采用低碳Mn-Mo-Nb-Cr-Ni系的成分设计，并通过炉卷轧机高密层流冷却装置直接淬火工艺，配以合适的回火制度，生产了屈服强度高于800MPa，-40℃冲击功达到100J以上的高强工程机械用Q800D/E钢板。回火温度升高过程中，Q800D/E钢板中的析出物呈现先长大而后重新形核析出随后再粗化的过程，是其强度随回火温度升高呈现先下降后上升而后再下降的原因所在。

Using high density laminar cooling device of steckel mill, low carbon Mn-Mo-Nb-Cr-Ni series Q800D/E grade construction machinery steel was produced by direct quenching and off-line tempering technique. The yield strength of the plate was more than 800MPa and the CVN impact energy at - 40℃ was more than 100J after appropriate tempering. During tempering temperature rising, the precipitates in Q800D/E exhibited growing, re-nucleating and coarsing process, which would lead to the fluctuation of the plate strength.