铝锆炭滑板的热化学侵蚀机理

分析了宝钢３００ｔ钢包滑板使用后的损毁情况。研究了滑板的氧化,铁、锰的氧化物及钙对滑板的化学侵蚀,提出了铝锆炭滑板的热化学侵蚀机理,并指出了滑板的发展方向。     

连铸用滑板的发展概况及其损毁机理

着重介绍了连铸用滑板的发展概况以及滑板的分类,概括了各类滑板的制备工艺及其使用过程中的优缺点。在滑板的使用过程中,其损毁主要原因是热机械损毁和热化学损毁,并根据滑板损毁的主要原因简单介绍了防止滑板损毁的主要措施。     

钢包滑动水口存在的问题及解决方法

由于唐山钢铁公司一炼钢厂原用滑动水口系统存在一定缺陷,导致滑动机构使用的可靠性不强,且浇钢用滑板砖仅使用一次。这不但增加了工人的劳动强度及周转钢包数量,而且不利于钢包温度的提高,同时也造成浇钢系统耐火材料消耗较高。鉴于此,通过采取改进钢包滑动机构,调整滑板孔径和提高滑板质量等措施,解决了滑板面使用一次后即出现拉钢的现象以及时常出现的滑板刺钢事故,实现了钢包滑板连用。1滑动水口系统存在的问题1.1滑板孔径一炼钢供小方坯用钢包滑板直径50mm,因直径较大,在浇钢过程中需多次开关滑板。使用后的滑板侵蚀较严重,滑板面间…     

天铁180t钢包滑板的多炉连用技术

分析了影响天铁热轧板有限公司钢包滑板多炉连用的因素,介绍了为提高钢包滑板多炉连用技术所采取的措施以及滑板多炉连用技术在天铁热轧板有限公司的实际使用效果。     

钢包用碱性滑板的开发

为了提高钢包用滑板在高侵蚀性钢种中的寿命，以连铸滑板所用镁碳材料为基础，其部分氧化镁骨料换成氧化铝，制成碱性材料，并应用于实验室及实际工程中。得出的结论是：Ca处理钢中，碱性材料比铝碳的损毁速度降低了两成，高氧钢中，碱性材料的损毁速度比铝碳降低了1／4左右。     

金属Al-Si结合Al2O3-C滑板的性能和使用

自主研制开发了节能型低碳金属Al-Si结合Al2O3-C滑板,其工艺特点是低温烧成,产品特性是低碳,与常用的Al2O3-C和Al2O3-ZrO2-C滑板相比,具有较高的热态强度,较好的抗热震性和抗氧化性。经大中型钢包的批量使用表明,其连续使用次数是高温烧成Al2O3-C滑板的两倍,与Al2O3-ZrO2-C滑板相当,用后滑板扩孔均匀,拉毛较少,裂纹微细。经残砖分析,认为金属Al-Si结合Al2O3-C滑板使用时的损毁过程可能是:表面工作层的非氧化物首先被氧化,导致结构疏松,强度降低,在铸孔处由高温钢水冲刷引起铸孔扩大,在滑动面处因机械摩擦造成滑动面拉毛。     

新型滑板及其机构在首钢90 t钢包上的应用

通过分析首钢501滑板及其机构存在的问题以及滑板纵向裂纹产生的原因,开发了新型滑板及其配套机构。通过在首钢90t钢包上的使用,证明该滑板的使用寿命有大幅度提高,从而降低了吨钢成本,取得了明显的经济效益和社会效益。     

可重复使用的滑板

为了提高滑板的可靠性和使用寿命,一般采用价格昂贵的高纯原料生产滑板。但是,用后滑板的损毁仅发生在孔周围的小片区域内。为了减少工业废料,降低耐火材料使用成本,日本研究人员研制了一种可循环使用的ECO滑板。设计的ECO滑板的结构示意图见图1。它包括滑板主体     

钢包包底内衬结构的改善

1前言 在实际使用的钢包中，包底衬砖的特定地方发生剥落损毁，加快了损毁速度。因此，采用有限元素法进行了结构分析，研究了旨在抑制钢包包底衬砖断裂的内衬结构。     

中间包用长寿命铝锆炭滑板的研制与使用

为了提高钢水和连铸坯的质量 ,2 0 0 1年 ,本钢二炼钢中间包浇钢由原来的手动控制改为计算机自动控制 ,同时要求中间包滑板提高使用寿命以实现中间包的长寿命化。我厂原来生产的普通型铝锆炭中间包滑板已经不能满足使用要求 ,因此 ,开发了长寿命的铝锆炭中间包滑板。1　中间包用铝锆炭滑板的损毁本钢的中间包已经实现了浇铸自动化 ,通过计算机自动控制中滑板铸孔的开启度 ,以确保结晶器中钢水液面高度的波动在 3～ 5mm内。使用过程中 ,中滑板始终处于工作状态。下滑板铸孔设计为滞流型 ,虽有利于钢水流态的控制 ,却加剧了中、下滑板的损毁。…     

Maerz窑两种常见热工故障的处理

窑膛A出料轻烧白云石的CO2量波动较大，发现18号和20号枪对应的喷枪隔热盖板温度超高150℃以上，该盖板对应的喷枪已经烧坏，喷枪护罩烧坏的可能性非常大。为了确定烧坏程度，停窑打开喷枪盖板进行检查，发现2#和3#喷枪烧断，对应的护罩严重烧坏，针对此问题进行研究并给出了比较安全可靠的解决方法。     

Impact resistance and damage tolerance of scarf‐repaired composite structures: An experimental investigation

The development and application of damage tolerance analysis of aircraft repair structures needs to keep pace with the growing of aircraft structural aging phenomena. The low‐velocity impact performance of scarf‐repaired structures is investigated experimentally in this article. The scarf‐repaired plates and the virgin plates were impacted using drop‐weight test machine at different impact energies. The time histories of impact force were recorded, and ultrasonic C‐scan technology was used to inspect the internal damage of the specimens. Permanent indentation, damage size, dissipated energy and the compression strength (strain) of these plates after impact are discussed contrastively. The results show that the impact resistance and compression behavior performances of prepreg scarf‐repaired plates are better than the virgin plates, while the performances of wet layup scarf repaired are the worst. POLYM. COMPOS., 37:1681–1694, 2016. © 2014 Society of Plastics Engineers     

Behavior of sandwich structures and spaced plates subjected to high‐velocity impacts

This work evaluates the behavior of sandwich and spaced plates subjected to high‐velocity impacts. The sandwich structures were made of glass/polyester face‐sheet and a PVC foam core. The spaced plates were made of two plates of the same material of the sandwich face‐sheet at a distance equal to the core thickness. The residual velocity, the ballistic limit, and the damage area were selected to compare the response of both structures. The residual velocity and ballistic limit was very similar in both cases. Nevertheless, the damage area of sandwich structures and spaced plates differed due to the dissimilar properties between the sandwich core and the air inside of the spaced plates. An analytical model, based on energy criteria, was applied to estimate the residual velocity of the projectile, the absorbed energy by each face‐sheet, and the ballistic limit in the spaced plates. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Influence of external heat flux and coating thickness on the thermal insulation properties of two different intumescent coatings using cone calorimeter and numerical analysis

Polymeric intumescent coatings are fire protective materials that increase their thermal resistance when exposed to high temperatures to prevent building structures from damage. The idea of the investigation was to develop a simple test method to determine the time dependent thermal conductivity of intumescent coatings. Therefore steel plates were coated with two different intumescent systems. During cone calorimeter tests the temperature at the back side of the coated plates was measured. These results were used to calculate the time dependent thermal resistance of the protective layer with the simulation program IOPT2D for different external heat fluxes and different layer thickness. Copyright © 2003 John Wiley & Sons, Ltd.     

110t钢包滑板及其机构的改进与优化

通过优化滑板材质、调整滑板体积、优化滑板形状、改进钢包滑动机构等措施对原滑板进行了改进,改进后的滑板连滑率达到了100%,使用寿命达到了4次,基本上满足了生产要求。     

Preparation,microstructure, and thermal properties of phenolic cryogel composite plates

Phenolic hydrogel plates were successfully fabricated by a microemulsion‐templated sol gel polymerization method. Then, the phenolic cryogel plates were obtained from the hydrogel plates freeze‐dried by the lyophilizer. Ultimately, the phenolic cryogel plates (PCPs) and fiber glass cloth layers were compounded to be the phenolic cryogel composite plates (PCCPs). The pore morphology, mechanical, and thermal properties of the composites were investigated. The experimental results showed that the aerogels made by freeze‐drying method and disposed by acetic acid and tert butyl alcohol had the best microstructure. In addition, it was discovered that the tensile strength of the plates had equally increased for approximately eight times after compounding with the glass fiber cloth layers and the mechanical properties of the 20 wt% and 25% solid content PCPs achieved the optimal value compared with PCPs of other contents. Moreover, it was found that the cryogels had excellent thermostability, and their thermal conductivity decreased with the reducing of the solid contents, what's more, the joining of cloth layers had the increased the composites’ thermal conductivity to some degree. Finally, considering the requirement of low density, good mechanical, and thermal performance, the 20 wt% solid content PCCP had the best comprehensive performance compared with others. POLYM. COMPOS., 38:2294–2300, 2017. © 2015 Society of Plastics Engineers     

Thermal shock behaviour of mullite–cordierite refractory materials

Abstract

The characterisation of thermal shock damage in cordierite–mullite refractory plates used as substrates in fast firing of porcelain whiteware has been investigated. Two different refractory compositions (termed REFO and CONC), characterised by different silica to alumina ratios, were studied. Thermal shock damage was induced in as received samples by water quenching tests from 1250°C. Thermal and mechanical properties were measured at room temperature by means of standard techniques and then the thermal shock resistance parameter R was calculated. The fracture toughness of selected samples was measured before and after thermal shock by the chevron notched specimen technique. The reliability of this technique for evaluation of small differences in fracture toughness after a given number of thermal shock cycles was investigated. The suitability of K _Ic measurements by the chevron notched specimen technique to characterise the development of thermal shock damage in refractory materials was proved in this investigation.     

Silicon Carbide Ceramic Particulate Reinforced AA2024 Alloy Composite - Part I: Evaluation of Mechanical and Sliding Tribology Performance

In this research work, a master batch (comprising of AA2024 alloy, Silicon Nitride (Si3N4) and Graphite particulates) was reinforced by Silicon-Carbide (SiC) ceramic particulates (0–6 wt.-%; at steps of 2%; i.e. four composites samples viz. ASC-0; ASC-2; ASC-4; ASC-6) with the aim of enhancing mechanical and sliding tribology performance. The semi-automatic stir-casting fabrication process was followed as per standard industrial practice in-order-to fabricate the sample plates of the said alloy composites as per design. Thereafter, the sample specimens were prepared via wire EDM cutting followed by polishing over emery paper; as per ASTM standard dimensions and various physical (density and void content), mechanical (tensile strength, flexural strength, impact strength, hardness etc.), sliding tribology performance (steady state sliding wear; ASTM G-99; Pin-on-Disc tribo-meter), thermal (thermal conductivity, Thermo-Gravimetric Analysis (TGA)); thermo-mechanical (Dynamic Mechanical Analysis (DMA)), fracture-analysis, X-ray diffraction (XRD) etc. characterisation were performed and discussed. In Part-1: Physical, mechanical and sliding tribology performances were discussed. The Taguchi design of experiment technique was employed for designing of experimental runs having input controlling parameters like sliding velocity (0.654–2.616 m/s), sliding distance (784.8–3139.2 m), normal load (5–50 N), reinforcement content (0–6 wt.-%) and environment temperature (20–50 °C). The worn surface morphology studies were performed to understand prevalent wear mechanism using Field Emission Scanning Electron Microscope (FESEM) along with Energy-dispersive X-ray spectroscopy (EDS) that reveals elemental composition and its dispersion on the surface. In Part-2: evaluation of characterizations like thermal, thermo-mechanical, fracture-analysis, X-ray diffraction (XRD) etc. were discussed in correlation with mechanical and sliding wear performance. In Part-3: the entire performance data are analysed using hybrid AHP-TOPSIS technique (an MCDM technique; computationally simple and easy to understand) in-order-to rank the composites formulations.     

Elastomer modified phenolic resin-based composites with reduced scale friction: Influence of calcined petroleum coke on tribological and thermo-mechanical behavior

The present investigation deals with the effect of the concentration of calcined petroleum coke (CPC) on the dry sliding wear characteristics of elastomer modified phenolic resin-based friction composites. Other ingredients common in brake formulations like fiber, filler, and solid lubricant were excluded in the present formulations to understand the exclusive effect of the CPC concentration on the frictional, mechanical, and thermal properties of these composites. The composites were fabricated by hot mixing followed by compression molding, and subsequent post-curing. The coefficient of friction (COF) and the specific wear rate of these composites sliding against a cast-iron disc were measured and analyzed. The change in surface topography of these composites before and after sliding operation was investigated by scanning electron microscopy. An effort was made to correlate the surface morphology of these composites before and after sliding with friction and wear behavior. The investigation reveals that CPC inclusion improved the anti-wear behavior as it formed a uniform transfer layer over the rubbing surfaces. In case of optimum CPC loaded (200 phr) composite, the average COF and thermal conductivity values were found to be 0.15 and 0.61 W/m-K, respectively, as compared to 0.12 and 0.25 W/m-K for the base composite (without any CPC).