基于开放孔隙的钎焊CBN多孔砂轮研制与磨削加工性能

Grinding performance of brazed CBN porous abrasive wheels based on open pore structures

为解决钛合金磨削过程中存在的加工效率低、工具寿命短、加工表面质量差等问题,采用冷压成型和高温钎焊技术研制集孔隙率高、耐磨性好和自锐性能优异等特点于一体,基于开放孔隙的钎焊CBN多孔超硬磨料砂轮。完成该砂轮的开放孔隙结构设计与制备,开展钛合金磨削加工性能和磨损试验研究,分析磨削用量参数对钛合金加工性能的影响规律,揭示其自锐性能以及其对工件表面质量的影响。结果表明:当CBN砂轮孔隙尺寸和孔隙率分别为0.6~0.8 mm和40%时,砂轮工作层节块能获得较优的力学性能和较大的容屑空间;与磨削速度30 m/s相比,当磨削速度为80 m/s时,多孔CBN砂轮拥有更为稳定的磨削力比,处于1.5~2.2;随着累计材料去除体积的增大,砂轮表面动态有效磨刃数趋于一致,加工表面粗糙度快速降低并逐渐稳定。

In order to solve the problems,such as the low machining efficiency,short service life of abrasive tools,and poor ground surface quality,brazed cubic boron nitride(CBN)porous abrasive wheels coupled with high porosity,good wear resistance and excellent self-sharpening ability were fabricated.Open pore structures were designed,and then the grinding performance and wear experiments were conducted in grinding of Ti-6Al-4V titanium alloys.Grindability and ground surface quality of Ti-6Al-4V alloys affected by grinding parameters were discussed in detail.In addition,the self-sharpening ability of brazed CBN porous abrasive wheels was analyzed.Results shows that brazed CBN porous abrasive wheels featured a desired flexural strength and excellent chip storage space after optimizing the pore size of 0.6~0.8 mm and designed porosity of 40%.The brazed CBN porous abrasive wheels showed a more stable grinding force ratio from 1.5 to 2.2 with the grinding speed of 80 m/s compared to that with the grinding speed of 30 m/s.Moreover,with the increase of material removal volume,the ground surface roughness rapidly declined and stabilized due to the stabilization of the dynamic effective grains number.