盲孔的滚压加工和工具

本文介绍了一种新的滚压工具,其结构简单,通用性强,一种工具可加工多种不同孔径的工件,并可加工至盲孔孔底,而不需要退刀槽。由于有色金属磨削困难,因此这种滚压工具对有色金属的加工更具有特殊意义。     

轴承套圈冷辗扩加工技术

冷辗扩是一种适用于旋转体的先进加工工艺,详细地探讨了冷辗扩加工的关键问题及发展方向。     

车轴滚压刀具的设计和滚压工艺试验分析

动车组车轴运行时,在车轴圆角处容易产生疲劳损坏,严重时导致车轴断裂。为强化车轴表面,针对动车组EA4T车轴设计了滚珠滚压刀具,完成对滚压刀具元件的设计和选择,通过滚压试验分别得出滚压力、进给速度和车床主轴转速为参数变量时对车轴表面质量的影响规律。     

Metalworking fluids and nitrosamines

The USA Environmental Protection Agency has issued a regulation prohibiting the use of nitrite in any cutting fluid containing a triethanolamine salt of a tricarboxylic acid. This is the first time that the Agency has placed any restriction on the composition of cutting fluids. The authors comment on the regulation and review the literature concerning nitrosamines as they pertain to cutting fluids.     

热轧带钢轧制力的研究与模拟分析

综合考虑了轧辊弹性变形与轧件弹塑性变形,运用影响函数法进行热轧带钢轧制力计算,采用VC++9.0应用程序编写了轧制力计算软件,同时建立了四辊轧机轧制过程的三维有限元模型,对比验证了此轧制力计算模型的正确性。     

曲轴深滚压工艺及滚压力异常分析和处理

曲轴作为典型的非均质结构零件,尺寸过渡处存在应力集中。研究和实践表明,曲轴的疲劳破坏大多发生在曲柄与主轴颈、连杆轴颈的过渡圆角处。为了提高其抗疲劳强度必须对曲轴的这些部位实施滚压强化工艺。结合曲轴圆角滚压强化和校直系统,对德国Hegenscheidt圆角滚压校直机床的原理、滚压工艺以及滚压校直过程中滚压力的变化进行研究．并对滚压力异常进行分析。     

螺纹的滚压加工

螺纹滚压加工就是用滚压工具进行挤压,使金属塑性变形而形成螺纹的方法。滚压螺纹的金属纤维是连续的,而切削螺纹的金属纤维是断开的,因而滚压螺纹具有如下优点：　　①螺纹表面质量较好,表面粗糙度值较低;　　②提高被加工件表层金属的硬度和强度,特别是牙底表面硬度有很大提高;　　③经济效果比切削螺纹提高工效几倍至几十倍,易于实现自动化;　　④滚压螺纹是无屑加工,可节省原材料;　　⑤可加工无法用切削方法加工的细长螺杆。　　正是由于滚压螺纹具有以上优点,因此螺纹滚压加工得到广泛应用。但是在螺纹滚压加工中一付…     

Synthetic fluids between synthetic hydrocarbons and ester fluids: Co-oligomers of alphaolefins and alkylmethacrylates

Through co-oligomerisation of alphaolefins with alkylmethacrylates, fluids are obtained with a unique chemical combination of non-polar PAO and polar ester oil in one molecule. The polarity of these co-oligomers between P A 0 on the one hand and ester oil on the other helps to avoid the typical disadvantages of these common synthetic base oils. Thus, co-oligomers offer superior solvency for DI packages, neutral elastomer behaviour, the hydrolytic stability of sterically hindered esters, a thermal and oxidative stability close to PAO, and free miscibility with mineral oil and synthetic base stocks. Co-oligomers are Newtonian fluids of high purity and with a viscosity range between 50 and 600 mm²/s at 100°C. Both viscosity level and purity open up a range of applications. Even without high molecular weight VI improver, gear oils, and hydraulic oils with outstanding viscometric performance can be formulated. The purity has a positive influence on properties such as demulsibility, de-aeration, and foaming behaviour. The present paper compares co-oligomers with common base fluids and gives examples of typical applications.     

滚动轴承对滚动体的技术要求

滚动轴承的精度、性能和寿命,在很大程度上取决于滚动体的技术质量水平。从轴承的基本要求出发,对滚动体在尺寸规格、公差等级、力学性能、疲劳寿命、振动噪声等方面如何满足其适用性进行了概括,同时对国产滚动体的技术质量水平现状进行了评述。     

热轧带钢还原冷轧后的表面及横截面形貌

对Q215热轧带钢试样进行还原处理后,利用四辊轧机对其进行五道次冷轧试验,采用扫描电镜对还原后及不同道次冷轧后试样的表面和横截面形貌进行了观察。结果表明:还原后热轧带钢表面出现的裂纹、气泡和气孔等缺陷在冷轧过程中得到有效消除,裂纹宽度减小并趋于闭合,但五道次冷轧后,带钢表面仍然残留裂纹痕迹,且裂纹间距增大;带钢表面脱碳层厚度逐道次减小,试样表面形貌得到改善,表面质量不断提高。     

滚动导轨及其设计

概述了滚动导轨的特点、应用和常用的材料,并介绍了其结构和工作原理及其设计的有关参数的确定。     

High-temperature hydraulic fluids

The rationale is presented for the development of 315 °C bulk oil high-temperature hydraulic fluids for future US Air Force systems. Four chemical classes of candidate fluids worthy of consideration are described along with their relative merits and limitations. The four fluids are: mineral oil based MIL-H- 27601A, a synthetic hydrogenated polyalphaolefin, a synthetic silahydrocarbon (tetra alkyl silane), and a linear perjluoropolyalkylether. Questions for consideration in selecting a candidate high-temperature hydraulic fluid are presented and discussed in relation to the intended specific application.     

热轧带钢终轧温度控制系统的改造与应用

针对莱钢1 500热连轧终轧温度控制精度低的现状,对机架间冷却水控制系统进行了研究与改造。首先对电动调节阀进行重新测试,然后对机架间冷却数学模型和终轧温度控制的实际应用进行了深入的理论研究。在基础自动化控制系统的改造中,增加了分档式反馈控制和前馈控制;同时在过程自动化控制系统中对预设定计算模块进行了优化。经过现场一年多的运行,改造后的系统大大提高了带钢终轧温度的控制精度和带钢成品的质量,具有很好的应用价值。     

卷取和翻转过程薄膜牵引和卷取同步控制研究

采用转速和张力的闭环控制.在给定的线速度下,协调控制牵引电机和卷取电机的转速,实现卷取电机转速跟随牵引电机的转速变化.转速的控制和张力的控制都采用PID控制.     

冷轧铝板带材轧制油起泡的原因及对策

通过分析冷轧铝板带材轧制过程中轧制油起泡对产品质量的影响,阐述了轧制油起泡的原因,并提出了针对轧制油起泡的对策.轧制油的皂化、因氧化引起的轧制油质量下降、混入其它油品和设备原因是引起轧制油起泡的主要原因,可分别采用添加消泡剂、过滤水分和杂质、保证轧制油循环过滤系统的正常运行等措施来消除因氧化引起的轧制油质量下降、轧制油的皂化和设备原因等引起的起泡.     

柳钢小轧厂一火成材工艺及设备的改造

介绍广西柳钢小型轧钢厂实施连铸坯一火成材工艺及设备改造的利与弊