摘要
研究了4130X钢在硫化氢(H2S)腐蚀介质中的疲劳裂纹扩展速率da/dN。应用改进型WOL试样,采用符合实际工况的中等浓度200×10-6的H2S溶液、0.0067 Hz的超低周频率,在自行改造的专用低周腐蚀疲劳试验机上进行了试验。在恒定疲劳载荷谱作用下,采用三保险的位移测量装置,利用计算机自动采集系统,时时采集载荷及位移,用柔度方程求解试样瞬时裂纹长度。克服了表面直读法在腐蚀环境中不易观测裂纹长度的缺点,对所有试验数据,以KISCC为分界线,用Paris公式进行两段式拟合,给出了da/dN—ΔK的数学表达式,为确定气瓶的临界裂纹尺寸提供了试验依据。文中还将本试验结果与相关文献中其它硫化氢环境及空气中的疲劳裂纹扩展速率结果进行了比较。结果表明:H2S环境中裂纹扩展速率远大于空气中结果,不同环境、频率对da/dN有较大影响。
The fatigue crack growth rate （FCGR） of 4130X steel in H2S environment is researched in this paper. By using modified WOL specimens, under a low frequency 0. 0067 Hz and in the moderate concentration （200 × 10^-6） sulfured hydrogen solution; the tests were accomplished on a modified low- frequency corrosion fatigue machine. Under a constant fatigue load range, using three extensometers, the load and the displacement were measured by computer instantaneously, and the crack length was calculated by compliance equation. Two equations of FCGR, divided by the value of KISCC, were found according to the experimental data by Paris expression, which gave us the experimental bases to confirm the critical crack size of the vessel. Compared with other FCGRs in H2S or air, which were reported by others, the result showed that FCGRs in H2S environment were much higher than those in air, concentration and frequency affect da/dN very much.
出处
《压力容器》
北大核心
2006年第2期12-18,共7页
Pressure Vessel Technology
