ABSTRACT In the present work the influence of Cerium on the microstructure and the mechanical properties of a cast, quenched and tempered GS33NiCrMo744 steel is analysed. The study shows that the addition of cerium to the steel melt results in an increase of the number of CeS dispersoids with a size between 0.5 and 3.0 µm. The CeS dispersoids change the solidification morphology and the as-cast microstructure because as a nucleating agent for ferrite. Furthermore, a part of the cerium remains dissolved in the steel. The width of the columnar zone in 25 mm thick castings diametrically correlates with the amount of cerium. Furthermore, the secondary dendritic arm spacing (SDAS) has a tendency to decrease. The tensile strength of these cerium treated and then quenched and tempered (Q&T) steels increases with the number of cerium-containing dispersoids. However, samples with a wall thickness of 75 mm do not show this behaviour.

中文翻译：

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铈对铸态钢和 Q&T 钢组织和力学性能的影响

摘要 在目前的工作中，分析了铈对铸造、淬火和回火 GS33NiCrMo744 钢的显微组织和机械性能的影响。研究表明，向钢熔体中添加铈会增加尺寸在 0.5 到 3.0 µm 之间的 CeS 弥散体的数量。由于作为铁素体的成核剂，CeS 弥散体改变了凝固形态和铸态微观结构。此外，一部分铈仍然溶解在钢中。25 mm 厚铸件中柱状区的宽度与铈的量在直径上相关。此外，二次树突臂间距（SDAS）有减小的趋势。这些铈的抗拉强度经过处理然后调质（Q& T) 钢随着含铈分散体的数量增加而增加。然而，壁厚为 75 毫米的样品没有表现出这种行为。