堆焊层中球状碳化物形成机理的研究

通过同时加入球化剂和碳化物形成元素，成功地在堆焊层中形成了球状碳化物，并对这种碳化物的形成过程进行了理论上的探讨。     

含钇奥氏体基堆焊焊条堆焊层研究

针对高温、磨损、热疲劳工况下服役零件的失效，研制了一种含稀土元素钇的奥氏体基沉淀强化型堆焊焊条，并对堆焊层组织与性能进行了较系统的研究。     

支持概念设计的表面蒙面算法

提出一种针对任意多边形边界内嵌任意形状、任意多个内特征的“递归式”三维平面三角划分方法 ,该算法主要应用于产品概念设计中零件的可视化处理。在提出“有效线段”概念及相关三维平面“内外点的判定”方法的基础上 ,提出针对不同内外特征形状的一整套三角划分方法。较之一般的三角剖分算法 ,本方法着重提高了算法的简单性、通用性及处理问题的有效性 ,本文的研究成果已成功应用于“86 3”课题 :基于广义映射原理的绿色产品设计自动化软件系统中     

Policy issues and risk-benefit trade-offs of 'safer surfacing' for children's playgrounds

The case for the universal application of 'safer surfacing' in playgrounds is assessed in terms of absolute risk, cost-benefit, and qualitative factors, and found to be open to question on each front. In parallel, it is noted that members of the child welfare and play communities are increasingly of the view that playgrounds are losing their appeal for children, which in turn has its own health, safety and developmental consequences. In part, this loss of attractiveness may have linkages with the recent concern over play safety and the imposition of measures such as 'safer surfacing'. It is proposed that the drive for play safety, which has existed for some 20 years, should be succeeded by a more holistic approach which, rather than considering play safety in isolation, acknowledges the importance of all attributes of play including child safety both on and off playgrounds, potential beneficial aspects of childhood risk exposure, adventure, and play value.     

E101换热器焊接制造中的几个问题

通过合理选择焊接材料、采取预热、中间消除应力处理和最终焊后热处理等工艺措施,可以有效地防止2．25Cr－1Mo钢的焊接冷裂纹、再热裂纹以及团火脆化．采用“预先堆焊00Cr25Ni13过渡层＋最终堆焊00Cr20Ni10Nb表面层”工艺,可以解决2.25Cr－1Mo钢表面堆焊层的焊接裂纹和剥离问题．     

2.25Cr-1Mo/奥氏体不锈钢堆焊接头熔合区碳的迁移及成分分析

异种钢焊接接头在焊接时或使用期间,发生失效的主要区域通常在熔合区[1],长期以来,异种钢接头熔合区一直是焊接工作者研究的重点.虽然国内外对异种钢接头的熔合区进行了大量的研究[2～4],但仍然有许多问题,尤其是基体为铸造组织的铸钢堆焊奥氏体不锈钢,其基体组织和成分的不均匀性也会对熔合区组织产生不利的影响.对在2.25Cr-1Mo钢上堆焊奥氏体不锈钢的焊接性试验[5]的基础上,重点研究了堆焊接头熔合区碳的迁移及其成分分析,为正确指导大型汽轮机高压模块中分面堆焊及类似产品焊接生产提供了理论依据.图6表3参8     

外加磁场作用下铁基碳弧堆焊层的组织和性能

为了利用磁场的作用提高堆焊层的性能,研究了磁场对铁基碳弧堆焊层组织和性能的影响,在对Cr—B—Ni—V系铁基合全进行碳弧堆焊时加入直流横向磁场,以求细化堆焊层金属的组织,控制硬质相的形态及分布。通过对堆焊层进行硬度试验、磨损试验、金相试验,得出了堆焊电流和磁场电流对堆焊层金属的硬度和耐磨性的影响规律。结果表明：施加磁场的堆焊层比未施加磁场的堆焊层硬度高,耐磨性好;堆焊电流与磁场电流相匹配（堆焊电流180A,磁场电流3A）时,堆焊层的性能达到最佳,即硬度最高,耐磨性最好,此时堆焊层中硬质相细小且分布均匀,呈“六角形”,方向一致。     

SURFACING ELECTRODE WITH CRACKING RESISTANCE AND WEARABILITY

A new surfacing electrode is developed with cracking resistance and wearability based on high microhardness of TiC and VC, carbides of Ti and V are formed in deposited metal by means of high temperature arc metallurgic reaction. The results show the hardness of surfacing metal increases with the increase of ferrotitanium (Fe-Ti), ferrovanadium (Fe-V) and graphite in the coat. However, when graphite reaches the volume fraction of 11%, the hardness reaches its peak value, and when beyond 11%, the hardness falls off. As Fe-Ti, Fe-V and graphite increase, the cracking resistance of deposited metal and usability of electrode declines. Carbides are dispersedly distributed in the matrix structure. The matrix microstructure of deposited metal is lath martensite. Carbides present irregular block. When using the researched surfacing electrode to continue weld with non-preheated, no seeable crack or only a few micro-cracks can be observed in the surface of deposited metal. The hardness is above 60 HRC. The wear res     

对钴基密封面铁含量的研究

介绍了阀门钴基硬质合金堆焊的工艺过程、工艺参数和工艺标准。通过实验研究,得出钴基密封面铁含量的合理范围,并对钴基密封面铁含量在检测过程中出现虚高的情况进行了原因分析。     

Numerical modeling and experimental measurement of MQL impingement over an insert in a milling tool with inner channels

This paper compares experimental and numerical simulations of liquid film formation for different rotating velocities of a milling tool. The numerical model used was based on an unsteady Reynolds–Average Navier–Stokes (RANS) formulation and multiphase Lagrangian model for liquid film formation by the droplet impingement model on a solid surface. The details of spray–wall interaction are presented and the model was used to simulate the liquid film formation in the Micro-Quantity Lubrication (MQL) coolant process for different milling tool velocities. The shape and the size of the liquid film obtained by the calculation and the experiments were compared to improve understanding of the MQL cooling process. Overall, good agreement was observed between the numerical and the experimental measurements of liquid film size from an estimated numerical film thickness border. This study provided greater understanding of oil mist behavior. The impingement analyses predicted better lubrication when highly oriented channels and high inlet pressure were used, especially in High Speed Machining.