A metallurgical evaluation of tool wear and chip formation when machining pearlitic grey cast irons with dissimilar graphite morphologies
A metallurgical evaluation of tool wear and chip formation when machining pearlitic grey cast irons with dissimilar graphite morphologies
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加工不同石墨形态的珠光体灰铸铁时刀具磨损和切屑形成的冶金评估
DOI：
10.1016/0043-1648(85)90210-8
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发表时间：
1985
期刊：
影响因子：
5
通讯作者：
P. Dearnley
中科院分区：
文献类型：
--
作者：
P. Dearnley
对卓越使用强度的需求意味着越来越多的工程部件现在由含有球状石墨的珠光体铸铁制成，而不是更传统的含有片状石墨的铸铁。工件材料的这种变化导致许多加工操作中刀具寿命的迅速下降，特别是车削和端面加工。本文介绍的工作描述了对切屑形成过程中涉及的因素的研究，这些因素导致观察到的刀具磨损模式。对含有片状（GA 铁）和球状（SG 铁）石墨形态的珠光体灰铸铁、硬质合金（涂层和未涂层）和陶瓷刀具材料进行了一系列车削试验。与球墨铸铁相比，在切削球墨铸铁时，积屑瘤会在更高的切削速度下持续存在，其周期性脱落会导致切削刃磨损或断裂。当高速切削两种铸铁时，涂层刀具和陶瓷刀具的前刀面和后刀面主要发生平滑磨损过程，这可能是由溶解扩散和小应变离散塑性变形引起的。切削 GA 铁时，光滑磨损比 SG 铁慢，因为刀具温度降低，并且从切屑工件沉积的“保护性”非金属层中断了溶解扩散。当切削球墨铸铁时，无涂层硬质合金的快速磨损是由磨损引起的，而当切削球墨铸铁时，相对较慢的光滑磨损是由溶解扩散引起的。
The need for superior in-service strength has meant that an increasing number of engineering components are now being made from pearlitic cast irons containing spheroidal graphite, rather than the more traditional cast irons containing flake graphite. Such changes of workpiece material have resulted in a rapid decline in tool life in many machining operations, particularly turning and facing.An investigation into the factors involved during chip formation which result in the observed patterns of tool wear is described in the work presented here. A series of turning tests were made on pearlitic grey cast irons containing flake (GA iron) and spheroidal (SG iron) graphite morphologies with cemented carbide (coated and uncoated) and ceramic tool materials. Built-up edge persisted to higher cutting speeds when cutting SG iron than GA iron, its periodic detachment causing attrition or fracture of the cutting edge. Smooth wear processes, probably caused by dissolution-diffusion and small strain discrete plastic deformation, were predominant on the rake and flank faces of the coated and ceramic tools when cutting both cast irons at high speed. Smooth wear was less rapid when cutting GA iron than SG iron because tool temperatures were reduced and “protective” nonmetallic layers, deposited from the chip-workpiece, interrupted dissolution-diffusion. When cutting SG iron, rapid wear of the uncoated cemented carbides was caused by attrition, while the relatively slower smooth wear, when cutting GA iron, was caused by dissolution-diffusion.