砂带磨削表面粗糙度理论预测及灵敏度分析

目的 以钢化玻璃磨边为研究对象,建立金刚石砂带磨削表面粗糙度理论预测模型,并分析粗糙度对各工艺因素的灵敏度。方法 首先,采用多因素线性回归分析建立了关于磨削工艺参数的粗糙度理论预测模型;其次,通过正交试验研究了磨削压力、砂带线速度和砂带张紧力对粗糙度和材料去除率的影响大小,并得到了工艺参数的优水平组合;再次,根据正交试验结果计算了粗糙度理论预测模型的数学表达式,同时,建立了灵敏度模型来进行工艺因素的灵敏度分析和工艺参数的区间优化;最后,利用随机试验验证了粗糙度理论预测模型的准确性。结果 极差分析可知,RA（0.137）?RC（0.068）?RB（0.016）,MC（6.828）?MA（5.228）?MB（1.784）,磨削工艺参数的优水平组合为A2B3C3。电镀金刚石砂带磨削表面粗糙度理论预测模型的表达式为 。各工艺参数的优选区间为：磨削压力10~20 N,线速度15~30 m/s,张紧力40~60 N。随机试验可得,粗糙度理论预测模型的相对误差大小维持在5.5%~10%。结论 关于工艺因素对磨削质量的影响,磨削压力最大,砂带张紧力次之,砂带线速度最小。关于工艺因素对材料去除率的影响,砂带张紧力最大,磨削压力次之,砂带线速度最小。磨削压力为18 N、砂带线速度为30 m/s、砂带张紧力为55 N时,磨削表面质量最好,且材料去除率较高。试验参数范围内,粗糙度对磨削压力的灵敏度随磨削压力的增加而下降,对砂带线速度和砂带张紧力的灵敏度随着二者的增加而增加。15组随机试验表明,粗糙度理论预测模型具有较高的可靠性和准确性。     

基于改进神经网络算法的螺杆砂带磨削表面粗糙度预测研究

目的 探究工艺参数对螺杆转子砂带磨削表面质量的影响规律。方法 采用工件轴向进给速度为100～300 mm/min、砂带线速度为4.4～13.1 m/s、砂带张紧压力为0.2～0.3 MPa、磨削压力为0.4～0.5 MPa、砂带粒度为120～800目的工艺参数进行螺杆转子砂带磨削正交实验,基于改进的神经网络算法,建立螺杆转子砂带磨削后的表面粗糙度值预测模型,对磨削后的工件表面质量进行预测及分析。在此基础上采用预测模型针对各工艺参数对磨削质量的影响规律进行预测分析。结果 利用多因素磨削实验获得预测样本及对比样本,对比结果表明,预测模型的平均训练精度约为93.38%,预测精度为92.46%。螺杆转子砂带磨削表面粗糙度值的单因素预测结果表明,工件表面粗糙度值随着接触轮正压力及磨削装置轴向进给速度的增加而升高,随着砂带线速度及砂带粒度的增加而降低。结论 提出的算法可为选择螺杆转子砂带磨削的工艺参数提供理论依据。适当提高砂带线速度及砂带粒度、降低接触轮气缸压力及磨削装置轴向进给速度可获得较高的表面质量。     

超声振动砂带磨削TiC-TiB_2复合陶瓷的效率研究

本文采用超声振动砂带磨削的方法对超重力下燃烧合成的TiC-TiB2复合陶瓷进行磨削试验,寻求提高效率的途径和方法。通过与超声砂轮磨削和普通砂带磨削的对比试验,研究砂带种类、粒度及磨削工艺参数对磨削效率的影响规律,得出当磨削深度0.04 mm,砂带线速度15.2 m/s,工件进给速度1 000mm/min,金刚石砂带粒度60时,材料标准切除率较高。     

高速外圆磨削18CrNiMo7-6齿轮钢工艺参数优化

以18CrNiMo7-6齿轮钢为试验材料,采用正交试验法,研究高速外圆磨削加工中砂轮线速度、工件转速、砂轮径向进给速度和砂轮粒度等工艺参数对工件三维表面粗糙度幅度参数Sa、Sku和Ssk等工艺指标的影响。运用灰色关联分析方法对试验结果进行分析研究,将多项工艺指标的优化问题转化为单一目标灰关联度优化,以正交试验极差分析结果,得出最优工艺参数组合,即砂轮线速度90 m/s、工件转速90 rpm、砂轮径向进给速度0.1 mm/min、砂轮粒度W20。经过试验验证,该工艺参数组合能够有效获得更理想的表面质量。     

应用弹性砂轮对铝合金镜面磨削工艺研究

目的解决铝合金手机外壳传统抛光工艺中存在的抛光效率低等问题。方法采用聚氨酯弹性砂轮对6061铝合金进行了磨削加工,使用正交试验研究了磨料粒度、进给速度、切削深度、砂轮线速度对加工表面粗糙度及材料去除率的影响。试验中使用折线走刀方式进行加工,可减轻磨料分布不均带来的影响。使用白光干涉仪测量了加工后表面的粗糙度,通过计算单位时间内工件的质量变化得出了去除率,并通过对结果的综合优化得出了最优工艺参数。结果在选取的16组磨削工艺参数中,可获得的最低表面粗糙度为44.87 nm,最大去除率为0.329 g/min。对表面粗糙度影响最大的因素为磨料粒度,影响最小的因素为进给速度;对材料去除率影响最大的因素为切削深度,影响最小的为进给速度。经过综合优化,最佳工艺参数组合为:砂轮600#,转速2000 r/min,切削深度0.04 mm,进给速度20 mm/min。结论弹性聚氨酯砂轮应用于铝合金磨削可提高加工表面质量,可简化工艺流程,节省备料和安装调整时间,从而提高效率。     

金刚石薄圆锯片基体的磨削工艺参数优化

针对金刚石薄圆锯片基体磨削表面质量控制问题,在数控卧轴圆台平面磨床上开展圆锯片基体磨削正交试验,研究磨削工艺参数对其端跳、平面度、同片厚度差的影响规律。结果表明:砂轮转速对端跳影响最显著,提高砂轮转速有利于减小端跳;工作台转速对平面度以及同片厚度差影响最显著,提高工作台转速有利于获得平整和光洁的表面。优化的磨削工艺参数组合是砂轮转速为1 500 r/min,进给速度为3 000 mm/min,工作台转速为250 r/min,磁力为90%。在此参数下,对金刚石圆锯片基体进行磨削,其磨后的端跳、平面度和同片厚度差分别为0.08、0.02和0.004 mm,远小于标准规定的0.12、0.08和0.020 mm,且无明显磨削损伤缺陷。      

基于灰色理论的铁氧体切割工艺参数优化

针对铁氧体的高精度环形金刚石线锯切割工艺参数优化问题,以其切割后的面形精度和表面粗糙度作为评价指标,采用正交试验法研究主轴转速、进给速度和张紧力等工艺参数对切割表面质量的影响,并基于灰色理论对多工艺目标进行数据分析和综合评判,得到工艺参数组合优化方案为:主轴转速,1 000 r/min;进给速度,1.0 mm/min;张紧力,90 N。切割试验结果表明:用优化后的参数组合得到的面形精度PV为7.37 μm、表面粗糙度R_a为0.882 μm,加工表面质量提高,验证了铁氧体切割工艺参数优化的有效性和实用性。      

高速铣削航空铝合金的工艺参数优化研究

以6061铝合金为研究对象,在高速加工中心上对6061铝合金进行铣削加工,对加工后的工件表面粗糙度、材料去除率以及铣削力进行相应的测量和分析,通过切削加工实验的方法针对不同工艺参数组合方式以及不同刀具材料对加工效率和加工质量的影响情况展开研究,从而确定最优工艺参数组合以及最佳刀具材料。研究结果表明:硬质合金刀具的切削性能优于TIALN涂层刀具,当主轴转速为8000r/min,进给速度为1600mm/min,切削深度为0.2mm时,工件的表面质量最好,表面粗糙度Ra可达到0.14μm,同时材料去除率可以达到46310mm3/min,当主轴转速为8000r/min,进给速度为1600mm/min,切削深度为0.05mm时,铣削力分别是10N(X),11N(Y),7N(Z),该工艺参数组合可以提高刀具耐用度。     

弹性磨具磨抛M300曲面多目标磨削参数研究

目的通过M300模具钢曲面磨抛加工实验研究,解决传统抛光工艺效率低下等问题。方法采用弹性球头磨具对M300钢进行了曲面抛光加工,设计单因素实验和正交实验,研究主轴转速、磨具粒度、进给速度、切削深度等主要工艺参数对表面粗糙度与材料去除率的作用。使用Hilbert路径走刀方式进行加工,可均匀遍历整个待抛曲面,利用五轴加工中心作为试验平台,电子分析天平、三维表面形貌仪作为检测仪器,得到优化的工艺参数和优选区间。结果在9组选取的磨抛参数中,能够获得较为理想的表面粗糙度(0.078μm),材料去除率和磨耗比分别为2.152 mm3/min、0.07。对表面粗糙度影响较大的因素为切深,对材料去除率影响较大的因素为切深和进给速度。对于多目标优化,切深、主轴转速、进给速度、磨具粒度的影响程度逐次降低。优化后的工艺参数组合为:球头磨具320#,主轴转速4500 r/min,切深0.4 mm,进给速度80mm/s。结论采用弹性球头磨具磨抛可提高M300模具钢的材料去除率,改进加工表面质量,进而提高加工效率。     

微粉金刚石钎焊砂轮磨削氧化铝陶瓷的磨削力和表面粗糙度特征

在不同磨削深度、砂轮转速和进给速度组合下,研究微粉金刚石钎焊砂轮磨削氧化铝陶瓷过程的磨削力及工件的表面粗糙度的变化规律,并筛选出低磨削力和低工件表面粗糙度的加工工艺参数。试验结果表明:在微粉金刚石钎焊砂轮的磨削过程中,氧化铝陶瓷主要通过脆性断裂的方式去除;随着磨削深度、进给速度的增加,砂轮在进给方向和切深方向的力以及工件表面粗糙度都上升;随着砂轮转速的增加,进给方向和切深方向的力以及工件表面粗糙度都下降。试验获得的低磨削力和低工件表面粗糙度精密加工工艺参数分别为:磨削深度为1.0 μm,进给速度为12 mm/min,砂轮转速为24 000 r/min和磨削深度为1.0 μm,进给速度为1 mm/min,砂轮转速为20 000 r/min。低磨削力磨削时,微粉金刚石钎焊砂轮受到的X方向和Z方向的磨削力分别为0.15 N和0.72 N;精密加工后的氧化铝陶瓷的表面粗糙度值可达0.438 μm。      

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.