基于响应曲面法的MQL辅助切削钛合金的工艺参数优化

为了提高切削质量，减少刀具磨损，采用响应曲面法对最小微量润滑辅助切削的主要工艺参数进行优化。以钛合金TC4为切削对象，把工件表面粗糙度和刀具磨损作为评价指标，采用Minitab设计切削速度、进给量、喷射压力三因素的Box-Behnken试验。利用方差和拟合残差概率分布分析三因素的显著性及交互作用，并结合试验检验所建表面粗糙度和刀具磨损二阶响应预测模型的有效性。响应曲面法优化后的最佳工艺参数为切削速度25 m/min、进给量0.103 mm/r、喷射压力0.1 MPa，此时得到的表面粗糙度和刀具磨损量分别为1.195、151.9 μm，与预测值的误差分别为5.1%、2.91%。说明基于响应曲面法的微量润滑辅助切削钛合金表面粗糙度和刀具磨损量预测模型准确有效。     

基于灰色关联理论的空冷辅助车削钛合金端面的工艺参数优化

以TC4钛合金棒料为试验对象,以数控车床作为试验平台,对空冷辅助车削钛合金端面的切削速度、背吃刀量、进给量等主要工艺参数进行正交试验研究。采用灰色关联分析法,对工件表面粗糙度、刀具磨损量以及工件表面硬度等工艺目标进行综合评价,使多工艺目标转化为单一考察指标,得到了最佳的工艺优化组合方案,并提高了试验效率。研究结果证明:用灰色关联分析法优化后的工艺参数能够有效降低工件表面粗糙度,减少刀具磨损,使工件硬度更符合切削要求。     

45~#调质钢车削表面粗糙度研究

为提高数控车削45~#调质钢的加工表面粗糙度,基于正交试验法和单因素试验法设计车削试验,通过极差和方差分析法对试验结果进行分析,研究切削用量三要素(切削速度、进给量和背吃刀量)对加工表面粗糙度的影响。结果表明:影响车削加工表面粗糙度的显著性参数依次为切削速度背吃刀量进给量;单因素试验法分析结果表明加工表面粗糙度随切削速度的增加而降低,随进给量和背吃刀量的增加而增大。     

QSn7-0.2锡青铜连杆衬套车削加工参数优化

以强力旋压加工后的锡青铜连杆衬套为研究对象,采取田口试验优化算法研究了切削速度、进给量和背吃刀量对连杆衬套表面粗糙度的影响。通过设计正交试验表对精车后衬套表面粗糙度进行测量并且对比精车后轮廓算术平均偏差Ra和微观不平度10点高度偏差Rz的信噪比极差值,然后分析这3个加工参数对于刀具寿命的影响,最后得到了3种参数对于表面粗糙度的影响程度为:进给量切削速度背吃刀量,以及传统经验取值范围内的最优参数组合:车削速度为190mm/min;进给量为0.04mm/r;背吃刀量为0.2mm。     

PCD刀具加工氮化硅陶瓷孔的试验研究

使用PCD刀具对氮化硅陶瓷内孔进行切削试验,首先研究氮化硅陶瓷材料的去除机理,主要包括脆性去除和塑性去除,且以脆性去除为主。其次,研究刀具前角、切削速度、背吃刀量和进给量对切削力的影响。结果表明:刀具前角对切削力的影响不明显;随切削速度、背吃刀量和进给量的增加,切削力均增大,且背向力大于进给力和主切削力。最后,重点研究各参数对内孔侧壁表面粗糙度的影响。结果表明:进给量对表面粗糙度的影响最显著,其次是背吃刀量和切削速度,刀具前角几乎没有影响,且当刀具前角为-5°,切削速度为32.97m/min,背吃刀量为0.10mm,进给量为0.08mm/r时,可以得到较好的表面粗糙度和刀具寿命的综合效益。      

γ-TiAl合金铣削加工表面粗糙度研究

γ-TiAl合金因具有良好的高温物理和力学性能而广泛应用于航空航天、汽车等领域。通过γ-TiAl合金铣削加工正交试验,分析了切削参数对加工表面粗糙度的影响规律。研究表明:γ-TiAl合金铣削加工表面粗糙度的重要影响因素为背吃刀量和每齿进给量,其次是切削速度;切削速度、背吃刀量、每齿进给量之间的两两交互作用对表面粗糙度的影响不显著;表面粗糙度随着背吃刀量和每齿进给量的增加而增大,随着切削速度的增加先增大后减小。利用偏最小二乘回归法建立了基于切削参数的表面粗糙度的数学预测模型,通过模型的相关性分析以及F检验,验证了该模型具有较好的精度,能够满足表面粗糙度的一般性预测要求。在此次试验条件下获得最小表面粗糙度的切削参数为切削速度v_c=40 m/min、每齿进给量f_z=0.005 mm/z和背吃刀量a_p=0.05 mm。     

300 M超高强钢车削加工表面质量

目的研究切削参数对300M超高强度钢加工表面质量的影响。方法选用硬质合金刀具车削加工300M超高强度钢,研究切削参数对表面加工硬化、残余应力及表面粗糙度的影响。通过HXD-1000显微硬度检测仪、X-350A型X射线应力测试系统、TR240表面粗糙度测量仪对实验过程进行检测分析。通过单因素试验研究影响表面粗糙度的主次因素,并通过正交试验,以进给量f、切削速度v、刀尖圆弧半径rε、背吃刀量a_p为变量建立表面粗糙度的预测模型。结果背吃刀量a_p=0.2 mm,切削速度v为60~120 m/min,进给量f为0.1~0.25 mm/r时,300M钢经切削加工后,维氏硬度在467~550HV范围内变化。切削速度从60 m/min增大至200 m/min时,表面残余应力从压应力-59.13 MPa变为拉应力257.33 MPa,次表层残余应力的最大残余压应力从-147.46 MPa增大到-422.65 MPa,并且层深至50μm左右处,工件材料的加工变质层结束。结论表面硬度随着进给量和切削速度的增大而减小,并且越往里层,硬度越低,直至达到基体的硬度。影响表面粗糙度的最主要因素为进给量,其次是刀尖圆弧半径,再次为切削速度,背吃刀量对表面粗糙度的影响最小。建立的表面粗糙度预测模型通过了试验验证,具有很高的加工精度。     

Al2O3-TiCN涂层硬质合金刀具干切削N型HT250灰铸铁表面粗糙度研究

基于正交试验,采用Al_2O_3-TiCN涂层硬质合金刀具干切削N型HT250灰铸铁,研究切削速度、进给量和背吃刀量对表面粗糙度的影响及机制,为N型HT250的切削提供理论依据。结果表明:Al_2O_3-TiCN涂层硬质合金刀具切削N型HT250的表面粗糙度优于普通HT250,尤其在低切削速度(v_c=100 m/min)的情况下,N型HT250表面粗糙度更具优异性;对N型HT250表面粗糙度影响最显著的因素是进给量,其次是背吃刀量,切削速度对表面粗糙度的影响程度相对较小;表面粗糙度随着进给量的增加而显著增加,随着背吃刀量的增加先减小后增大,当a_p=1 mm时,表面粗糙度综合表现最佳。     

切削用量对镍基高温合金GH4169表面粗糙度试验研究

文章在单因素条件下进行了车削GH4169的表面粗糙度试验,得到了切削用量(切削速度、进给量、背吃刀量)的改变对表面粗糙度Ra、Rmr(c)的影响规律,分析了所导致表面粗糙度变化的原因。试验结果表明:表面粗糙度值Ra的影响程度从大到小依次为进给量、切削速度和背吃刀量。Ra值随着进给量的增加呈线性增大,Ra值随着切削速度增大呈先减小后增大,Ra值随背吃刀量的增加而缓慢增大。背吃刀量对粗糙度轮廓的支承长度率Rmr(c)的影响最大,切削速度次之,进给量影响较小。     

基于响应面法的环网柜接线套管干切削工艺参数优化研究

采用干切削加工是修复环网柜接线套管表面烧蚀、裂痕的一种有效方法。利用单因素试验研究切削用量在未涂层、TiAlCrN涂层和TiAlSiN涂层刀具下对切削力的影响规律。在单因素试验的基础上运用Box-Behnken中心组合试验方法,采用性能最优的TiAlSiN涂层刀具对环网柜接线套管切削工作参数进行试验研究,以切削速度、进给量和背吃刀量为试验因素,以刀具切向力、轴向力、径向力为试验指标进行三因素三水平二次旋转回归正交试验。通过建立响应面数学模型,分析各切削工艺参数对切削性能的影响,并对试验因素进行综合优化。试验结果表明：影响切削力显著顺序为背吃刀量＞进给量＞切削速度;最优参数组合为切削速度94.589 m/min、进给量0.097 mm/r、背吃刀量0.501 mm,此时刀具切向力为11.75 N、轴向力为34.80 N、径向力为19.53 N;验证试验结果与理论优化值基本吻合。     

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.     

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.     

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.     

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.