通过三点弯曲加载的表面裂纹试样研究了碳氮共渗、渗氮及调质几种不同热处理的(?)面裂纹疲劳扩展行为。试验证实:半椭圆表面疲劳裂纹的长轴(c)、短轴(α)与试样厚度(B)符合α/c+α/B=0.99±,,12的关系式。并且在我们的试验范围内(0.33≤α/c≤0.71;0.29≤α/B≤0.67),其长轴端应力强度因子可用简单的放学式进行计算:△K_c=A·△,(πc)/(1/2)·M_w.其中A≈0.5。由此大大简化了表面裂纹应力强度因子的计算。 The fatigue crack growth behavior of (?) Surface cracks under three different heat treatments was studied by three-point bending-loaded surface crack specimens with carbonitriding, nitriding and quenching. The results show that the major axis (c), minor axis (α) and thickness (B) of the semi-elliptical surface fatigue crack satisfy the relationship of α / c + α / B = 0.99 ± ,, 12. And in our experimental range (0.33≤α / c≤0.71; 0.29≤α / B≤0.67), the long-axis stress intensity factor at the long axis can be calculated by a simple school-like formula: △ K_c = A · △, (πc) / (1/2) · M_w, where A≈0.5. This greatly simplifies the calculation of surface crack stress intensity factor.