目的 尝试采用新型微裂纹铬工艺或者引入缓冲层来实现镀铬层抗疲劳性能的改善。方法 分别采用标准硬铬、自研微裂纹铬工艺对30CrMnSiA高强钢进行处理，通过旋转弯曲疲劳试验评价了两种镀铬工艺对其疲劳性能的影响。同时，对比了镀铜预处理的作用，利用FESEM分析了断口形貌。结果 相比于硬铬镀层，自研微裂纹铬镀层表面微裂纹浅而细、数目更多，密度高达1020 条/cm，且裂纹未贯穿镀层，呈层状分布。在850 MPa应力下，30 μm厚的硬铬镀层会使30CrMnSiA钢的中值疲劳寿命下降48%左右，疲劳断口呈多源区特征。而相同厚度的自研微裂纹铬镀层仅使基体的疲劳寿命下降了23%，疲劳试验后镀层上未发现明显裂纹、裂纹呈多向性扩展。结论 自研微裂纹铬工艺处理的30CrMnSiA钢，其抗疲劳性能明显好于硬铬处理试样。若在基体/镀铬层之间引入镀铜过渡层，可有效地减少直达金属基体的裂纹数目，30CrMnSiA钢的疲劳性能得到明显改善，中值疲劳寿命几乎接近于基体。

Chromium plating is widely used for surface strengthening of high-strength steel, but it will damage the fatigue strength of the matrix. This paper attempted to improve the fatigue resistance of chromium plating by using a new micro-crack chromium technique or introducing buffer layer. 30CrMnSiA high-strength steel was treated with standard hard chromium and self-developed micro-crack chromium techniques respectively. The effects of two chromium plating technique on fatigue properties of 30CrMnSiA high-strength steel were evaluated by rotary bending fatigue test. Meanwhile, the effect of copper plating pretreatment was compared, and the fracture morphology was analyzed by FESEM. The results showed that compared with the hard chromium coating, the surface micro-cracks of self-developed micro-crack chromium plating were shallow and fine, and had more numbers, with the density of micro-cracks was up to 1020 lines/cm, and the cracks did not penetrate the plating and were distributed in layers. Under the stress of 850 MPa, hard chromium plating of 30 μm would reduce the median fatigue life of 30CrMnSiA high-strength steel by about 48%, and the fatigue fracture is characterized by multi-sources. However, the self-developed micro-crack chromium plating with the same thickness only reduced the fatigue life of the substrate by 23%. After the fatigue test, no obvious cracks were found on the micro-cracked Cr-plating, and the cracks propagated in multi-direction. The fatigue resistance of 30CrMnSiA treated by self-developed micro-crack chromium technique was significantly better than that of hard chromium plating. In addition, if the copper-plated transition layer was introduced between the substrate/chromium plating, the number of cracks reaching the substrate could be effectively reduced, the fatigue performance of 30CrMnSiA high-strength steel was obviously improved, and the median fatigue life was almost close to the matrix.