Abstract Appropriate graphitisation of a carbon steel may provide an alternative route to developing more simply and inexpensively alloyed machining steels which are more recyclable than those which are currently available. The extent of crystallinity of graphite particles formed during a graphitisation anneal of an experimental carbon steel was studied by Raman spectroscopy. It is demonstrated that it was possible to record the progress of graphitisation with annealing time as well as to determine which starting microstructural conditions, either ferrite-pearlite, bainite or martensite, formed the most highly crystalline graphite particles during annealing. During a machining operation the graphite should act as an internal lubricant at the chip/tool interface and thus the extent of crystallinity may influence the final machinability of the steel, or effectively, optimisation of the heat treatment. It was revealed by the Raman spectra that the crystallinity of the graphite particles formed was strongly affected by the starting microstructures as well as the graphitising anneal periods. For a similar annealing time, a better degree of crystallinity was observed in graphite particles formed from a ferrite-pearlite starting microstructure rather than bainite and martensite starting microstructures. However, crystallinity could be gradually improved with increasing annealing time from all three of the starting microstructures examined.

中文翻译：

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实验性易切削钢中形成的石墨结晶度的拉曼光谱研究

摘要 碳钢的适当石墨化可能为开发更简单、更便宜的合金加工钢提供了一种替代途径，这些钢比目前可用的更可回收利用。通过拉曼光谱研究了在实验碳钢的石墨化退火过程中形成的石墨颗粒的结晶程度。结果表明，可以随退火时间记录石墨化进程，并确定在退火过程中形成最高结晶石墨颗粒的起始微观结构条件，铁素体-珠光体、贝氏体或马氏体。在加工操作期间，石墨应作为切屑/刀具界面处的内部润滑剂，因此结晶度可能会影响钢的最终可加工性，或有效地，优化热处理。拉曼光谱表明，形成的石墨颗粒的结晶度受起始微观结构和石墨化退火周期的强烈影响。对于类似的退火时间，在由铁素体-珠光体起始微观结构而不是贝氏体和马氏体起始微观结构形成的石墨颗粒中观察到更好的结晶度。然而，所有三种初始微观结构的结晶度都可以随着退火时间的增加而逐渐提高。对于类似的退火时间，在由铁素体-珠光体起始微观结构而不是贝氏体和马氏体起始微观结构形成的石墨颗粒中观察到更好的结晶度。然而，所有三种初始微观结构的结晶度都可以随着退火时间的增加而逐渐提高。对于类似的退火时间，在由铁素体-珠光体起始微观结构而不是贝氏体和马氏体起始微观结构形成的石墨颗粒中观察到更好的结晶度。然而，所有三种初始微观结构的结晶度都可以随着退火时间的增加而逐渐提高。