大型铸钢件冒口覆盖剂的性能分析

在综合硅酸盐相图理论知识及大量国内外研究资料的基础上,着重研究SiO2、Fe2O3 对保温冒口覆盖剂的导热系数、熔化温度的影响,以及膨胀石墨对冒口覆盖剂膨胀性和保温性能的影响,并利用扫描电镜分析了冒口覆盖剂高温烧结微观组织形貌及其保温机理.经综合比较分析,优选出一种适合大型铸钢件的保温冒口覆盖剂.     

GL-Ⅰ型冒口覆盖剂及应用

介绍了GL—Ⅰ型冒口覆盖剂的配方及化学组成和在大型铸钢件上使用情况，该覆盖剂能有效地提高铸钢件工艺出品率。     

提高铸钢件冒口补缩率的体会

用水玻璃砂型生产的铸钢件 ,由于水玻璃砂的蓄热系数大于粘土砂的蓄热系数 ,使得冒口的集中缩孔呈窄长形而不是抛物线形 ,且底面尖角易深入到铸件中。为了保证冒口的缩孔全部在冒口中 ,水玻璃砂型冒口就必须适当增加其高度 ,这样就造成铸件收得率和冒口补缩率的下降。实验证明 ,使用保温冒口套和覆盖剂可有效地减少热散失 ,提高冒口的补缩能力。下面着重介绍我厂采用漂珠保温冒口材料及 NZ- F型覆盖剂在铸钢件生产中的使用效果。1　漂珠保温冒口材料及 NZ- F型覆盖剂的配比1.1　漂珠保温冒口材料“漂珠”是火力发电厂排放的灰渣经提选得…     

基于体收缩原则的铸造模具镶块保温冒口设计研究

根据体收缩原则,研究了适用于模具镶块铸钢件加发热覆盖剂保温的冒口设计工艺。研究得出了发热覆盖剂加入量与保温冒口直径的关系,保温冒口的等效模数,以及根据铸件质量选择冒口直径的图表。实践证明,应用体收缩法设计模具钢镶块铸件的冒口工艺简单、实用,有效地提高了生产效率。保温冒口和发热覆盖剂的应用显著提高了模具镶块铸钢件的工艺出品率和冒口的补缩效率,综合经济效益显著。     

铸钢冒口覆盖剂原材料的选择和单因子实验研究

在分析国内外铸钢件冒口覆盖剂的组成、原理、性能等因素的基础上,结合渣系、覆盖剂的组成成分及其他各种因素的影响,并通过模拟实验探讨铸钢冒口覆盖剂发热和保温效果,从而为其成分优化提供理论依据.     

铸钢车轮的铸造工艺设计与生产

对车轮铸钢件的结构及铸造工艺性进行综合分析,针对其壁厚不均匀,易产生缩孔缩松、其砂芯阻碍收缩产生铸造应力易产生裂纹的现象,通过采用浇道通保温冒口及加覆盖剂、制作炮弹形砂芯、倾斜浇注加强补缩等工艺措施,有效地防止了裂纹和缩松的产生,生产出了合格铸件,为类似铸件的生产积累了经验.     

出口铸钢件支座的工艺设计及铸造生产

对质量要求高、出口铸钢件140T支座的结构及铸造工艺性进行了分析,针对铸件厚大热节处易出现缩松、非加工表面粗糙度及尺寸精度要求高的特点,提出了采用浇口通过保温冒口、加冒口补贴及保温覆盖剂强化补缩、倾斜浇注等工艺措施,设计了具体工艺参数,实践表明,有效地防止了裂纹和缩松的产生,生产出了合格铸件.     

铸钢件定轮的铸造工艺改进

铸钢件定轮重１２００ｋｇ，在工厂现有熔化能力（１５ｔ无芯工频感应电炉可正常熔化钢液１６００～１８００ｋｇ）的条件下进行铸造。为此，仅在定轮的轮毂处设置一个保温冒口，浇注时，当钢液液面升至冒口高度的２／３处时，加入保温覆盖剂，使工艺出品率达到７５％，并铸造出组织致密的定轮铸件。     

新型铸钢冒口保温覆盖剂的研制与应用

在分析铸钢冒口覆盖剂基本要求的基础上，设计了铸钢冒口覆盖剂的组成，着重研究了覆盖剂中发热材料、保温材料与触发剂对覆盖剂的发热和保温性能的影响，从而优化出一种新型铸钢冒口覆盖剂。结果表明：该覆盖剂具有发热和保温的双重作用，能明显延长冒口中钢液的凝固时间，提高冒口的补缩能力。     

铸钢件保温补贴与保温冒口的计算机辅助设计

探讨了保温补贴尺寸的设计计算方法，选择了与保温补贴配合使用的保温冒口的尺寸，并编制了计算机辅助设计（ＣＡＤ）程度。生产验证表明，该程序可使铸钢件保温补贴和保温冒口的设计快速准确，操作方便，实用可靠，能使铸钢件的工艺出品率由４５～５５％提高到７０～８５％，具有的应用前景。     

Effect of frequency and thermal aging on various parameters of a dielectric

This paper deals with the experimental analysis to see the effect of frequency and thermal aging on the various parameters such as capacitance and loss factor to see the behavior of a dielectric material (synthetic insulation paper) used in various electrical machines. Firstly the studies were conducted on a fresh sample and then the samples were aged at three different times and temperatures. The various parameters for the fresh as well as aged samples were determined experimentally. The studies showed that with the increase in frequency the capacitance and loss factor of the sample decreases, however with aging (increasing time and decreasing temperature) the values of capacitance and loss factor increases at a particular frequency.     

Effect of accelerated aging on the tensile index of a synthetic insulation paper

This paper explores the possibility of using tensile index as one of the appropriate end point parameters to determine the thermal index of a synthetic insulation paper. The paper samples were aged at three different times and temperatures. The tensile index of fresh as well as aged samples was determined experimentally. The study showed that tensile index could be considered as an appropriate parameter to find the thermal index of the chosen synthetic insulation paper.     

Study of dispersion, absorption and permittivity of an synthetic insulation paper—with change in frequency and thermal aging

This paper deals with the calculation of various parameters such as dispersion, absorption and permittivity of synthetic insulation paper to see the effect of frequency and thermal aging to be used in various industrial applications. Firstly the calculations were made for a fresh sample and then for the samples, which were aged at three different times and temperatures. These calculations were done using the earlier reported data [1] of capacitance and loss factor. The studies showed that with the increase in frequency the dispersion, absorption and permittivity of the samples decrease, however, with aging (increasing time and decreasing temperature) the values of dispersion, absorption and permittivity increase at any fixed frequency.     

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介绍了导热系数的传统测量方法—热线法,在此基础上设计了导热系数在线测量系统。通过与传统的导热系数测量方法比较,该测量系统简化了操作,可在短时间内获得精确的测量结果,设计具有可操作性。     

铸钢冒口覆盖剂保温原理探讨及应用

着重探讨了铸钢冒口覆盖剂的作用机理,提出了冒口覆盖剂的设计原理,推荐了其基本原材料和工艺配方     

炼油设备保温层下腐蚀与防治

炼油工艺设备常会发生保温层下腐蚀，从正确选用保温材料，保温层下腐蚀检测，设备轮廓结构设计，防腐蚀涂层等几个方面讨论了防治措施。     

埋地保温管道的腐蚀调查

对庆哈输油管埋地聚乙烯夹克管保温管道的腐蚀进行了调查和分析,表明存在泡沫水、微生物、杂散电流等腐蚀原因,聚乙烯夹克保护层的屏蔽、IR降对阴极保护有影响。     

Variation of dielectric strength of a insulation paper with thermal aging

As thermal treatment leads to the major changes in the properties of the insulating material due to thermal degradation, that is why, in this paper we are studying the effect of thermal aging on dielectric strength of a insulation paper so that it can be selected as one of the appropriate end point parameters to determine the thermal index of a synthetic insulation paper. Aging of the insulating samples was conducted at three different times and temperatures. The dielectric strength of fresh as well as aged samples was determined experimentally. The study showed that dielectric strength could not be considered as an appropriate parameter to find the thermal index of the chosen synthetic insulation paper.     

Effect of pressure holding time of extraction process on thermal conductivity of glassfiber VIPs

Vacuum insulation panels (VIPs) are regarded as the most promising high-performance thermal insulation products on the market today. A high and stable vacuum state within VIP enclosure provides a durable service life for VIP. In this paper, multiple core material layers (CMLs) with thickness of 0.5 mm, 1 mm, 3 mm, and 7 mm were formed as the core of glassfiber VIPs. The microstructure of the core materials and thermal conductivity of as-prepared VIPs was investigated. The porosity of the core materials was about 90% while the mean pore diameter was about 10∼25 μm. At adopted pressure holding time of extraction process of 180 s, the initial total thermal conductivity of VIPs was lower than 4 mW/(m K) and slightly increased with total thickness of core material, but increased greatly with CMLs thickness. Mass transfer characteristics within core material during extraction process was analyzed based on the interlayer-microstructure model. Residual gases within VIPs were mainly extracted from the connected gas flow channel built by glass fibers. The optimum pressure holding time for VIPs with 0.5 mm-thickness, 1 mm-thickness, 3 mm-thickness, and 7 mm-thickness CMLs was 300 s, 240 s, 240 s, and 180 s, respectively.     

面向极寒温度的新型坡口机液压泵站设计

已经建设完成的中俄原油管道二线工程在冬季施工过程中途经黑龙江漠河等东北地区,冬季平均气温低。坡口机液压泵站采用柴油发动机作为动力在低温条件下使用面临着无法启动等问题。针对东北地区-40 ℃低温,设计一种在极寒温度工况下使用的坡口机液压泵站,该液压泵站采用整体式框架结构,发动机采用密闭式保温设计,具有良好的低温防护性能。同时,对液压控制系统进行优化设计,对液压元件进行优化选型,解决了液压泵站在低温环境下的使用问题,确保了工程现场的使用。