外加电位对X80钢在南雄土壤模拟溶液中应力腐蚀行为的影响

Effect of Applied Potentials on Stress Corrosion Cracking of X80 Steel in Simulated Nanxiong Soil Solution

采用动电位极化技术、慢应变速率拉伸(SSRT)试验和SEM形貌分析等方法,研究了外加电位对X80钢在南雄土壤模拟溶液中的应力腐蚀破裂(SCC)行为的影响。结果表明,在不同外加电位下,X80钢在土壤模拟溶液中呈现出不同的SCC敏感性。在-550mV(SCE,下同)阳极电位下,X80钢的阳极溶解抑制了其SCC的发生;在自腐蚀电位Ecorr(约-720mV)下,X80钢SCC行为呈现出受阳极溶解和氢脆混合控制的机制;在-850mV阴极电位下,阴极保护抑制了X80钢SCC的发生;而在-1 000mV和-1 150mV阴极电位下,氢脆在X80钢SCC过程中占重要作用。

Stress corrosion cracking （SCC） of X80 steel in a simulated solution of the soil environmenl in Nanxiong of China was investigated by methods of potentiodynamic polarization, slow strain rate test （SSRT） and fracture morphology characterized by scanning electron microscopy （SEM）. The results show that X80 steel has differenl SCC suscepbility of different applied potentials in the soil simulated solution. The SCC behavior of X80 steel is restrained by its anodic disslution at anodic potential of -550 mV. The SCC behavior was controlled by the combined effect of anodic disslution （AD） and hydrogen embrittlement （HE） at the Ecorr of - 720 mV. With the applied cathodic potential of - 850 mV, the SCC was restricted by the cathodic protection effect. However, when the cathodic potentials of - 1 000 mV and - 1 150 mV were applied, HE played a more important role in affecting SCC occurrence.