ABSTRACT

Hard turning process, frequently used to finish the rotational surfaces of hard steel components, has some major issues like a high tool wear rate coupled with the degradation of surface finish and generation of brittle white layer. Due to this, the process productivity also remains low. In an attempt to improve the cutting tool productivity while machining hardened EN31 steel, uncoated ceramic inserts were used with the Minimum Quantity Lubrication (MQL) environment, which resulted in significant wear reduction on the ceramic inserts along with a better surface finish than that produced with a dry cutting. The most suitable process parameters, to produce an efficient cut, i.e., high process performance on both wear and surface finish fronts, were proposed. The surface integrity produced within the process parameter window identified was compared for both dry and MQL environments. It was confirmed that application of MQL brought about a significant reduction in formation of subsurface white layer both at lower and higher feeds (around 40% and 16.5% respectively) when compared to dry mode cutting. MQL condition enhanced the overall productivity of ceramic inserts with lower flank wear and better surface characteristics even at higher feeds, while at the same time, producing a thinner white layer.

摘要

经常用于精加工硬钢部件的旋转表面的硬车削工艺存在一些主要问题，例如刀具磨损率高、表面光洁度下降和产生脆性白层。因此，工艺生产率也仍然很低。为了在加工硬化 EN31 钢时提高切削刀具的生产率，在最小量润滑 (MQL) 环境中使用无涂层陶瓷刀片，这导致陶瓷刀片的磨损显着减少，并且表面光洁度比使用干切。提出了最合适的工艺参数，以产生有效的切削，即磨损和表面光洁度方面的高工艺性能。在确定的工艺参数窗口内产生的表面完整性在干燥和 MQL 环境中进行了比较。已证实，与干式切削相比，MQL 的应用在较低和较高进给量（分别约为 40% 和 16.5%）下均显着减少了表层下白色层的形成。MQL 条件提高了陶瓷刀片的整体生产率，即使在较高进给量下也具有较低的后刀面磨损和更好的表面特性，同时产生更薄的白色层。