浅析用铬刚玉砂轮代替白刚玉、棕刚玉砂轮

介绍铬刚玉砂轮、白刚玉砂轮、棕刚玉砂轮的特点以及用铬刚玉砂轮代替白刚玉砂轮、棕刚玉砂轮的实用价值。     

青刚玉树脂砂轮

过去,国内机加工行业切钢材一般采用棕刚玉或白刚玉砂轮,在切割各种不锈钢材等难加工的材料时,这些砂轮的耐用度和切削效率都比较低。最近,首都机械厂采用自己研制成的青刚玉树脂砂轮,切割速度快,耐用,噪声小,适于切割各种管材、型材和不锈钢等难加工的材料。与普通砂轮相     

镨钕刚玉

为了提高磨削效率,解决难磨材料的磨加工问题,我所新刚玉研制组利用我国丰富的稀土资源,研制成功一种新型磨料-错钕刚玉(代号为GP)。镨钕刚玉是在白刚玉中,加入镨钕氧化物制成的,其生产工艺简单而无毒,这是它在制造工艺上比单晶刚玉优越的地方。采用通常的陶瓷、树脂和橡胶结合剂即可制成各种规格形状的磨具。镨钕刚玉砂轮的使用和修整方法与一般砂轮相同。它本身的显微硬度较高,平均为2478公斤/毫米~2(单晶刚     

采用刚玉质造型材料提高大中型铸钢件质量

我厂铸钢车间年产铸件4000 t,单件最大浇注重量为30 t,铸件最大壁厚达400mm。其中,一部分厚大铸件远销美国,其表面质量要求较高,为此,我们采用刚玉质造型材料来提高这些铸件的表面质量。刚玉质造型材料包括:棕刚玉型砂、铝矾土一棕刚玉粉复合涂料、刚玉质商品涂料。长期的生产实践证明,刚玉质造型材料具有优良的防粘砂性能,是一种用量少、效果好并能提高铸件表面质量的优质特种造型材料。现将我厂使用刚玉质造型材料的情况介绍如下。一.刚玉质原材料我们使用的刚玉质原材料主要有棕刚玉砂、棕刚玉粉和铝矾土粉。1.棕刚玉砂和棕刚玉粉棕刚玉砂(粉)的主要化学成分为Al_2O_3。它是以铝矾土为主要原料,在电弧炉内经高温(2000℃以上)熔炼后冷却得到的棕刚玉块,再通过破碎、     

青刚玉树脂切割砂轮通过技术鉴定

由航天工业部首都机械厂新工艺试验室研制成功的青刚玉树脂切割砂轮,一九八三年十月七日在北京由航天工业部组织四十一个单位,七十二名专家、教授和代表参加通过了技术鉴定。青刚玉树脂切割砂轮具有强度高、韧性好、切削锋利、抗磨屑的粘附能力强等特点。经近十个单位使用证明,该砂轮与目前使用的棕刚玉和白刚玉树脂砂轮相比,用于切断普通钢材中的管材、角材、型材效果较好;用于切断不锈钢和其他难加工的合金钢效果显著。如磨削比提高30％以上,切削效率可提高一倍左右。     

刚玉砂轮外圆磨削微观热流体动压效应分析

为了研究陶瓷刚玉砂轮外圆磨削轴承钢(GCr15)时的流体动压效应,基于弹性流体动力润滑理论,建立稳态微观热弹流砂轮模型;对比分析等温条件下陶瓷刚玉磨料、金刚石磨料、CBN磨料的流体动压效应,分析热效应以及粗糙度幅值和波长对乳化液润滑时流体动压效应的影响。结果表明:陶瓷刚玉磨料砂轮相比于其他磨料砂轮的整体压力最小,整体膜厚最大;磨削过程中热效应的影响不可忽略,考虑热效应的影响时,磨削区压力和膜厚减小;随着粗糙度幅值的增大,压力增大,膜厚减小;粗糙度的波长主要和粗糙峰的疏密程度有关,对流体动压力和膜厚的影响较小。     

磨床砂轮修整工艺

<正>1砂轮修整工艺选择因素(1)砂轮加工形面砂轮形面按形状可分为两类:单一形面,如切槽、磨外圆砂轮形面;复杂形面,如磨阶梯外圆、同时磨削端面、外圆复合磨砂轮形面等。(2)修整工具种类修整工具主要分为五类:金刚笔、金刚刀、单颗金刚石、金刚石片状修整器和金刚滚轮。金刚笔、金刚刀主要用来修整刚玉系列砂轮,可修整砂轮的端面、外圆,能修整出复合曲面;滚轮除可修整刚玉系列砂     

电镀CBN锥砂轮磨齿热状态的研究

通过对磨齿过程中砂轮与工件系统的分析 ,建立了锥砂轮磨齿热状态分析模型 ,并分别运用一维传热杆模型及有限单元法分析、计算了磨削所引起的齿面表层的温度场 ;同时 ,用电镀CBN、陶瓷CBN和刚玉砂轮做模拟磨齿试验 ,考察了不同的砂轮及工艺参数对齿面温度的影响。结果表明 ,试验结果与计算结果基本吻合 ,电镀CBN锥砂轮磨削所引起的齿面温升仅是刚玉砂轮的 5 0 % ,比陶瓷CBN砂轮亦低。     

磨削参数对GH4169高温合金磨削表面特征影响研究

采用单因素试验法,使用不同特性的砂轮进行GH4169高温合金的外圆磨削试验,研究了单晶刚玉砂轮和CBN砂轮对GH4169高温合金磨削表面特征中表面粗糙度和表面形貌的影响,分析了各磨削工艺参数对表面粗糙度的影响规律,并分析了单晶刚玉砂轮和CBN砂轮切屑的形态,还检测了磨削加工的表面形貌。结果表明：采用粒度为80、中软级、陶瓷结合剂的单晶刚玉砂轮磨削GH4169高温合金时,其磨削表面粗糙度较小,表面特征较稳定;磨削进给运动轨迹构成了试件已加工表面形貌轮廓的主要特征。在工件速度为8~21.66m/min、砂轮速度为15~30m/s、径向进给量为0.005~0.02mm、纵向进给量为1.3~3.6mm/r范围内,可以保证表面粗糙度Ra在0.14μm以内。     

国内博士、硕士论文摘要

论文摘要报道格式 论文序号(博士论文用B,硕士论文用S),“论文题目(中、英文题目)”,博士或硕士姓名,授学位日期,指导老师单位及姓名,摘要内容(200字左右)。 S 18关于钢坯修庭中磨削比的一些试验研究 A study On thegrindingratioinsteelcondition-ing.金训胜硕士,1986,6,18.东北工学院郑焕之教授。本文以国产棕刚玉及锆刚玉砂轮为对象,经磨削试验,分析了其修磨指标的不同变化规律,观察了磨粒磨损的微观机制,并由此对荒磨砂轮磨耗、破碎、脱落的性质及其间的关系进行了分析;探讨了磨削比低的原因和提高磨制比的途径,为砂轮厂研制高质量荒…     

Assessment of white layer in hardened AISI 52100 steel and its prediction using grinding power

In the present work, the effect of various grinding mechanisms on white layer (WL) formation in AISI 52100 steel is studied using two types of alumina grains, one produced by sol–gel process and the other by conventional fusion. Further, a novel approach is proposed on predicting the WL formation using grinding power. This study correlates the power variation with the change in the metallurgical aspects of the work material. WL of about 56 µm thickness is observed in the material ground by worn out sol–gel alumina wheel. However, no WL is present in the material ground by fused alumina wheel. High toughness in sol–gel alumina led to generation of wear flats with increasing grinding passes and transformed the dominant grinding mechanism from shearing to plowing and sliding. This increases the temperature in the grinding zone, which was the reason for WL formation. Change in the dominant grinding mechanisms from shearing is found to increase the grinding power. Since the change in dominant grinding mechanisms is the cause for WL formation, the increase in grinding power is found to be a good measure in predicting the WL formation. The predictability of WL formation by grinding power is further validated by comparing the power variation in grinding process by both the grinding wheels.     

SG砂轮磨削航空合金温度研究

钛合金和高温合金的导热性差,磨削过程中产生的高温不仅加速砂轮的磨损,而且降低工件表面质量,磨削温度是影响磨削过程的重要参数。本文重点阐述了夹丝半人工热电偶法测温原理及标定方法,并对不同磨削条件下磨削航空合金的温度进行了实验研究。实验选用新型陶瓷氧化铝SG砂轮和普通GC砂轮,分析磨削温度信号的物理意义,系统地研究了磨削用量、磨削方式、砂轮类型以及工件材料对航空合金磨削时温度的影响,为航空合金的高效高精度磨削加工工艺优化提供实验依据。     

Grinding with directionally aligned SiC whisker wheel-loading-free grinding

A new grinding wheel has been developed, wherein very fine SiC whiskers are aligned normally to the grinding surface. However, the grinding wheel exhibits a tendency toward loading. In this study, a method to improve grinding efficiency was proposed. The loading of the grinding wheel could be remarkably reduced by the addition of a small amount of very fine abrasive grains to the grinding fluid. The experimental results showed that alumina of 0.6-μm grain size is most suitable, and a concentration of 0.25% wt is sufficient to prevent the loading. The grinding efficiency and grinding ratio were remarkably improved by this method.     

Experimental investigation and numerical analysis for machinability of alumina ceramic by laser-assisted grinding

Alumina (Al₂O₃) ceramic has been widely used in various fields, but it has certain difficulties in machining as a hard and brittle material. While laser-assisted grinding (LAG), an alternative and novel method for fabrication of alumina ceramic, can utilize laser beam to locally heat the workpiece before the ceramic is removed, thereby reducing fracture toughness and keeping the surface integrity. In this paper, a thermal model is established to study and understand the processing mechanism of the LAG process. Meanwhile, an orthogonal experiment is designed and implemented to optimize the grinding process. Then, by analyzing the surface topography, the advantages of LAG are strongly proved. It is found that the temperature modelling results matches experimental results well. The processing parameter that has greatest impact on surface roughness is laser power, followed by grinding depth and wheel speed, and feeding speed at last. The optimal surface roughness value can be obtained by certain processing parameters. Also, compared to conventional grinding (CG), the removal method of alumina ceramics alters from brittle fracture to plastic fracture. Overall, this study clearly elucidates that LAG of alumina ceramic is a very promising machining method, and can be potentially utilized for various industrial, aerospace and automobile applications.     

Effects of Abrasive Types on Grinding of Chopped Strand Mat Glass Fiber-Reinforced Polymer Composite Laminates

A grindability study of chopped strand mat glass fiber reinforced polymer laminates (CSM GFRP) has been carried out to evaluate the effects of abrasive types on grinding force ratio and area roughness at varying grinding parameters such as speed, feed and depth of cut. Performances of alumina (Al₂O₃) and cubic boron nitride (CBN) wheels were compared. Both wheels delivered the maximum grinding force ratios at low speed, high feed and low depth of cut. Alumina wheel produced smoother surface when grinding at low speed, low feed and high depth of cut. CBN wheel, on the other hand, gave smoother surface at high feed and low depth of cut conditions, regardless of speed. With CBN wheel, it is likely that a single grinding condition exists that maximizes grinding force ratio and minimizes area roughness. The findings indicate that CBN wheel exhibited higher grinding force ratio than alumina grinding wheel in general. CBN grinding wheel also outperformed alumina grinding wheel by producing smoother ground surface in most cases.     

氧化铝空心球砂带磨削钛合金的材料去除及表面质量研究

为了解决航空发动机钛合金叶片磨削加工中砂带使用寿命不足的问题,采用新型氧化铝空心球开展钛合金试样砂带磨削的相关工艺试验研究。通过单因素试验分析氧化铝空心球砂带加工钛合金板材中工艺参数对表面粗糙度和磨削比的影响,确定空心球砂带磨削钛合金参数的合理范围,进而通过正交试验研究磨削压力、磨削线速度、进给速度以及磨粒粒度等因素对表面粗糙度和磨削比的影响程度,确定空心球砂带磨削钛合金的最优工艺参数组合。     

Cu-3镍铜合金砂带磨削试验研究

分析了Cu-3镍铜合金砂带磨削加工过程中,砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量和砂带磨损的影响。采用氧化铝磨料砂带在不同的砂带线速度或磨削压力下对镍铜合金进行了工艺试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量。研究表明:增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比;随着磨削压力的增大,工件表面粗糙度呈增大趋势;随着砂带粒度的增大,工件表面粗糙度呈减小趋势;砂带线速度为25m/s,磨削压力为43N,砂带粒度为P240时,镍铜合金综合磨削效果最好。     

氧化铝砂轮地貌的量化评价及数学建模

砂轮地貌特征是指砂轮表面磨粒密度、磨粒切削刃和磨粒出刃高度分布等情况。准确测量和量化评价砂轮地貌不仅有助于加深对磨削机理的认识,而且是磨削过程优化、磨削过程建模与仿真不可缺少的前提条件。采用白光干涉仪对氧化铝砂轮地貌进行了测量;用伯明翰三维表面粗糙度特征参数量化砂轮地貌特征,评价不同粒度号氧化铝砂轮的磨粒密度、磨粒形状和磨粒锋利程度;根据磨粒出刃高度测量结果,利用统计方法建立氧化铝砂轮表面磨粒出刃高度分布的数学模型。结果表明,氧化铝砂轮表面磨刃形状近似为尖端带有圆球半径的圆锥形状,随着砂轮粒度号数的增加,磨刃的圆头半径减小;在同一砂轮修整工艺条件下,磨刃的顶锥角相差不大;氧化铝砂轮表面磨粒出刃高度符合正态分布规律。     

磨削加工技术的发展及现状

介绍了磨削加工技术的起源及其在国内外的发展现状,提出了目前高速和超高速磨削是提高磨削效率、提高工件表面粗糙度和零件加工品质的先进加工技术;分析了磨削加工技术的机理、优越性和影响因素;阐述了磨削加工技术的发展前景.     

Application of self-inhaling internal cooling wheel in vertical surface grinding

There is less research on vertical sculptured grinding technology. Especially in high vertical surface grinding process with the cup abrasive wheel, the thermal damage is prone to happen and undermine the grinding surface integrity. This problem limits to improve the grinding efficiency and the grinding ratio greatly. Through the analysis of vertical surface grinding process and features in depth, this paper revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel. Based on the previous research achievements, the grinding experiments on TC4 （Ti-6A1-4V） and GH4169 are carried out utilizing the self-inhaling internal cooling wheel. The experimental results show that the self-inhaling internal cooling wheel can efficiently reduce the grinding surface temperature. Moreover, the inherent mechanism of reducing the grinding temperature using the internal cooling method is revealed. Meanwhile, under the same grinding conditions, the grinding ratio during the experiments on GH4169 using self-inhaling internal cooling method is about 3 times as high as using conventional external cooling method. And the grinding forces can be reduced by about 20%. This research revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel, which provides theoretical basis for the design and application of self-inhaling internal cooling wheel. At the same time, an efficient and non-invasive surface grinding method of TC4 and GH4169 is presented.