Ni9钢焊接热影响区低温韧性的研究

采用焊接热模拟技术、-196℃示波冲击试验、金相显微分析、透射电镜分析技术考察了Ni9钢焊接热影响区粗晶区（CGHAZ）的低温韧性及其与焊接热循环的关系。结果表明，焊接热循环次数以及二次焊接热循环的峰值温度是影响其CGHAZ低温韧性的主要工艺因素；二次热循环在适当的峰值温度作用下促使钢原焊接粗晶区组织分解，并在晶界位置获得部分富Ni回转奥氏体，是原焊接粗晶区低温韧性得以改善和提高的组织成因。     

MODELLING OF P/M FORMING PROCESSES BY FEM

ＭＯＤＥＬＬＩＮＧＯＦＰ／ＭＦＯＲＭＩＮＧＰＲＯＣＥＳＳＥＳＢＹＦＥＭ￥Ｗｅｉ，Ｙｕａｎｐｉｎｇ；Ｒｕａｎ，Ｘｕｅｙｕ（ＤｅｐａｒｔｍｅｎｔｏｆＰｌａｓｔｉｃｉｔｙＴｅｃｈｎｏｌｏｇｙ，ＳｈａｎｇｈａｉＪｉａｏＴｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｓｈａｎｇ...     

基于特征模板的分组编程法

介绍了国内数控加工中存在的问题，结合广东省科委项目，提出了基于平面、曲面特征模板的分组加工编程法，并用实例验证了这种方法的正确性，极大地提高UG软件的加工编程效率，也解决了加工编程难以掌握的问题。     

Effects of secondary carbide precipitation and transformation on abrasion resistance of the 16Cr-1Mo-1Cu white iron

The relationship between secondary carbide precipitation and transformation of the 16Cr-1Mo-1Cu white iron and abrasion resistance were investigated. The results show that secondary carbide precipitation and transformation at holding stage play an important role in the hardness and abrasion resistance. After being held for a certain time at 853 K for subcritical treatment, the grainy secondary carbide, (Fe,Cr)₂₃C₆, precipitated first and then Fe₂MoC or MoC carbides precipitated in the alloy, both of which improve the bulk hardness and abrasion resistance of the alloy. The reasons for these improvements are the secondary carbide precipitates from the austenite and the retained austenite transforms into the martensite, both make the matrix strengthen. So the matrix has more effective support to the harder eutectic carbide against exterior abrasion. With expanding the holding time, the in situ transformation from the granular (Fe,Cr)₂₃C₆ carbide into laminar M₃C carbide causes the formation of the pearlitic matrix and an associated decrease of the alloy abrasion resistance.     

正向充液变薄拉深工艺的研究

提出了一种称为正向充液变薄拉深的工艺方法。从理论上推导出变薄成形传力区拉应力计算式，并采用软铝车削毛坯进行了正向充液变薄拉深试验。当液压达到了１２０ＭＰａ时，车削铝毛坯的极限变薄拉深系数由０．５减小到０．３，说明正向充液变薄拉深工艺能有效地提高一次变薄拉深成形极限。     

Microstructures of mechanically activated Ti-46at.% Al powders and spark plasma sintered ultrafine TiAl alloy

Powder of Ti-46at.%Al was synthesized through mechanical activation (MA) for different milling times, and the 16 h MAed powder was sintered by using a spark plasma sintering (SPS) process at different sintering temperatures. The XRD profiles showed that the MAed Ti-46at%Al powder for 12,16, and 20 h contained initial α-Ti and Al phases, and that the SPSed TiAl alloys contained the gamma TiAl and α2-Ti3Al phases. The TEM showed two different types of regions in the 16 h MAed Ti-46at.%Al powder. One type consisted of only Al with a grain size about 80 nm, and the other type a mixture of Al and Ti with a grain size of 30 nm. According to the optical micrographs of MA-SPSed samples, the alloys sintered at higher temperatures showed a coarser microstructure. In the case of the 1473 K sintering, typical duplex structures ((α2 + γ) lamella and γ phases) with interlamellar spacings of 50-400 nm and the grain size either less man 100 nm, or 1000 nm were observed.     

弯曲回弹逆解公式及其在焊管预弯机组设计中的应用

根据小曲率弯曲成形的特点，考虑了板料弯曲的纯弹性变形部分对回弹的影响，推导出根据板料强度、厚度和最终成形半径直接计算弯曲半径的回弹逆解公式，并应用于大口径UOE焊管预弯成形的设计上。根据计算公式给出了B-X100钢级板料UOE焊管预弯成形的预弯辊半径优化设计诺谟图。     

大规模定制环境下基于产品结构复杂度的工时定额制定研究

针对大规模定制环境下产品种类多、工时制定困难的特点,为了能够快速且准确获取产品工时,研究了产品结构复杂度与工时之间的关系,提出了一种基于产品结构复杂度的工时估算方法.综合考虑影响产品结构复杂度的各种因素后,针对决策结果的排序向量决定决策者权重,引入灰色关联理论,建立了产品结构复杂度计算模型.基于数据库中的工时信息,运用MATLAB软件进行编程确定产品结构复杂度和工时之间的函数关系.最后,以某企业产品加工工时估算实例,证明了所提出的估算方法的可行性.     

事件常识的获取方法研究

在动态语义学的基础上,以事件的语义、文法和常识为标准构建多层次的事件分类体系,并使用该分类体系提取事件的常识知识。事件采用框架的方式来表示,称为事件框架。事件框架的内容包括事件的定义、事件之间的关系、事件的文法表达、事件的谓词表示、事件的例句、事件的前提常识和后果常识。利用事件框架的内容提取事件的常识。为了说明该方法的实用性,以事件分类体系中典型的“交易类”事件为例来描述事件常识的获取方法。