EFFECTS OF STRESS RATIO AND FREQUENCY ON CORROSION FATIGUE CRACK GROWTH IN LOW ALLOY STEEL
应力比和频率对低合金钢腐蚀疲劳裂纹扩展机理的影响

Based on theoretical analysis about local strain, strain rate and dissolving rateat crack tip, the corrosion fatigue crack growth rate of steels ZG20SiMn and SM50B-Zc infresh water and 3.5%NaCl respectively were measured experimentally, and the pH and elec-trode potential within crack were also measured continously along with crack propagating.The hydrogen concentration of materials in the crack tip region were measured. It showedthat the increase of corrosion fatigue crack growth rate, caused by both the decreasing fre-quency and the raising stress ratio, was mainly accelerated by hydrogen embrittlement.