基于激光离散强化的有序微槽结构电镀砂轮及其磨削窄深槽基础研究

Grinding is an important way to realize finish machining of components with narrow deep groove in the fields of aerospace, national defense and automobile. However, there are several problems during grinding of narrow deep groove, such as poor cooling performance, low bonding strength between electroplated layer and matrix, easy clogging and difficult to dress for grinding wheel. A novel preparation method of grinding wheel is proposed, which is called “electroplating after grooving” for short. According to this method, an electroplated super-abrasive grinding wheel will be developed. The matrix of the electroplated super-abrasive grinding wheel will be discrete quenched by laser beam. High-aspect-ratio ordered microgrooves at only tens of microns in width and hundreds of microns in interval will be equipped on the working surface of the electroplated super-abrasive grinding wheel. The research follows the design theory and preparation method of the electroplated super-abrasive grinding wheel and grinding mechanism of narrow deep groove via this grinding wheel. The key scientific problems, such as influence mechanism of ordered microgroove structure on the grinding quality of narrow deep grooves, bonding mechanism of discrete quenched matrix and electroplated layer, and the interaction mechanism between the working surface of the grinding wheel and narrow deep groove, will be systematically studied. The influence rules of high-aspect-ratio ordered microgroove structure on the cooling performance and chip removal capacity of the grinding wheel and grinding quality will be revealed. The influence mechanism of the strength-toughness alternative structure of the matrix on the bonding strength between the matrix and electroplated layer will be clarified. The machining mechanism of narrow deep groove using the electroplated super-abrasive grinding wheel with ordered microgroove structure will be demonstrated. A theoretical basis and technical support for breaking through the technological bottlenecks during finish machining of narrow deep groove will be provided. This project has both theoretical and practical value for promoting industrial application of the electroplated super-abrasive grinding wheel with ordered microgroove structure and improving the manufacturing capability of the narrow deep grooves.

磨削加工是实现航空航天、国防和汽车等领域窄深槽结构零件精密加工的重要方法，然而窄深槽磨削时存在冷却性能差、砂轮电镀层/基体结合强度低、极易堵塞及修整困难等问题。本项目提出“先槽后砂”砂轮制备方法，研制一种基体激光离散强化、工作面具备宽度仅为数十微米、间距为数百微米的高深宽比有序微槽结构电镀超硬砂轮。以掌握该砂轮设计理论与制备方法及其磨削窄深槽加工机理为主线，系统研究微槽结构对窄深槽磨削质量影响机制、离散强化基体与镀层结合机理、及砂轮服役面与窄深槽相互作用机制等关键科学问题，揭示高深宽比有序微槽结构对砂轮润滑冷却性能、容屑排屑能力和磨削质量的影响规律，阐明强韧相间结构对基体/镀层结合强度的影响机制，明确有序微槽结构电镀砂轮磨削窄深槽加工机理，籍此为突破窄深槽精密加工技术瓶颈提供理论基础和技术支撑。本项目对促进有序微槽结构电镀超硬砂轮的推广应用、提升窄深槽制造水平具有重要理论意义和应用价值。

针对航空航天、国防军工和汽车产业等领域窄深槽结构零件精密磨削时存在冷却性能差、砂轮电镀层/基体结合强度低、极易堵塞及修整困难等问题，本项目提出“先槽后砂”砂轮制备方法，研制了一种基体激光离散强化、工作面具备宽度仅为0.1 mm、间距为0.98 mm、深宽比高达15的有序微槽结构电镀超硬砂轮。以掌握该砂轮设计理论与制备方法及其磨削窄深槽加工机理为主线，系统研究了微槽结构对窄深槽磨削质量影响机制、离散强化基体与镀层结合机理、及砂轮服役面与窄深槽相互作用机制等关键科学问题，揭示了高深宽比有序微槽结构对砂轮润滑冷却性能、容屑排屑能力和磨削质量的影响规律，阐明了强韧相间结构对基体/镀层结合强度的影响机制，明确了有序微槽结构电镀砂轮磨削窄深槽加工机理。研究表明：先制槽再镀砂的电镀砂轮制备方法，能够避免直接在砂轮工作面上结构化处理所引起的超硬磨料损伤问题，提升了电镀砂轮制备品质。离散强化在砂轮基体形成的马氏体抗腐蚀能力强，镀层外延式增长使得镀层/基体结合界面光滑，结合性能显著提升；强化区的高硬度使得镀层硬度提高了18.7%，进而提高了砂轮的磨削承载能力；“强韧相间”结构有效阻止了裂纹的萌生与扩展，极限应变由0.1668降为0.0714，提升了电镀砂轮的抗拉强度和抗热冲击性能，有效防止了磨料过早脱落或镀层剥落。高深宽比微槽结构提高了砂轮的容屑排屑能力，防止砂轮堵塞；磨削液有效流量增大了5.4倍，改善了砂轮和窄深槽工件的润滑冷却性能，磨削力下降了22.5%，磨削温度下降了25.1%，显著降低了磨削损伤。微槽在进入和离开磨削区时产生的振动非常小，磨削表面粗糙度可以与传统砂轮媲美。微槽入口磨料承担的切削力增大，磨粒破碎使得砂轮具有自锐功能，微槽出口磨料磨钝后，由于后面没有电镀层的支撑而脱落，进一步增强了砂轮自锐性能；多层磨料使得电镀砂轮能够修整。本项目为提高有序微槽结构电镀超硬砂轮的制备品质、提升窄深槽零件的制造水平提供了新思路和理论基础。