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本文论述了含硼低合金结构钢(25MD4和MCD4)冷却时M_(28)(B,C)_沉淀以及奥氏体化时该相重溶的主要特性。介绍和讨论了这两种钢的淬透性和奥氏体转变条件的详尽研究结果。这些结果表明,(可固溶)硼的最佳含量为10～30ppm。还分别确定了不可重固溶的硼碳化物和晶间沉淀物的作用。马氏体淬火和回火(550°或650℃)状态钢的冲击强度取决于硼含量。指明了晶间沉淀物M_(28)(B,C)_数量和冲击韧性之间的关系。这些结果更好地说明了硼的作用,从而推荐采用含这种元素的低合金钢。
In this paper, the main properties of M_ (28) (B, C) _ precipitation during the cooling of boron-containing low-alloy structural steels (25MD4 and MCD4) and the phase remelting during austenitizing are discussed. An exhaustive study of the hardenability and austenite transformation conditions of both steels is presented and discussed. These results indicate that the optimum content of (soluble) boron is 10 to 30 ppm. The roles of non-re-soluable boron carbides and intergranular precipitates were also determined respectively. Martensitic quenching and tempering (550 ° or 650 ° C) Steel impact strength depends on the boron content. The relationship between the amount of M_ (28) (B, C) _ intergranular precipitates and the impact toughness is indicated. These results provide a better illustration of the role of boron, recommending the use of low-alloy steels containing this element.