Comparative study on machining behavior of brazed CBN wheel and vitrified CBN wheel during grinding powder metallurgy superalloy
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摘要: 采用钎焊CBN砂轮和陶瓷CBN砂轮进行FGH96粉末冶金高温合金磨削对比试验,从磨削力与温度、表面粗糙度以及砂轮磨损等方面对CBN砂轮磨削性能进行评价。结果表明:钎焊CBN砂轮磨削力接近或低于陶瓷CBN砂轮的; 在较低进给速度下(≤360 mm/min),钎焊CBN砂轮磨削温度与陶瓷CBN砂轮的相近,在较高进给速度下(≥540 mm/min),陶瓷CBN砂轮的磨削温度明显高于钎焊CBN砂轮的; 在正常磨削条件下,钎焊CBN砂轮磨削后工件的表面粗糙度低于陶瓷CBN砂轮的,且表面粗糙度Ra均在0.800 μm以下,平均表面粗糙度Ra分别为0.508 μm和0.529 μm。钎焊CBN砂轮工作面磨粒发生材料黏附、磨耗磨损,磨削表面出现材料涂覆等现象;除磨耗磨损、黏附和砂轮堵塞外,由于磨粒破碎和脱落,陶瓷CBN砂轮易在其磨削表面形成深沟槽,降低磨削表面质量。综合分析发现,钎焊CBN砂轮磨削FGH96的性能要优于陶瓷CBN砂轮的。Abstract: The comparative grinding test of FGH96 powder metallurgy superalloy was carried out with brazed CBN wheel and ceramic CBN wheel. The grinding performance of CBN wheel was evaluated from the dimensions of grinding force and temperature, surface roughness and wheel wear.The results showed that the grinding force of brazed CBN wheel was close to or lower than that of ceramic CBN wheel, the grinding temperature of brazed CBN wheel was similar to that of ceramic CBN wheel at lower feed speed (≤360 mm/min), and the grinding temperature of ceramic CBN wheel was significantly higher than that of brazed CBN wheel at higher feed speed (≥ 540 mm/min). Under normal grinding conditions, the surface roughness of brazed CBN grinding wheel was lower than that of ceramic CBN grinding wheel, and the surface roughness Ra was lower than 0.800 μm, the average surface roughness Ra was 0.508 μm and 0.529 μm. Material adhesion and abrasion wear occurred in the abrasive grains on the working face of brazed CBN abrasive wheel, and the grinding surface appears material smeared. While for that of vitrified CBN abrasive wheel, in addition to wear, adhesion and grinding wheel blockage, the grinding surface was easy to form deep grooves due to grain breakage and falling off, which reduced the machined surface quality. Generally, the grinding performance of brazed CBN abrasive wheel on FGH96 was better than that of vitrified CBN abrasive wheel.
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