The influence of the initial structure on formation of austenite, evolution of structure, and elevation of operating characteristics of steel SA508 Gr.3 (0.24% C, 1.40% Mn, 0.88% Ni, 0.54% Mo) after an intercritical heat treatment (IHT) is studied. After the IHT, the grain size of the hypoeutectoid ferrite in the steel with an initially ferritic-bainitic structure is much larger than in the initially bainitic or martensitic structures. The density of the low-angle and high-angle boundaries is much higher in the steel with initial bainitic or martensitic microstructure. The initial microstructure affects substantially the strength and the impact toughness of the steel subjected to IHT. The mechanical properties are increased as a result of refinement of the microstructure and growth of the density of grain boundaries.

SA508 Gr.3钢（0.24% C, 1.40% Mn, 0.88% Ni, 0.54% Mo）经过临界间热处理（IHT）后初始组织对奥氏体形成、组织演变和操作特性提升的影响) 进行了研究。在 IHT 之后，具有初始铁素体-贝氏体组织的钢中亚共析铁素体的晶粒尺寸远大于初始贝氏体或马氏体组织中的晶粒尺寸。在具有初始贝氏体或马氏体组织的钢中，低角度和高角度边界的密度要高得多。初始微观结构显着影响经受 IHT 的钢的强度和冲击韧性。由于微观结构的细化和晶界密度的增长，机械性能得到提高。