对新型ADB610低碳贝氏体钢进行了焊条电弧焊接, 采用柔度法得到了焊接接头裂纹长度(a)和循环寿命(N)的关系曲线; 根据a-N曲线采用一次七点递增多项式拟合方法计算了母材、热影响区和焊缝的疲劳裂纹扩展速率(da/dN), 并和应力强度因子范围(ΔK)数据进行回归拟合, 得到了以Paris公式表达的焊接接头各区域的疲劳裂纹扩展速率表达式。结果表明: 在疲劳裂纹扩展的初期和中期, 焊缝的裂纹扩展速率最慢, 母材区裂纹扩展速率最快; 在裂纹扩展末期, 三区域的裂纹扩展速率相近。

The ADB610 steel was welded using shielded metal arc welding method, and the fatigue crack length (a) vs. fatigue life (N) curves was measured by using crack compliance method. Base on a-N curves, the fatigue crack propagation rates of each sample from base material (BM), heat affected zone (HAZ) and weld seam (WS) were calculated by fitting a polynomial to a strip of 7 data points and linear regression fitted with stress intensity factor range (ΔK). The formula based on Paris of (da/dN) and (ΔK) was obtained. The results show that the fatigue crack growth rate in BM was higher than that in HAZ and WS, and that in WS was the slowest during the early and middle stage of crack growth; during the last stage of crack growth the difference of fatigue crack growth rate in three regions was not significant.