The effect of adding MgO nanoparticles to ship plate steel at welding heat-affected zones (HAZs) was experimentally studied. The results showed that the added nanoparticles obviously optimised the inclusions; the average size of the inclusions was significantly reduced, and the distribution was relatively uniform. The toughness of the base metal and HAZ increased by 20–60 J, apart from a slight decrease in the strength of the fine-grained heat-affected zone and a nearly unchanged strength in the coarse-grained heat-affected zone, and approximately ∼2 μm (Mg–Al–Ti)O-containing inclusions induced acicular ferrite effectively, thereby simultaneously enhancing the strength and toughness of the inter-critical heat-affected zone. In conclusion, these performance improvements in both the base metal and HAZ could be attributed to grain refinement and inclusion optimisation.

中文翻译：

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MgO纳米颗粒优化夹杂物增韧船板钢热影响区

实验研究了在焊接热影响区 (HAZ) 处向船板钢中添加 MgO 纳米颗粒的效果。结果表明，添加的纳米颗粒对夹杂物进行了明显优化；夹杂物平均尺寸明显减小，分布较为均匀。除了细晶热影响区的强度略有下降和粗晶热影响区的强度几乎没有变化外，母材和热影响区的韧性增加了 20-60 J，大约2 μm (Mg-Al-Ti)O 夹杂物有效诱导针状铁素体，从而同时提高了临界间热影响区的强度和韧性。综上所述，