模具钢表面硬度的涡流无损表征方法

为了将涡流法应用于模具钢的表面硬度无损检测,从试验方法和传感器检测灵敏度分析2个方面展开研究.首先,采用不同热处理工艺,制备了硬度不同的45号钢和S136钢试样,得到了硬度与回火温度的关系曲线;其次,利用涡流测试系统(常规测试系统)对所有试样进行检测,将得到的阻抗幅值与试样硬度进行回归分析,结果表明:在45号钢中,阻抗幅值与硬度呈良好线性关系,而在S136钢中,阻抗幅值与硬度呈非线性关系;最后,对比分析了3种不同传感器对硬度的检测灵敏度,当线圈电感值越大时,检测灵敏度越高.另外,制作了另一种电磁传感器并搭建相关试验平台,对45号钢和S136钢试样硬度进行测试,测试结果与常规涡流传感器测试结果趋势一致,相互验证了试验方法和数据处理方法的可靠性.上述研究结论显示,涡流检测可以实现模具钢硬度的快速、无损检测,测试方法和系统有望应用于工程实际.     

移动式钢轨焊接接头表面硬化装置及工艺的研究

介绍了所研制的移动式钢轨焊接接头表面硬化处理装置的结构、功能与使用方法.利用该装置对U71Mn和U75V钢轨焊后轨头表面硬化处理（即欠速淬火）试验.分别进行化学成分、硬度以及显微组织分析.结果表明：处理后的钢轨接头,具有较理想的显微组织和更为合适的轨顶硬度;可以成功地对钢轨焊接接头进行在线热处理,满足线路现场施工的热处理工艺要求.     

Effect of alternate magnetic field on LY12 structure properties after thermal plastic forming

The powerful alternate magnetic field treatment is an effective not-heat treatment, which improves the coriaceous performance of the material. In order to reveal the effect rule of the powerful alternate magnetic field on the structure capability after thermal plastic forming, the experimental methods were adopted to compare the microcosmic structure of the LY12 aluminium alloy test pieces before and after the powerful alternate magnetic field treatment. The mechanism of the structure refining was analyzed theoretically. According to the effect rule of the alternate magnetic field on critical grain growth work and the magnetic vibration-constriction mechanism, the structure dynamics factors were analyzed. The results show that, after a certain powerful alternate magnetic field treatment, the mechanical capability of the LY12 aluminium alloy after thermal plastic forming can be reinforced, the structure intertwist deriving from the thermal plastic forming becomes even and the branch crystal is also smashed, consequently refines the structure. The powerful alternate magnetic field treatment can be regarded as an effective method to improve metal structure performance after heat plastic forming.     

钢铜摩擦副表面粗糙度,硬度对摩擦磨损性能的影响

本文利用双圆盘滚子试验机,研究了钢铜摩擦副试件表面粗糙度、硬度对摩擦磨损性能的影响机理。通过形貌仪和显微镜的检测,分析了不同硬度条件下,表面粗糙度的作用效果。同时,还在扫描电镜上分析了硬度影响曲线的突变状态,提出了在现有生产加工条件下,减少钢铜摩擦副(主要指蜗杆传动副)磨擦,降低磨损的几个有效途径。     

翡翠粉体成型工艺研究

利用天然缅甸翡翠边角料及杂质较多低档翡翠进行粉体法翡翠再造，对影响翡翠色泽、硬度、致密度等因素进行了研究．结果表明：通过磁选的方法可去除内部翡翠影响透明度的弱磁性的闪石和含铁矿物，含铬硬玉中Cr^3＋在热扩散过程中使颜色分布均一，无铅硼酸盐玻璃的添加使SPS烧结能达到理论致密度的96％．烧结样品的硬度高于天然翡翠，X射线分析表明存在部分物相转变，压力和快速烧结有利于抑制相变．     

基于图象处理的布氏硬度测试系统研究

布氏硬度压痕直径传统的测量方法是用20倍的读数显微镜,效率较低,误差较大。为了提高布氏硬度测试的效率和精度,利用OpenCV软件强大的运算和图形图像处理功能开发了基于图象处理的布氏硬度测试系统。可实现布氏硬度的自动测试和结果的自动显示,而且界面友好简单,操作方便可靠。实验结果表明,基于图象处理的布氏硬度测试系统大大提高了测量结果的准确性,提高了效率,且结果可以保存。     

扫描电镜下摩擦磨损行为的原位动力学研究

摩擦磨损行为的ＳＥＭ原位动力学研究装置是国外７０年代末才发展起来的动态微观手段。本文详细地对比介绍了国外最具代表性的８种ＳＥＭ原位动力学研究装置各自开展的研究工作，同时亦具体介绍了一台用国产台式扫描电镜改装而成的滑擦磨损试验装置，这台装置的主要优点是既可对摩擦磨损过程作动态观察也可作准动态观察。这两种观察方法对研究摩擦损过程是同等重要的，该装置已用来对Ｎｉ－Ｐ化学镀有Ｎｉ－ＰＴＥＥ和Ｎｉ Ｐ－ＳＩ     

离合器齿毂总成焊接强度试验

为了确保离合器齿毂总成的安全,需要分析离合器齿毂和离合器内架的焊接强度.根据现有的离合器齿毂总成,设计其台架试验所需夹具,参考企业和试验要求,选择了3个试件总成,对离合器齿毂总成进行了焊接强度试验.试验结果表明:3个试件失效形式为离合器齿毂和离合器内架焊缝连接处撕裂,承载能力均能满足强度要求,离合器齿毂总成满足设计的要求.     

新型电磁无损检测仪的研制

简述了基于初始磁导率法的新型电磁无损检测仪的检测原理,用该仪器进行了测试,测得４０Ｃｒ结构钢的硬度与仪器数显值成单值关系,从而解决了目前国内外各种电磁检测仪的指示值与硬度之间成“Ｎ”型关系的一大难题。     

长货架期软面包质构的测定方法

对长货架期软面包质构的测定方法进行研究．首先选用探头P／2测定面包皮硬度，探头P／6测定面包芯硬度，探头P／0．5测定面包芯硬度及新鲜度．由测定结果的稳定性筛选探头后，应用探头P／0．5测定面包贮存期间质构变化，分析比较测定结果与感官评价结果相关性．实验结果表明：以探头P／0．5所测硬度指标作为面包新鲜度的客观评价值最为科学，每个样品的变异系数为10．76，贮藏期实验中，与面包新鲜度的感官评价结果相关性系数达到0．9258．     

强流脉冲电子束对3Cr2W8V微摩擦磨损性能的影响

分别制备了常规热处理、强流脉冲电子束直接处理和强流脉冲电子束合金化Al处理的3Cr2W8V模具钢试样,使用金相显微镜、表面粗糙度测试仪,硬度测试仪对处理层的显微结构、表面粗糙度及截面硬度进行分析,采用HSR-2M微摩擦磨损试验机对处理层摩擦磨损性能进行测试。结果表明:试样原始表面粗糙度的大小对处理后粗糙度的影响较大;电子束处理后截面硬度均有所提高,其中3Cr2W8V电子束合金化Al的峰值硬度相对于原始样品升高了10%,而3Cr2W8V电子束直接照射样品的峰值硬度相对于原始样品升高了24%～33%;经电子束照射后的试样在微摩擦实验中摩擦系数均出现突然增大现象,增大后的摩擦系数与原始样品相当。3Cr2W8V电子束合金化Al样品、3Cr2W8V电子束直接照射样品的磨损量相对于原始样品分别下降22.7%、72.7%。     

Effect of optimal aging treatment on magnetic performance and mechanical properties of sintered Nd-Fe-B permanent magnets

The magnetic performance and mechanical properties including hardness, brittleness, fracture toughness and strength characteristics of the as-sintered and the optimal aged Nd-Fe-B magnets were examined in this work. A new method of Vickers hardness indentation combined with acoustic emission was used to test the brittleness of the magnets.The results show that the magnetic properties of the magnets could be improved through aging treatment, especially the intrinsic coercive force. But it is accompanied by a decrease of strength and fracture toughness. Theoretical calculation confirms that acoustic emission energy accumulated count value could be used to characterize the material brittleness. The bending fracture morphologies of the as-sintered and the optimal aged Nd Fe B magnets were investigated with the emphasis on the relationship between mechanical properties and microstructure using a field emission scanning electron microscopy(FE-SEM). The research results indicate that the intergranular fracture is the primary fracture mechanism for both as-sintered and optimal aged Nd Fe B magnets. Aging treatment changes the morphology and distribution of the Nd-rich phases, reducing the sliding resistance between Nd_2Fe_(14)B main crystal grains and lowers the grain boundary strength, which is the main reason for the strength and fracture toughness decrease of the aged Nd-Fe-B magnets.     

小麦硬度测定方法

本文收集了国内外二十篇不同时期有关硬度研究的文献和资料,扼要权述了研究小麦硬度测定方法的意义和各种方法的原理、依据及影响因素,最后作了综合评价。     

维氏硬度计数字化原理

用力传感器和位移传感器实时自动测量试验过程中试验力和压头压入试样的深度并显示 ,以控制试验进程 ,保证试验的有效性 ;卸除试验力后 ,由位移传感器在线自动测量残余压痕深度 ,自动计算、输出维氏硬度值 ,保证试验结果获取的实时性 .这是维氏硬度计数字化最简洁、有效的方法 ,使维氏硬度试验能方便地用于硬度的常规检验 ,解决了实际应用中以维氏硬度作为统一的硬度标度的技术问题     

丙烯净化器“飞温”事故后的检测与安全分析

为了判断发生“飞温”事故后的丙烯净化器能否继续安全使用,进行了系列检验,采用具有早期缺陷诊断功能的金属磁记忆技术,并应用强度理论对容器进行了安全评价:由于在役容器无法实行力学性能的直接检测,分别进行了硬度、金相、超声探伤及1．28倍的水压试验,同时进行应力测试及金属磁记忆跟踪检测发现,过烧部位晶粒变大、珠光体组织有明显聚集;硬度值比正常母材区降低近30％;磁记忆信号随工作应力增加出现异常．为监督其变化趋势,于容器运行一个月后的卸压状况下进行了第2次跟踪检测．结果表明,容器过烧后强度储备下降,在正常工作压力2．5 MPa下,Tresca应力安全系数约为1．9;过烧区存在多处应力集中,运行一个月后应力集中程度略有增加．     

Surface performance of workpieces processed by electrical discharge machining in gas

The surface performance of workpieces processed by electrical discharge machining in gas(dry EDM)was studied in this paper.Firstly,the composition,micro hardness and recast layer of electrical discharge machined(EDMed)surface of 45 carbon steels in air were investigated through different test analysis methods.The results show that the workpiece surface EDMed in air contains a certain quantity of oxide,and oxidation occurs on the workpiece surface.Compared with the surface of workpieces processed in kerosene,fewer cracks exist on the dry EDMed workpiece surface,and the surface recast layer is thinner than that obtained by conventional EDM.The micro hardness of workpieces machined by dry EDM method is lower than that machined in kerosene,and higher than that of the matrix.In addition,experiments were conducted on the surface wear resistance of workpieces processed in air and kerosene using copper electrode and titanium alloy electrode.The results indicate that the surface wear resistance of workpieces processed in air can be improved,and it is related with tool material and dielectric.     

Microstructure and properties of nitrided layer of titanium plate,produced by simultaneous laser quenching and liquid-nitrogen cryogenics

In the present study, titanium plate was treated by a novel method of laser quenching, simultaneously combined with liquidnitrogen cryogenics(LQLNC). The microstructure and properties of the titanium plate after treatment were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, Vickers hardness testing, and friction wear testing.The results show that the treated titanium plate is covered by a nitrided layer with a homogeneous thickness of about 60 μm,while the nitrided layer consists of Ti N and α-Ti phases. Compared to general laser quenching, the LQLNC treatment increases the hardness and wear resistance of the surface-modified layer of the titanium plate. As a result of grain refinement in the nitrided layer, the cracking induced by the rapid solidification of the conventional laser-quenching process has also been effectively solved.     

风电塔筒基础环的金属监督检验

介绍了风电塔筒基础环的金属监督检验模式,分析了其技术特点,将此检验模式应用于某风电场塔筒基础环的金属监督工作。结果表明,以目视检测、磁粉检测、超声检测、金相检验与硬度测试为主的检验模式比较完善,能够较为全面的对基础环的缺陷状况进行评估,具有推广价值,对开展其他风机设备的金属监督检验工作具有积极的参考和借鉴作用。     

热处理对TRIP590钢微观组织及力学性能的影响

采用Gleeble3800热模拟机对TRIP钢拉伸试样进行不同工艺条件的快速热处理模拟实验,并采用金相分析、显微硬度测试等方法对试样进行组织观察和性能测试,目的是通过适宜的热处理工艺促使材料微观组织中出现适量的残余奥氏体组织,增强该材料在变形过程的相变诱导塑性（TRIP）效应,强化材料.结果表明：在两相区内,TRIP钢中的残余奥氏体含量随着退火温度和退火时间的增加而增大,以25℃/s缓慢加热到700℃,再以150℃/s的速率快速加热到820℃保温120 s后淬火处理,处理后的试样,残余奥氏体体积分数达到13%,显微硬度最高,达到262 HV.     

Metal magnetic memory testing for early damage assessment in ferromagnetic materials

In order to investigate the physical mechanism of metal magnetic memory testing, both the influences of earth magnetic field and applied stress on magnetic domain structure were discussed. Static tension and fatigue tests for low carbon steel plate specimens were carried out on hydraulic servo testing machine of MTS810 type and magnetic signals were measured during the processes by the type of EMS-2003 instrument. The results indicate that the initial magnetic signals of specimens are different before loading. The magnetic signals curves are transformed from initial random to regular pattern due to the effect of two types of loads. However, the shape and distribution of magnetic signal curves in the elastic region are different from that of plastic region in tension test. While in fatigue test those magnetic signals curves corresponding to different cycles are similar. The Hp (y) value of magnetic signals on the fracture zone increases dramatically at the breaking transient time and positive-negative magnetic poles occur on the two parts of fracture zone.