改进智能高温高效节能电炉及耐火材料

为了解决电炉工作时耗能高的问题,对我所自行研制的智能高温电炉做进一步改进.改进后的电炉选用氧化铝纤维耐火材料作为炉材,以二硅化钼作发热元件,选用了以工业PC为核心的电流反馈系统作电气控制.经过有关部门测试,其性能指标高于JB4311.7-91标准.能耗低于普通电炉的50%,工作省时,工作效率高于普通电炉5倍以上,长期工作温度1650℃,最高使用温度为1700℃,耐急冷急热性好,寿命为普通电炉的3倍,正常工作时炉体表面温度低,工作环境好.     

金刚石修整滚轮CAD/CAPP集成技术研究

金刚石修整滚轮是目前最为有效的高效、高精砂轮成形修整工具，迎合了磨削技术高精、高速和高效发展趋势，内电镀高精度修整滚轮制造工艺复杂、工序多，影响制造精度因素较多，修整参数选择、滚轮图纸设计和工艺编制是生产中的关键环节。本文从分析金刚石修整滚轮设计制造的特点人手，应用CAD／CAPP集成技术实现了金刚石修整滚轮设计、工艺规程编制和技术文件管理的自动化，提高了滚轮制造工艺水平和对产品质量的控制能力，较好地解决了一些设计和工艺过程相对简单、变化较小的定型产品的CAD／CAPP集成化的问题。     

EFFECT OF HEAT TREATMENT ON MECHANICAL PROPERTIES OF 0Cr12Mn5Ni4Mo3Al

In this work, the effect of solid soluble temperature, cold treating temperature and ag-ing temperature on the mechanical properties of 0Cr12Mn5Ni4Mo3Al had been inves-tigated systemically. The results show that under the optimal parameters (solid solubletreatment 1050℃×40min, cold treatment -78℃×4h, aging treatment 520℃×2h) theproperties (strength and tenacity) could be up to its maximum.     

Fabrication of WC/Fe composite coating by centrifugal casting plus in-situ synthesis techniques

Using tungsten wires as a reactive source, an iron-based composite coating, reinforced by tungsten carbide (WC) particles, with a thickness of 3.0 mm, was fabricated on the surface of a gray cast iron substrate by centrifugal casting plus in-situ synthesis techniques. With the help of differential thermal analysis (DTA), an appropriate pouring temperature of the gray cast iron molten was determined to be 1300 °C. The experimental results show that the composite coating is dense and consists mainly of primary WC carbides, fine secondly WC carbides as the reinforcing phases and pearlite accompanied by negligible graphite flakes as the matrix. Wear resistance of the composite coating was determined with a pin-on-disc wear test technique, indicating that the composite coating, containing high volume fraction of hard WC carbides, present good wear resistance property compared with the un-reinforced gray cast iron, regardless of load level. Additionally, according to the Fe-W-C ternary phase, reaction paths between tungsten wires and molten, and in-situ synthesis of WC particles, were investigated.     

熔体过热处理对亚共晶Al-10Mg2Si合金磨损性能的影响

对亚共晶Al-10Mg2Si合金进行熔体过热处理,通过削-盘式摩擦磨损试验研究了显微组织对亚共晶Al-10Mg2Si合金磨损性能的影响。结果表明,熔体过热处理后,初生α-Al相转变为近球状等轴晶,Mg2Si相呈纤维状和短杆状均匀分布,且其二次枝晶间距降低了58%,硬度提高了13.5%,同时其磨损速率降低了16.49%。磨屑由合金未经熔体过热处理的推碾薄片状与卷曲状转变为小块粉末状,剥落区面积减小,剥落坑、犁沟和挤压沟槽均变浅。磨损机制由粘着磨损、氧化磨损和磨粒磨损共存转化为以剥层磨损为主,粘着磨损与部分氧化磨损共存的形式,说明熔体过热处理改善了合金的磨损性能。     

42CrMo钢锻件的白点研究

对42CrMo钢锻件白点的生成原因进行研究,采取相应的冶炼、锻造和热处理工艺和方法进行控制,以避免白点生成,提高42CrMo钢锻件质量。     

基于FORGE-3D径向锻造工艺的数值模拟

采用有限元模拟软件FORGE-3D,对径向锻造轴类件工艺参数进行数值模拟研究。分析不同径向压下量、夹头转速和轴向进给速度对锻透性和生产效率的影响。结果表明:锻造过程中,径向压下量越小、夹头转速越高和轴向进给速度越慢,则锻件外表面就越光滑,表面粗糙度越小,尺寸精度越高。径向锻打45钢Φ110 mm棒料的最佳条件为:径向压下量5 mm,转速30 r·min~(-1),轴向进给速度20 mm·s~(-1)。通过模拟仿真来验证和优化径向锻造工艺,大大降低了径向锻造工艺开发的周期,降低了多次锻造实验的成本。     

钢锭铸锻一体化开坯工艺数值模拟

针对13 t的12Cr2Mo1V钢锭开坯后探伤不合格问题,提出了铸锻一体化开坯数值模拟分析方法。首先在THERCAST软件中完成钢锭的浇铸和凝固过程的仿真分析,然后通过数据共享将铸造数据结果导入到锻造分析软件FORGE中,完成最终的开坯仿真分析。分析表明:通过铸锻一体化开坯数值模拟分析方法,有效地预测了锻件疏松出现的部位。钢锭最初的疏松出现在中心部位,其Niyama值较大,随着锻造过程的进行,中心部位的疏松区域逐渐消失,其Niyama值变小。通过调整开坯过程的重要工艺参数,如锻造比、相对送进量、温度控制等,制定合理的开坯工艺来减轻或消除疏松、缩孔影响,使显微空隙及疏松通过锻压焊合。     

第二代先进高强钢TWIP钢在车身典型零件上的应用

开发兼具高强度和优良伸长率的高强度钢板,对车身轻量化和提高汽车安全性具有重要意义。深入解析了HC450/950TW钢微观组织、力学性能、成形特性,并通过有限元仿真分析和冲压试验研究了HC450/950TW减震器支座成形性。结果表明:TWIP钢的成形性能大幅优于同级别的QP钢和DP钢,HC450/950TW伸长率大于50%,n值超过0.48。减震器支座应用HC450/950TW成形后,拉延成形深度达到150 mm,零件无开裂、起皱缺陷,成形性良好,并可实现减重2.4 kg,轻量化效果显著。TWIP钢适用于对拉延和胀性要求很高的车身结构零件。     

Microstructure and Property of Cu/Al Joint Brazed with Al-Si-Ge Filler MetalEI北大核心CSCD

Cu/Al brazing has good prospect for applications in the air conditioning and refrigeration industry. A suitable filler metal is the key of Cu/Al brazing. The chemical and physical properties of the filler metal have great influence on the brazing process and parameters. And the strength of the brazing joint is closely related to the properties of the filler metal and the brazing process. While the previous studies have not developed a kind of Cu/Al brazing filler metal which can achieve a tough joint at a low brazing temperature. In this work, the Al-5.6Si-25.2Ge filler metal was first used to braze Cu/Al dissimilar metals, and the melting characteristics of the filler metal, spreading wettability, Cu interfacial structure and strength of brazed joint were investigated systematically. Additionally, the common Zn-22Al filler metal was also used for comparison. The results show that the Al-5.6Si-25.2Ge filler metal possesses low melting temperature (about 541 degrees C) and excellent spreading wettability on Cu and Al base metals. The interfacial structure of Al-5.6Si-25.2Ge/Cu was CuAl2/CuAl/Cu3Al2. The thickness of planar CuAl and Cu3Al2 phases was only 1 similar to 2 mu m, and the thickness of cellular CuAl2 phase was about 3 mu m. The interfacial structure of Zn-22Al/Cu was CuAl2/CuAl/Cu9Al4, but the average thickness of the CuAl2 layer was up to 15 mm. The test results of the shearing strength show that the shearing strength of the Cu/Al joint brazed with Zn-22Al filler metal was only 42.7 MPa, but the shearing strength brazed with Al-5.6Si-25.2Ge filler metal was higher (53.4 MPa).