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本文以28Cr_2MoV 钢为对象,研究了通过改善显微组织形态提高调质高强度钢强韧性的效果和强韧化机理。实验表明:合理设计新的热处理工艺,可使这种钢从低温到高温整个回火温区的韧性(a_K、K_(1c))普遍提高。分析指出,改善调质态韧性是由于未溶尽的碳化物颗粒在快速奥氏体化淬火中对改善组织形态所起特殊作用的结果。这种颗粒在加热时提供形核位置以细化奥氏体晶粒,在冷却时切变型转变过程中充当位错增殖源,使淬火组织具有高密度位错,这又为回火提供大量形核位置,使碳化物呈细小、均匀分布并大量析出。相应地韧化基体,提高分散强化效果,改善调质钢的韧性。
In this paper, 28Cr_2MoV steel as the object, to study the effect of strengthening the toughness of the quenched and tempered high-strength steel by improving the microstructure and strengthening mechanism. Experiments show that the reasonable design of new heat treatment process can make the toughness (a_K, K_ (1c)) of this steel increase from the low temperature to the high temperature. The analysis indicates that the improvement of temper- ature toughness is the result of the special role of undissolved carbide particles in improving the morphology of the tissue during rapid austenitizing quenching. Such particles provide nucleation sites on heating to refine austenite grains, act as a source of dislocation multiplication during shear-to-shear transformation during cooling, resulting in high density dislocations in the quenched tissue, which in turn provide a large number of shapes for tempering Nuclear position, the carbide was small, evenly distributed and a large number of precipitation. Corresponding to toughen the matrix, improve dispersion strengthening effect, improve the toughness of quenched and tempered steel.