materials produce dislocation pin effect. Hydrogen hardening occurred, and white spots of hydrogen damage appeared in the material. No hydrogen damage occurred in 316L. Conclusion The 316L composite layer can effectively avoid the damage of the diffusion hydrogen on the substrate SA516 Gr70N or Q345R. For Q345R (HIC), with the decrease of solution pH value, the more atomic hydrogen infiltrate into the material, the greater the damage of the material performance is.