淬火过程流动及热参数的研究进展

Research progress of flow and thermal parameters during quenching process

流动和热参量是淬火过程中控制淬火质量的关键点。利用热电偶或非接触式温度测量仪可以得到淬火工件表面的温度,并以此对传热过程进行研究,以评定淬火介质的热交换和冷却能力。通过一定技术手段对介质流场结构尤其是流速进行测定,以保证淬火质量、提高淬火效率。淬火过程中发生的汽液两相流动沸腾现象使得淬火过程更加复杂。膜态沸腾阶段和核态沸腾阶段是沸腾现象的重要研究内容,而其中涉及的蒸汽膜物理特性试验研究,以及通过纳米改性技术主动或被动改变试件材料表面微观性质以此改变临界热流密度的试验研究成为当前沸腾现象试验研究的新动向。

Flow and thermal parameters are key points throughout the quenching process to control the heat treatment effect of workpieces.The surface temperature of workpieces,which can be measured by thermocouples or non-contact thermal measuring instrument,was analyzed to investigate the cooling capacity of the quenchant and heat exchange rate between the quenchant and workpiece. The flow field structure of the quenchant,indicated by the flow velocity vectors,was measured to ensure the quenching quality and improve the quenching efficiency.Furthermore,more details have been unveiled through the studies of the vapor-liquid two-phase flow and boiling phenomenon during the quenching process,and the film boiling and nucleate boiling stages are becoming the cutting edge field. Nowadays,actively or passively modifying the surficial micro-properties of workpieces by nano-modification technology has become the research hot point.