Development of TRIP-aided Steels for Diesel Engine Common Rail Enduring Ultra High Pressure

针对柴油机共轨系统承受3000 bar超高压的要求，研制了0.2-0.4%C-1.5%Si-1.5%Mn-0. 05% Nb-Cr-Mo-Ni-B系TRIP强化贝氏体铁素体钢（TBF钢）和TRIP强化马氏体钢（TM钢）。此外，为了实现高强度和韧性的组合以及高缺口疲劳强度，提出了以下内容。(1)TBF和TM钢的最佳化学成分。(2)（3）贝氏体铁素体与马氏体的最佳BF/M比及富碳机理

For application to diesel engine common rail enduring ultra high-pressure of 3000 bar, 0.2-0.4%C-1.5%Si-1.5%Mn-0.05%Nb-Cr-Mo-Ni-B TRIP-aided bainitic ferrite steels (TBF steels) and TRIP-aided martensitic steels (TM steels) were developed. In addition, the followings were proposed to achieve high combination of strength and toughness and high notch-fatigue strength.(1) optimum chemical composition for the TBF and TM steels.(2) ultra-fine graining by hot-forging and consequent austempering or isothermal transformationholding(3) optimum ratio (BF/M) of bainitic ferrite and martensite and carbon-enrichment mechanism