采用X射线衍射对178mm厚EH690钢不同位置的残余奥氏体及位错密度进行检测。结果表明钢中残余奥氏体的含量可以忽略不计，实验钢的亚表面、t/4和t/2的位错密度分别为2.18 × 10¹⁴ m⁻², 4.17 × 10¹⁴ m⁻²和5.12 × 10¹⁴ m⁻²。

The retained austenite and dislocation density at different positions of 178mm thick EH690 steel were measured by X-ray diffraction. The results show that the content of retained austenite in the steel is negligible, and the dislocation densities of subsurface, t/4 and t/2 are 2.18 × 10¹⁴ m^-2, 4.17 × 10¹⁴ m^-2 and 5.12 × 10¹⁴ m^-2, respectively.