板形检测控制新方法

介绍了国内外最新的板形检测和控制技术,分析了几种新型的板形检测和控制方法及其应用状况,并结合板带产品的发展及要求展望了未来板形检测与控制的发展方向.     

Sources of variability in laboratory rock test results

Appropriate rock characterization is beneficial in providing a reliable judgment on rock properties which is crucial for the design process of rock engineering applications. However, it can be difficult to obtain consistent mechanical parameters due to substantial variations in rock properties. In this research,uniaxial compression tests on dolerite specimens collected from a gold mine in Western Australia showed substantial scatter in the results. Rock categorization based on the P-wave velocities is as accurate as the thin section analysis, which suggests that they can be used together to gain a more accurate initial understanding of the rock types before any laboratory testing. The quality of specimen preparation and rockemachine interaction greatly affect the test results. For instance, non-parallelness of loading platens can lead to considerable scatter of the testing results, which would be perceived as rock variability. It is suggested that the current testing standards should be modified towards a better control of the loading machine performance and equipment precision. Finally, the possibility of pre-existing microcracks in rock, neither detected by the thin section analysis nor by the ultrasonic measurement,must be examined by computed tomography(CT) scanning as they can affect the test results. This study will enhance our knowledge about the sources of variability in laboratory test results of rock which is essential for obtaining reliable data.     

浅谈如何有效提高高速公路沥青路面平整度

针对高速公路沥青路面平整度的重要性,分析了施工中影响沥青路面平整度的因素,提出了提高高速公路路面平整度的措施,以达到优良的路面平整度,提高道路工程的社会效益和经济效益。     

倒置保温层铝板轻质屋面施工新技术

倒置保温层铝板轻质屋面是以优质轻钢龙骨作为骨架,以铝板作为面板,并在面层铝板和底层铝板之间填充玻璃保温棉且面层铝板具有氟碳漆表面涂层的新型节能屋面.介绍了该施工技术的特点和原理,详细阐述了屋面的施工工序,提出了质量控制和产品保护措施,与传统施工方法相比,该技术针对倒置保温层铝板轻质屋面施工工法的研究进一步提出屋面的平整度控制、保温隔热性能的持久稳定性、提高屋面防水、泄水性能等施工措施,从而大大延长了产品的使用年限等创新研究内容.最后对该技术进行了总结.应用结果表明,该屋面系统具有质量轻、强度高、防水、保温性能好等特点,工程质量得到保证,提高了经济效益.     

H2/Ar流量比对纳米金刚石形貌和结构的影响

目的研究不同H_2/Ar流量比对纳米金刚石形貌和结构的影响。方法采用MPECVD法制备了质量较好的纳米金刚石薄膜,并通过SEM、XRD对金刚石薄膜的形貌、结构以及晶粒尺寸进行了测试,还使用Raman对金刚石D峰、纳米金刚石特征峰(TPA)的变化趋势进行了分析。结果当Q(H_2):Q(Ar)=50:49时,制备的金刚石晶粒为亚微米范畴,其平均晶粒尺寸为250 nm,表面平整度较差,出现堆积层错现象,但金刚石特征峰(D峰)最强,生长速率达到最大,约为125 nm/h;Q(H_2):Q(Ar)=10:89时,表面平整度高,二次形核现象明显,平均晶粒尺寸为20 nm;进一步减小H_2/Ar流量比为0时,可发现晶粒由纳米变为超纳米,二次形核更为明显,表面平整更高,其平均晶粒尺寸为3 nm,另外Raman测试发现金刚石特征峰强度随H_2/Ar流量比的减小而减小,而纳米金刚石特征峰随H_2/Ar流量比的减小而增大。结论随着H_2/Ar流量比的增加,金刚石表面平整度逐渐变差,表面粗糙度也在逐渐增大,同时金刚石的晶粒尺寸和生长速率在Q(H_2):Q(Ar)=50:49时达到最大。     

中厚板在矫直后的残余应力分布分析

残余应力是影响矫后中厚板平直度的主要因素.通过有限元软件ANSYS/LS-DYNA对中厚板矫直过程的模拟,揭示了轧件矫后在长度、宽度方向上不同的纵、横向残余应力分布状态,提出了矫直辊应采取相应的调整方案,以使残余应力的分布均匀化.     

An optical flatness measurement system for medium-sized surface plates

This paper describes the work to develop a parallel beam scanning system (PBSS) for the noncontact measurement of surface flatness of such medium-sized surface plates, as sheet metals, sheet-moulding compound (SMC) plates, and glass plates, which are difficult to measure by traditional methods. The PBSS consists of a He---Ne laser source with good pointing stability, a scanner to create divergent scanning beams, a large aplanatic meniscus lens to convert the divergent beams to parallel beams, a linear stage to drive the testpiece to each sampling position, a screen for the projection of reflected beams from the tested surface, and an image-processing unit to analyze the projected image. Because of the out-of-flatness of the surface, the straight line formed by the incident parallel beams will be distorted and magnified on the screen as it is reflected from the surface. A charge-coupled-device (CCD) camera is employed to capture the image of the distorted line each time, and proceeds in line-by-line sequence. With the proposed mathematical model, the three dimensional (3-D) flatness data of the testpiece can be converted from the input image data and analyzed by the least-squares method. Experimental results by the use of this system have shown good agreement with the results obtained from a coordinate measuring machine (CMM). Because of the limit of the meniscus lens, the workpiece size is within 200 mm in width.     

平面度坐标测量的不确定度计算

目前的坐标测量只是给出平面度最小二乘检验的结果,并没有给出检验结果的不确定度.根据平面度最小二乘检验的基本原理和ISO/TS 14253-2给出的不确定度传递公式,提出了一种平面度坐标测量的不确定度的计算方法.该方法的特点是将平面方程的系数看作一个随机向量,通过计算该随机向量的均值和协方差矩阵来确定平面方程和平面度的检验结果及其不确定度.这不仅保证了平面度检验结果的完整性,而且符合新一代产品几何规范(GPS)标准的要求,从而可以提高工件检验的准确性.实验结果表明,根据平面度最小二乘检验的结果及其不确定度,可以根据ISO 14253-1给出的判定原则定量地判定平面是否合格.     

冷轧带钢倾斜浪缺陷产生机理分析及控制研究

冷轧带钢倾斜浪缺陷即带钢表面斜纹是冷连轧产品普遍存在的一种板形缺陷,其产生机理及调控手段尚不清楚。介绍了倾斜浪缺陷的特征;进行了轧制规程调整、轧机设备精度调整等轧制试验。结果表明,双边浪轧制和调节五机架前后张力对倾斜浪缺陷有较为明显的影响。综合理论分析和试验结果,认为轧机出口带钢横断面张力不均,造成张力大的部分条元延伸率大,即造成带钢横断面的金属纵向延伸率不同,不能均匀纵向流动,且产生横向流动,各条元之间产生相互作用的内应力,当内应力足够大就会引起带钢翘曲;此条元的带钢翘曲后,张力变小,相邻条元的张力变大,带钢翘曲沿着带钢纵向斜的方向移动,便产生了倾斜浪缺陷。为此,提出了采用双边浪轧制和调整五机架前后轧制张力共同抑制倾斜浪缺陷的方法,试验结果表明倾斜浪缺陷改善明显。     

基于层叠式夹持超薄蓝宝石晶片双平面加工实验研究

目的 针对超薄蓝宝石晶片的双平面加工,研究基盘表面高度差对工件平面度的影响,确定双平面加工超薄蓝宝石晶片的有效性.方法 通过多种方式得到具有不同表面高度差(高度差分别为5.3、9.8、19.9、29.7μm)的基盘,利用层叠式夹持方法对超薄蓝宝石晶片进行夹持(厚度0.17 mm)并进行双平面加工,获得不同高度差下的工件...