半固态铸造A356铝合金冷却斜槽工艺参数的建模与优化(英文)

使用冷却斜槽工艺加工半固态A356铝合金。运用D-实验优化设计(DODE)设计实验并分析实验结果。采用软件抽取38个随机实验。冷却斜板长度为100、300、500 mm,斜板的斜角为30°、45°、60°,浇铸温度为660、680和700°C。将半固态铝合金浇铸到铜质冷却斜板上,然后倾入到钢模中成型。铸造完成之后,在温度590°C下,对部分样品进行5、8、12 min重熔处理。研究这些因素对初生α(Al)晶体圆整度的影响,并使用DODE进行参数优化处理。结果表明,传统铸造A356合金的初生α(Al)相为枝晶,而冷却斜槽铸造的为非枝晶。重熔后再经过冷却斜槽处理的样品呈现出球状结构。最优的浇铸温度、冷却板长度、斜角和保温时间分别为660°C、360mm、48°和9 min。在最优条件下,得到初生晶体的圆整度为0.91。所建立的模型的相关系数为0.9860。

Evaluation and modification of inclusion characteristics in HK40 heatresistant cast steel

Specifications of inclusions such as the type, morphology, number, composition, size, and place of inclusions in HK40 heat-resistant casting steel were studied by optical microscopy and scanning electron microscopy equipped with an energy-dispersive spectroscopy system. The effects of calcium silicide （CaSi） addition on these characteristics were evaluated at two pouring temperatures of 1420℃ and 1470℃. It was found that most of the appeared inclusions were in the type of chromium oxide. CaSi addition had a significant effect on the morphological modification, size and distribution of inclusions as well as changing the composition to oxide-sulfide compounds.