BFe30-1-1白铜杆的热型连铸

进行了 4、 8BFe30 1 1白铜杆的热型连铸试验 ,在铸型温度 12 30℃、冷却位置 8mm、拉铸速度30mm/min、压头 30mm时 ,可获得表面光洁的 4白铜杆 ;枝晶间距 30～ 4 0 μm ,横向偏析比为 0 .71 压头为 18mm时 ,获得了表面光洁的 8白铜杆 ;枝晶距 4 5～ 5 5 μm ,横向偏析比为 0 .6 3 其σb 为 338～35 3MPa ,δ10 大于 70 % 分析表明 ,缩小两相区宽度并使之位于铸型出口处是消除热裂纹的关键     

淬-回火温度对高强度钢30NCD16组织和性能的影响

试验了电渣重熔高强度钢30NCD16(％:0．31C、1．41Cr、4.01Ni、0．52Mo)840-930℃淬火、350-625℃回火时的组织和力学性能。结果表明,高强度钢30NCD16最佳热处理工艺为840-870℃淬火+560℃回火,可获得细致均匀的索氏体组织,钢的抗拉强度≥1 200 MPa,冲击功A_KU5≥50 J。     

Selected Italian Projects

Rationalism remains at the sidelines of contemporary architecture in Italy – a latent current rather than a leading force. Andrew Peckham and Lucia Tozzi reveal how this stubborn but rich seam is manifesting itself: in Cino Zucchi's substantial housing scheme on the outskirts of Milan; Werner Tscholl's insertion into Schloss Sigmundskron/Castel Firmiano; Beniamino Servino's continued work on the Nursery School in Formicola, Caserta; and C+S Associati's Nursery School at Covolo di Pederobba in Treviso. Copyright © 2007 John Wiley & Sons, Ltd.     

SHS 技术研究进展——纪念SHS 技术诞生三十周年

介绍了自蔓延高温合成技术的发展和国内外研究的概况, 分析了SHS 技术研究与发展的几个重要方向,介绍了SHS 研究的最新动向, 对中国学者在此领域的工作所取得的成果给予了介绍和评价。      

30CrMnSiA合金前端吊耳断裂原因分析

某30CrMnSiA合金前端吊耳发生断裂,对断裂吊耳进行断裂特征分析和硬度测试。结果表明,吊耳断裂性质为氢脆断裂,且存在硬度超标现象。结合吊耳热处理和表面处理工艺对氢脆断裂原因进行分析,表面处理过程中除氢不彻底是造成氢脆的主要原因,而硬度超标不仅增加氢脆敏感性,且误导除氢工艺;同时该失效件反映了供应商质量控制上的不足,需在特殊过程及二次外包上加强控制和审核力度。     

分布式能源用SGT-700工业型燃气轮机与 LM2500 +G4航改型燃气轮机对比分析

为推进分布式能源项目用30 MW等级燃气轮机选型工作,以Siemens公司典型工业型燃气轮机SGT-700和GE公司典型航改型燃气轮机LM2500+G4为研究对象,从结构特点、热力性能、污染物排放特性、燃料适应性、启动及运行特性、供热(冷)能力、检修维护等方面综合对比分析分布式能源用SGT-700工业型燃气轮机与LM2500+G4航改型燃气轮机的优缺点,为30 MW等级分布式能源用燃气轮机主机选型提供参考依据。LM2500+G4燃气轮机对于分布式供能方面具有一定的优势,SGT-700燃气轮机在检修维护上具有一定的优势。     

Effect of particle size on dry sliding wear behaviour of sillimanite reinforced aluminium matrix composites

Present work describes the development of Al-Si/sillimanite reinforced composites via stir casting route. Sillimanite is abundant mineral available in coastal regions of India and has not been explored much as reinforced mineral for the development of composites. In the present work, dry sliding wear behaviour of LM30 aluminium alloy reinforced with sillimanite has been investigated. Composites reinforced with sillimanite in different weight percentage (3–18 wt percentage) and particle size range (fine: 1–20 µm, medium: 32–50 µm, and coarse: 75–106 µm) were prepared. Microstructural studies revealed uniform distribution of sillimanite particles in the matrix of composites. Nanoindentation taken at different phases indicated good bonding between reinforced particles and matrix. Fine particles (1–20 µm) reinforced composites containing 15 wt% sillimanite exhibited higher wear resistance which is 55% more compared to base LM30 alloy. Beyond this reinforcement level, wear resistance deteriorated because of agglomeration of the fine particles. Analysis of wear track and debris revealed that at low applied loads, abrasive wear was predominant whereas at higher applied loads, adhesive wear was dominating factor.     

ICT Diffusion,Foreign Direct Investment and Inclusive Growth in Sub-Saharan Africa

This study examines the joint effects of ICT diffusion (composed of access, usage and skills), and foreign direct investment (FDI) on inclusive growth in sub-Saharan Africa (SSA). The study draws on data from the World Bank’s World Development Indicators, and the Global Consumption and Income Project for the period 1980–2019 for the analysis. The study provides evidence robust to several specifications from the ordinary least squares and dynamic system GMM estimation techniques to show that: (1) unconditionally, both FDI and ICT diffusion induce inclusive growth in SSA; (2) compared to its direct effect, ICT diffusion is remarkable in fostering shared growth in SSA in the presence of FDI, and (3) relative to ICT access and ICT usage, ICT skills is more effective for enhancing inclusive growth in SSA. Overall, FDI modulates our ICT dynamics to engender positive synergy effects on inclusive growth. Policy recommendations are provided in line with the implementation of the African Continental Free Trade Area (AfCFTA) Agreement and the projected rise in FDI to SSA from 2022.     

Mg处理对30CrNi2MoVA钢夹杂物的影响

为了研究Mg处理对钢中夹杂物的影响，采用NiMg合金对铝脱氧30CrNi2MoVA钢进行处理。共进行了3组试验，终点钢中Mg的质量分数分别小于0.001%、0.010%、0.014%。试验结果表明：Mg处理可以起到良好的脱氧、脱硫、脱磷效果，能有效地使钢中夹杂物弥散细小化，同时改变夹杂物的种类和成分。随着Mg含量逐渐增加，钢中夹杂物的平均等效直径由[?2.0×10－6 m]降低至[?1.0×10－6 m，]钢中等效直径小于[?1.5×10－6 m]的夹杂物比例从84.04%提高到93.65%。但当Mg质量分数增加到0.014%时，钢中开始出现少量的大尺寸夹杂物。将试验结果结合热力学计算分析可知，随着钢中Mg含量的逐渐提高，钢中夹杂物种类由Al2O3依次向Al-Mg-O系、MgO和Mg-O-S系转变。当钢中Mg含量进一步增加时，钢中出现细小的单纯MgS和Mg-O-S-P系夹杂物。