The accelerated formation of bainite in presence of martensite is opening a new processing window for the steel industry. However, for a feasible industrial implementation, it is necessary to determine the mechanical behaviour of the steels developed under such conditions. This study focuses on analysing the effects of the formation of athermal martensite, followed by the formation of bainitic ferrite, on the mechanical response of a low-C high-Si steel. For this purpose, microhardness measurements and tensile tests have been performed on specimens that were thermally treated either above or below the martensite-start temperature (M_s). Specimens isothermally treated below M_s exhibit a good combination of mechanical properties, comparable with that of the specimens heat treated by conventional treatments above M_s, where there was no prior formation of martensite. Investigations show an increase of the yield stress and a decrease of the ultimate tensile strength as the isothermal holding temperature is decreased below M_s. The formation of prior athermal martensite and its tempering during the isothermal holding leads to the strengthening of the specimens isothermally heat treated below M_s at the expense of slightly decreasing their strain hardening capacity.

在马氏体存在下贝氏体的加速形成为钢铁工业打开了新的加工窗口。然而，为了可行的工业实施，必须确定在这种条件下开发的钢的机械性能。这项研究的重点是分析无热马氏体的形成以及贝氏体铁素体的形成对低碳高硅钢力学响应的影响。为了这个目的，已经对在高于或低于马氏体起始温度（M _s）进行热处理的样品上进行了显微硬度测量和拉伸试验。样品在M _s以下进行等温处理表现出良好的机械性能组合，与在M _s以上通过常规处理热处理过的样品（在此之前未形成马氏体）相当。研究表明，当等温保温温度降低到M _s以下时，屈服应力增加，极限抗拉强度降低。在等温保温过程中，先生的无热马氏体的形成及其回火导致在M _s以下进行等温热处理的试样的强化，其代价是稍微降低了其应变硬化能力。