磨粒有序多孔立方氮化硼砂轮高效磨削高温合金烧伤研究

Grinding burn in high-efficiency grinding superalloy using porous CBN wheel with multilayer defined grain pattern

针对高温合金高效磨削过程中存在磨削烧伤问题,基于氧化铝空心球造孔与高温钎焊技术,研制了多层磨粒有序排布的多孔立方氮化硼(Cubic Boron Nitride,简称CBN)砂轮,开展了高效磨削GH4169镍基高温合金试验研究,分析了缓进给磨削中工件表面突发性烧伤特征,并提出采用添加石墨导流块来抑制工件烧伤策略。研究结果表明:添加石墨块导流后,缓进深切磨削砂轮最大材料去除率可提高3倍以上。当切深为0.2mm时,高速磨削时砂轮最大材料去除率可达20mm3/(mm·s)。当材料去除率为2mm3/(mm·s)时,随着磨削速度增大,磨削温度先下降后上升,当vs=80m/s时磨削温度最低。越过临界速度100m/s,磨削温度则呈下降趋势。

Porous CBN wheel with multilayer defined grain pattern was developed based on pore-forming effect of alumina bubbles and brazing technology.High-efficiency grinding experiments were carried out on a typical nickel-based superalloy GH4169,and the grinding burn on the ground surface was studied.A strategy to control the grinding burn by clapping guiding graphite blocks around the workpiece was proposed,which would improve the cooling effect in the grinding zone.The material removal rate was at least 3 times higher by clapping graphite blocks in deep grinding,and up to 20 mm3/（mm？？s） in high speed grinding at the cutting depth of 0.2 mm.In deep grinding with material removal rate 2 mm3/（mm？？s）,as grinding speed increased, the grinding temperature firstly decreased down to the lowest when v s was 80 m/s,then increased to the top,at the critical speed of 100 m/s,and afterwards it decreased again.