Abstract

The continuous direct extrusion is an economic and efficient process to manufacture high-quality aluminium profiles. However, because of multiple billets processing, transient defects (coring and charge welds) can be generated affecting portions of the profiles and deteriorating their mechanical properties. In case of structural applications, the reliable prediction of the onset and extend of these portions is therefore mandatory in order to be scrapped by the commercialized length. In this context, the present work has been aimed at examining the dynamic evolution of the coring and charge weld defects in the direct extrusion of an industrial solid profile. Both experimental and numerical activities have been performed and results evaluated in terms of coring and charge welds defect evolution achieving a good agreement for both phenomena. Results have been also compared with the outcomes of the analytical models available in literature. For the charge weld extension, the analytical model returned a poor predictably while a very good match with numerical data was obtained for the coring defect.

中文翻译：

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直接挤出中的废料评估

摘要

连续直接挤压是制造高质量铝型材的经济有效的方法。但是，由于进行了多个坯料加工，可能会产生瞬态缺陷（取芯和装料焊缝），从而影响型材的某些部分并降低其机械性能。因此，在结构应用的情况下，必须可靠地预测这些部分的开始和延伸，以免被商业化长度所废弃。在这种情况下，目前的工作旨在检查在直接挤压工业固体型材时取芯和补焊缺陷的动态演变。已经进行了实验和数值活动，并根据取芯和电荷焊缝缺陷演变评估了结果，从而对两种现象都达成了良好的共识。还将结果与文献中可用的分析模型的结果进行了比较。对于充电焊缝扩展，分析模型可预测地返回差的结果，而与取芯缺陷的数值数据非常吻合。