以Q450NQR1和S500AW两种车体钢为研究对象，通过选用四点弯曲、U型弯曲、慢应变速率拉伸的应力加载方式和电化学测试相结合，研究了这两种车体钢的应力腐蚀开裂敏感性。结果表明：经50%屈服强度应力加载后，两种四点弯曲试样的开路电位最高，提高载荷，电位逐渐负移；经U型弯曲试验后，两种试样弯曲处均未发现裂纹，且随着腐蚀时间的延长，其开路电位负移并逐渐趋于稳定；经慢应变速率试验后，S500AW试样的屈服后塑性变形区域及弹性变形区域高于Q450NQR1试样的，其力学性能更好。

Taking Q450NQR1 and S500AW car body steels as research objects, the stress corrosion cracking susceptibility of two car body steels was studied through four-point bending, U-shaped bending, slow strain rate tensile loading methods combined with electrochemical tests. The results showed that the open circuit potential of the two four-point bending specimens was the highest after being loaded with 50% yield strength stress.When the load increased, the potential gradually shifted negatively. After U-shaped bending test, no cracks were found in the bend of the two samples, and with the extension of the corrosion time, the open circuit potential shifted negatively and gradually stabilized. After the slow strain rate test, the post-yield plastic deformation area and elastic deformation area of the S500AW specimen were higher than those of the Q450NQR1 specimen, and its mechanical properties were relatively good.