H10Cr4Mo4Ni4V钢制轴承外圈热处理工艺

通过对高温渗碳钢 (H10Cr4Mo4Ni4V)制轴承外圈的热处理工艺参数的试验 ,确定了该钢制轴承外圈热处理工艺 ,使其产品质量达到技术要求。附图 6幅     

SG13Cr4Mo4Ni4V轴承钢渗碳及热处理工艺研究

通过对SG13Cr4Mo4Ni4V钢渗碳及热处理工艺的深入研究，简述了各工艺参数的制定原则和在加工过程中渗层及基体的成份、组织、性能的变化情况，同时对该材料在轴承上的应用情况作了部分介绍。     

高温渗碳轴承钢10Cr4Ni4Mo4V的渗碳热处理

10Gr4Ni4Mo4V钢具有良好的渗碳性能,采用930℃恒温、恒碳势阶梯式变化渗碳既可保证渗碳层质量,又能获得较高渗速.中间处理采用750℃×5h高温回火为宜,最终热处理采用油淬后三次高温回火.介绍了不同工艺参数对渗层组织、深度及热处理后硬度的影响.附图7幅,表1个.     

高温8渗碳轴承钢10Cr4Ni4Mo4V的渗碳热处理

10Cr4Ni4Mo4V钢具有良好的渗碳性能 ,采用 930℃恒温、恒碳势阶梯式变化渗碳既可保证渗碳层质量 ,又能获得较高渗速。中间处理采用 750℃× 5h高温回火为宜 ,最终热处理采用油淬后三次高温回火。介绍了不同工艺参数对渗层组织、深度及热处理后硬度的影响。附图 7幅 ,表 1个。     

SG13Cr4Mo4Ni4V钢轴承套圈热处理工艺改进

为解决轴承套圈在密封箱式渗碳炉中渗碳表面浓度不达标和渗碳层不均匀的问题,进行SG13Cr4Mo4Ni4V钢预氧化工艺技术研究,建立预氧化处理与表面渗碳效果的关系,根据尺寸与装载量选择最佳的预氧化时间,改进原热处理工艺规范。结果表明:SG13Cr4Mo4Ni4V钢轴承套圈最佳预氧化处理工艺为(945±5)℃×(30~40)min。经该工艺处理后,套圈达到了技术指标要求,满足了轴承的使用性能。     

轧钢机用G20Cr2Ni4钢制轴承外圈渗碳热处理工艺

针对用G20Cr2Ni4渗碳钢以深层渗碳制造的大型轧钢机用NNCF41104160Y轴承外圈,介绍了其渗碳热处理工艺和淬、回火工艺的制定与控制,渗碳+淬、回火后质量检验表明:各项性能指标均达到标准要求.     

SG13Cr4Mo4Ni4V钢轴承套圈热处理工艺改进北大核心

为解决轴承套圈在密封箱式渗碳炉中渗碳表面浓度不达标和渗碳层不均匀的问题,进行SG13Cr4Mo4Ni4V钢预氧化工艺技术研究,建立预氧化处理与表面渗碳效果的关系,根据尺寸与装载量选择最佳的预氧化时间,改进原热处理工艺规范。结果表明：SG13Cr4Mo4Ni4V钢轴承套圈最佳预氧化处理工艺为（945±5）℃×（30～40）min。经该工艺处理后,套圈达到了技术指标要求,满足了轴承的使用性能。     

H10Cr4Ni4Mo4V钢表面渗碳层硬度对接触疲劳寿命的影响

进行了H10Cr4Ni4Mo4V钢经渗碳热处理后，渗层表面硬度值的大小及均匀性对接触疲劳寿命的影响试验。结果表明，在渗碳表面硬度低或极其不均匀的情况下，其疲劳寿命远远低于渗层表面硬度高且均匀的试样寿命。在渗碳热处理时，渗层表面硬度值应控制在60．0～65．0HRC，且同一零件硬度差不大于2HRC。     

Cr4Mo4V钢热处理工艺对残余奥氏体量的影响

经对Cr4Mo4V钢进行热处理工艺试验，分析工艺参数对残余奥氏体量的影响，优化了热处理工艺参数，使Cr4Mo4V钢残余奥氏体量控制在5％以内，保证了热处理质量及尺寸稳定性。     

小型渗碳轴承材料及其热处理工艺探讨

剖析日本小型渗碳轴承的结果,可以认为其材料为SNCM21低合金渗碳钢,其热处理工艺过程为渗碳→高温回火→淬火→低温回火。附图5幅,表4个。     

Role of PO4 tetrahedron in LiFePO4 and FePO4 system

Using high resolution transmission electron microscopy with image simulation and Fourier analysis, the Li_1?xFePO₄ (x < 0.01), Li_1?x FePO₄ (x ～ 0.5), and FePO₄ particles, prepared by charging or discharging the 053048 electrochemical cells (thickness: 5 mm, width: 30 mm, height: 48 mm) and dismantled inside an Ar‐filled dry box, were investigated. The high resolution images reveal: (1) the solid solution of Li_1?xFePO₄ (x < 0.01) contains some missing Li ions leading PO₄ group distorted around M1 tunnel of the unit cell; (2) the texture of the particles of Li_1?xFePO₄ (x ～0.5) has homogeneously distributed compositional domains of LiFePO₄ and FePO₄ resulting from spinodal decomposition which promote Li ion easily getting into the particle due to uphill diffusion, (3) the particles of FePO₄ formed in charging have heavily distorted lattice and contain some isolated LiFePO₄, (4) interface between LiFePO₄ and FePO₄ and between amorphous and crystal region provides the lattice distortion of small polarons. Microsc. Res. Tech. 78:462–471, 2015. © 2015 Wiley Periodicals, Inc.     

G13Cr4Mo4Ni4V轴承钢球磨削烧伤组织观察

本文通过体式显微镜、光学显微镜、XRD相分析、扫面电子显微镜及EDS能谱分析等技术方法,对高温渗碳轴承钢G13Cn4M04Ni4V渗碳表面磨削过程中产生的轻度烧伤处的组织和性能进行了系统分析。结果表明,烧伤形貌有直线型,有曲线型,亦有圆点状;烧伤处宽度一般在0．2-0．4mm之间,烧伤变质层深度主要集中在2μm以内;酸洗后,烧伤处较未烧伤处表面粗糙度更好;EDS能谱分析表明烧伤变质层中氧元素含量升高;XRD相分析表明烧伤变质层组织为马氏体,略见少量奥氏体。     

NH_4ZnPO_4晶体结构Rietveld法精修

本文详细阐述用X射线粉末衍射及Rietveld法研究NH_4ZnPO_4晶体结构精修的实验方法。通过对85个结构模型参数、样品特性参数和仪器对衍射谱图的影响参数进行精修,进一步说明在精修过程中应注意的问题。该样品为单科晶系,其空间群为:P2_1,Z=4,精修后的晶胞参数为:a=8.7839(13)A,b=5.4432(21)A,c=8.9543(13)A,β=90.318(38)°,v=428.126(14)×10~(-10)m,Dx=2,830g/cm~3,品质因子:F(20)=27,M(20)=39,结构吻合因子:Rp=16.98％,Rwp=21.25％,R_(EXP)=16.18,S=1.3。     

4-4BS型扫描电镜故障分析与处理

本文概述了4-4BS扫描电镜的几例故障分析及排除方法,例如真空系统、扫描电路、电压电源、水冷系统等部分故障。     

Singularity analysis of a novel 4-dof parallel manipulator H4

Recently, it has been shown that a novel parallel manipulator called H4 can be employed to perform high speed motion for semiconductor applications. In this new family of parallel manipulator, singularities are associated with either loss or gain of degrees of freedom (DOF). This paper deals with singularity analysis of H4 utilizing line geometry tools and screw theory. Firstly, the static equilibrium condition of the end effector is derived to obtain the full 6×6 matrix, which is set of governing lines of the manipulator. Based on linear dependency of these lines, the singular configurations of the manipulator can be identified. Moreover, in order to deal with singularities associated with loss of DOFs (serial singularity), the static equilibrium of the actuators is also defined. Secondly, architecture and constraint singularities associated with gain of DOFs (parallel singularity) are defined and analyzed using linear complex approximation algorithm (LCAA), which is employed to obtain the closest linear complex, presented by its screw coordinates, to the set of governing lines. The linear complex axis and pitch provide additional information and a better physical understanding of the manipulator’s self-motion when in or closed to a singular configuration. Lastly, various singularities of an example H4 manipulator are presented and analyzed using the proposed methods.     

CAD_4四圆单晶衍射仪的技术改造

对荷兰ENRAF NONIUS公司的CAD4四圆单晶衍射仪在缺乏核心技术资料的情况下进行了技术改造。剖析了仪器构造,控制机理,保留原有良好的四圆测角仪及高压发生器,彻底更换了主机控制和数据处理软件和硬件,使这台已运行十多年的故障频繁的旧仪器又恢复正常工作。软、硬件的升级改造使之达到了全新水平。