Abstract

Ultrahigh level of strength, toughness, good weldability, and also weight reduction are the key issues in the automotive and structural industries for improving fuel efficiency and the economy of structure fabrication. The present investigation has produced an ultrahigh strength low carbon Cu bearing steel through the thermo-mechanically controlled processing (TMCP). Here Cu not only acts as a precipitation former but also delays the recrystallisation through a solute drag effect. The steel shows Cu-rich precipitates within the bainite-martensite microstructure. Cu-rich particles within the lower bainite, precipitation strengthening, solid solution strengthening, and delayed recrystallisation significantly improve the yield strength (≈1.25 GPa) and the strain hardening ability. The present steel has shown an excellent combination of mechanical properties comprising of ultra-high ultimate tensile strength >1550 MPa with ductility >12% and satisfactory low-temperature toughness (28 J/cm²). The investigated steel with low carbon content is expected to have good weldability.

中文翻译：

---

TMCP参数对低碳含铜超高强度钢组织和性能的影响

摘要

超高水平的强度，韧性，良好的可焊接性以及减轻重量是汽车和结构工业中提高燃油效率和结构制造经济性的关键问题。本研究通过热机械控制工艺（TMCP）生产了超高强度低碳Cu轴承钢。在这里，Cu不仅起沉淀剂的作用，而且还通过溶质拖曳作用延迟了再结晶。该钢在贝氏体-马氏体的显微组织中显示出富铜的沉淀物。下贝氏体中的富铜颗粒，沉淀强化，固溶强化和延迟的再结晶显着提高了屈服强度（≈1.25GPa）和应变硬化能力。²）。被调查的低碳钢有望具有良好的焊接性。