铝合金筒段化学铣切工艺研究

对2219铝合金筒段的化学铣切工艺进行了研究,以确定化学铣切工艺的最佳配方和工艺控制要点.对NaOH、Na2S、三乙醇胺(TEA)和溶解Al正交试验的结果进行了验证性试验,确定了对化学铣切表面粗糙度的影响程度依次为:Na2S、溶解Al、TEA、NaOH,化学铣切溶液的最佳配方为:75～150 g/L NaOH, 6～15 g/L Na2S, 38.5～42.0 g/L TEA,溶解Al 32.5～120.0 g/L.按该配方对2219铝合金筒段进行化学铣切,可达到最佳效果:表面粗糙度1.2～1.4 μm、化学铣切壁厚公差≤0.12 mm、化学铣切轮廓线线偏离≤0.75 mm.     

2A97铝锂合金化学铣切工艺探讨

2A97铝锂合金是我国自主研发的新型高强铝锂合金,在航空航天等领域具有很好的应用前景,目前对其进行化铣的研究不多。在传统铝合金碱性化铣溶液体系基础上,通过响应曲面法优化2A97铝锂合金化铣液配方,并在单因素试验的基础上考察氢氧化钠、铝离子浓度对化铣表面质量的影响规律。结果表明:化铣液的配方为氢氧化钠140.0 g/L、硫化钠40.0 g/L、三乙醇胺50.0 g/L、铝离子70.0 g/L时,可获得较好的综合性能;随着氢氧化钠浓度的增加腐蚀速度增加,当氢氧化钠浓度在130.0~150.0 g/L时粗糙度Ra小于1.6μm,氢氧化钠浓度对端晶腐蚀的影响无明显规律;随着铝离子浓度增加腐蚀速度下降、粗糙度明显减小,在不同铝离子浓度下端晶腐蚀没有明显的变化规律。     

GH4169高温合金化学铣切表面粗糙度的影响因素

为了满足生产对GH4169高温合金化学铣切加工表面粗糙度的要求,通过单因素试验研究了化铣液的主要成分和化铣工艺参数对GH4169高温合金表面粗糙度的影响。结果表明:随着化铣液中FeCl3和HNO3浓度的升高,表面粗糙度呈下降趋势;当化铣液温度高于50℃时,表面粗糙度在1.4μm以下;HCl,HF浓度均为200 mL/L时,表面粗糙度最小;添加剂SA和SN能够降低表面粗糙度和消除凹槽;随着化铣液中Ni2+浓度的增加,表面粗糙度也随之变大,当Ni2+浓度大于26.95 g/L时,表面粗糙度达到1.6μm以上,不符合加工要求;最佳化铣工艺为200～250 g/L FeCl3,200 mL/L HF,150 mL/L HNO3,200 mL/L HCl,0.2 g/L添加剂SA,0.5 mL/L添加剂SN,温度53℃,该工艺下化铣的GH4169高温合金表面质量良好,无凹槽、沟蚀,表面光洁,粗糙度小于1.6μm,符合生产要求。     

2197铝锂合金碱性化铣液中Al3+浓度对化铣表面质量的影响

铝锂合金有望在航空航天领域广泛使用,常对其进行化铣加工.目前,尚未见关于化铣液中Al3+如何影响铝锂合金化铣表面质量的详细报道.研究了碱性化铣液中Al3+浓度对2197铝锂合金化铣加工速率、表面粗糙度、浸蚀比及加工精度等的影响.结果表明:随着化铣液中Al3+浓度增加,化铣速率不断下降,当化铣速率低于20 μm/min时,槽液失效;化铣试样表面粗糙度和浸蚀比均随Al3+浓度增加呈不断下降趋势,Al3+浓度过低或过高均不利于化铣;A13+浓度的增加对加工精度的影响不大,铝锂合金的初始化铣液中含有一定量的Al3+浓度对化铣有利;综合考虑,化铣时适宜的Al3+浓度为20～60 g/L.     

高表面粗糙度6061铝合金的两酸抛光工艺研究

目的 为了降低6061铝合金的表面粗糙度,提出了一种环保型的两酸化学抛光工艺,并探究了抛光工艺条件对6061铝合金表面粗糙度和表面形貌的影响。方法 采用正交实验设计,确定6061铝合金两酸抛光添加剂的浓度,在此基础上通过单因素实验进一步对抛光液配方、温度和时间进行参数优化。通过粗糙度仪测量抛光前后的粗糙度和表面轮廓曲线,利用金相显微镜观察抛光前后的微观表面和断面金相,并且计算最佳工艺下的失重率。结果 在温度100 ℃、抛光10 min条件下,当抛光液的成分为H3PO4+H2SO4(质量比为2︰1)、10 g/L硫酸铝、2 g/L硫酸铜、1.6 g/L金属盐A、3 g/L氧化剂B、15 g/L过硫酸铵、1.5 g/L钼酸铵时,抛光效果最好。在最佳工艺下进行抛光,使铝合金表面粗糙度从6~8 µm降低至2 µm左右,粗糙度的标准差从2 µm左右降低至1 µm以下,失重率在0.002~0.004 g/(cm².min)范围内波动,并且得到了光亮的表面。结论 该抛光体系在处理高表面粗糙度的6061铝合金时表现出良好的抛光效果,研究结果对提高3D打印的6061铝合金零件表面质量提供了较好的借鉴与理论分析基础。     

初步研究316L不锈钢焊缝在含氢杂质的液态锂中的腐蚀行为

通过失重法、SEM/EDS、XRD和硬度分析等手段,研究了不同温度下316L不锈钢焊缝区在含0.15%H杂质的液态锂中浸泡500 h的腐蚀行为。实验结果表明,当腐蚀温度为450℃、560℃和720℃时,样品的平均腐蚀速率分别为2.38×10-3g·m-2·h-1、1.10×10-2g·m-2·h-1和1.86×10-2g·m-2·h-1。在焊缝表面上分别发现了晶界腐蚀,大量致密的尺寸为1~2μm的碳化物和少量尺寸为10~20μm的"类尖晶石"结构的碳化物。仅在720℃的腐蚀焊缝截面发现了明显的腐蚀相变层。焊缝表面的平均维氏硬度分别为HV114.05、HV98.52和HV91.65。总之,随着温度的升高,焊缝区腐蚀越严重。焊缝表面的碳化物与H杂质发生化学反应后溶解于液态锂中,加速了焊缝区在液态锂中的腐蚀。     

Pb-Sn-Cu合金共沉积工艺研究

为了改善内燃机滑动轴承镀层的减摩性能,采用在合金基体上镀覆三元合金的工艺,在氟硼酸盐镀液体系中实现了Pb-Sn-Cu三元合金表面电镀.研究了镀液体系中镀液成分及工艺参数对Pb-Sn-Cu三元合金镀层成分及含量的影响.结果表明,镀液成分及电镀工艺参数对镀层成分及含量有较大的影响.镀液成分及电镀工艺参数的试验结果表明,镀液的最佳组成及工艺参数为:200 g/L Pb2+,25 g/L Sn2+,2.5 g/LCu2+,4g/L对苯二酚,2.5 g/L蛋白胨,100 g/L游离HBF4,30 g/L H3803,温度为25℃,电流密度6.0A/dm2.     

碱性锌酸盐体系锌钴合金电镀工艺研究

目前国内对碱性锌酸盐体系电镀锌钴合金的研究较少。研究了碱性锌酸盐Zn-Co合金电镀体系中合金镀液组成及工艺条件对镀层Co含量的影响,得到了最佳镀液组成及工艺条件:锌钴离子总浓度0.3 mol/L,锌钴离子摩尔比9∶1,150 g/L氢氧化钠,15.0 m L/L添加剂A,1.0 m L/L添加剂B,电流密度Jc3 A/dm2,温度25~30℃。在最佳工艺条件下可得到Co含量为2.0%~2.2%的Zn-Co合金镀层。结果表明:Zn-Co金的沉积表现为异常共沉积;在一定范围内,镀层中钴含量的变化会影响镀层光亮度的变化;钴配位剂对Zn-Co合金的共沉积电化学行为不造成影响。     

镍基单晶铸件表面化学铣切的均匀性及深度

镍基单晶铸件加工性能差,对此采用化学铣切工艺进行加工。通过单一变量法确定了不同浓度硝酸、盐酸、氢氟酸的化学铣切速率及变化规律,用SEM分析了不同浓度硝酸、盐酸、氢氟酸对铣切试样表面均匀性的影响。结果表明:最佳铣切工艺为120 mL/L硝酸,150 mL/L盐酸,185 mL/L氢氟酸;温度30℃,铣切表面均匀性好,且有一定的深度,铣切过程稳定可控。     

无表面活性剂作载体的氯化钾(钠)体系光亮镀锌研究

酸性氯化钾镀锌主光亮剂载体为表面活性物质,常造成镀层质量下降并存在废水处理困难等问题。为此,在不含有任何表面活性剂作载体的酸性氯化钾(钠)镀锌液中进行光亮镀锌研究。在镀液中使用了新研制出的开缸剂、辅助剂和水溶性光亮剂,并运用Hull Cell、小槽电镀以及电化学方法,考察了镀液的各种性能。结果表明,在表面活性剂载体浓度为零的情况下,主光剂在镀液中溶解性能良好;在工艺及操作范围内,可得到均匀、柔性、平整、分散性好、全光亮的镀锌层;可节约用水50%以上,有利于水源、大气和土壤等环境保护;并可与现行的使用表面活性剂载体的镀锌液相互兼容。推荐的镀液成分和操作条件:Zn Cl260~75 g/L,KCl(NaCl)200~250 g/L,H_3BO_325~30 g/L,开缸剂30~40 m L/L(第一次使用时添加),辅助剂12~15 m L/L,光亮剂8~12 m L/L;pH值4.8~5.8,温度10~45℃,J_c=0.25~5.00 A/dm~2。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.