Correlations between processing parameters and microstructure for YSZ films produced by plasma spray technique

Yttria-stabilized zirconia (YSZ) powders have been used to prepare plasma-sprayed zirconia films on various substrates employing non-equilibrium plasma spraying technology at atmospheric pressure. The properties of obtained YSZ films 20–60 μm in thickness are presented. This paper shows how the spray regime affects the microstructure of obtained YSZ films by using different shapes of plasma torch-Laval-like contour and cylinder. The influence of process parameters on formation and morphology of as-sprayed films has been investigated using the data of microstructural analysis. The results indicate plasma torch shape and started powder characteristics to be the most important parameters influencing the film microstructure.     

竖冷炉内烧结矿运动行为的离散元模拟

利用离散单元法研究烧结矿竖冷炉在排料过程中颗粒运动的流型和速度分布.模拟结果表明,烧结矿颗粒在下移过程中,运动流型依次呈"一"→"S"→"V"转变;在竖冷炉腔内的大部分区域,烧结矿颗粒保持整体流动;在中心风帽上方的局部区域(宽480 mm,高1280 mm),运动流型会随排料的进行在整体流和漏斗流之间转变.烧结矿颗粒速...     

薄板坯连铸连轧流程专利分析

以Orbit专利分析平台为主要研究工具，从专利文献中抽取专利数量指标和专利质量指标来构建评价薄板坯连铸连轧技术竞争力和企业创新能力的指标体系，结合其他文献研究的成果，从产业发展的实际出发做出分析，系统揭示了自薄板坯连铸连轧技术开发以来的技术进步、专利布局、发展演化、国内外发展现状、技术竞争实力等，有助于在专利文献提供的线索启发下开发新产品、新技术，从而有效提高研发效率。     

材料成分对热镀锌钢板性能及表面质量的影响

针对以往热镀锌板以碳作为强化元素的碳锰设计中易出现成品带钢板面不良的缺陷,以及采用超低碳钢添加微合金元素强化时成本较高的问题,以厚度规格为0.3 mm、强度为320 MPa的典型薄带热镀锌产品为研究对象,研究了成分对成品热镀锌钢板质量的影响;并在成本控制的前提下,通过碳与磷成分的组合优化,提出了一套以碳锰设计为基础、兼顾产品质量的成分综合优化方案。将综合优化方案应用到某钢铁企业的生产实践后,生产出了强度为320 MPa以上、表面无色差等缺陷的镀锌薄板产品,满足了家电裸用的要求,且给企业创造了较大的经济效益,具有进一步推广应用的价值。     

滚筒法不锈钢钢渣处理技术的研究和应用

不锈钢钢渣的环保化处理是钢铁行业面临的难题之一,不锈钢钢渣中高含量游离CaO与MgO导致浸泡处理时粉化严重,环境污染大;不锈钢钢渣中不稳定的六价铬易溶于水造成水体污染。通过对滚筒法处理不锈钢钢渣的工艺抑制不锈钢钢渣粉化和抑制Cr3+的氧化析出进行研究和机理分析,并结合工程实例应用,论证了采用滚筒法处理不锈钢钢渣的可行性,为不锈钢钢渣环保化处理和资源利用奠定了基础。     

IMS多功能测厚仪高压控制发生器故障分析及改进措施

针对宝钢湛江钢铁热轧厂IMS多功能测厚仪高压控制发生器灯丝电流多次异常持续升高的故障情况,检测灯丝电流控制板及灯丝高压变压器部分,对高压控制发生器内部工作情况进行解体检查。得知灯丝高压变压器部分磁芯松动是引起高压控制发生器灯丝电流故障的根本原因,提出防止磁芯发生松动等对策措施,取得了良好的效果,对于同类测厚仪的问题处理及高压控制发生器的控制机理分析具有参考意义。     

热镀锌机组碳化钨喷涂工艺辊表面涂层失效分析

本文主要研究了热镀锌机组喷涂碳化钨的工艺辊在使用过程中发生表面喷涂层发生剥落的原因。 工艺辊基 体材质为 45 号钢, 表面采用超音速喷涂碳化钨涂层, 该工艺辊服役不到一年时间, 发现辊面中部喷涂层剥落。 针对辊面喷涂层剥落问题, 进行了喷涂材料的成分分析、 涂层的微观分析等。 研究发现喷涂前的喷砂工艺非常关 键, 在喷涂层剥落之处可以发现残留的砂粒。 通过涂层断面分析, 进一步的证明了在喷涂前的喷砂毛化工序中, 没有完全清除残留的砂粒会导致在使用过程中喷涂层的剥落。     

Scratch behavior of high speed steels for hot rolls

The scratch behaviors of two high speed steels (HSS) for hot rolls were studied by a Micro-combi Tester, and the emphasis was placed on researching the relations between the microstructure and the scratch resistance property of different HSS. The experimental results indicate that during the scratch process, the carbides are embedded into the matrix, the penetration depth of different HSS is closely related with the matrix hardness, i.e., the higher the matrix hardness, the better the scratch resistance property; and in the matrix, the fine, dispersive carbides are beneficial to form steady friction between the indenter and the scratched materials, but the coarser carbides are easier to fall into pieces.     

Properties of silica sol bonded corundum‐spinel castables for steel ladles

In order to overcome the shortcoming of the calcium aluminate cement (CAC) bonded castables, we prepared corundum‐spinel castables using silica sol as binder and tabular corundum, sintered magnesia‐alumina spinel, and reactive alumina as raw materials in this study. The effect of spinel grain size and solid content of silica sol on the flow value, sintering, mechanical strength and microstructure of the specimens treated at varying temperature of 400, 1000, 1500, and 1650°C for 5 hours in an air atmosphere were studied by SEM and EDS analyses. The results indicate that silica sol is suitable as a binder for corundum‐spinel systems. And silica sol with solid content of 25% bonded samples containing ≤90 μm spinel perform quite better than the others. At the same time, silica sol bonded samples had high strength in medium temperature. This is because that the closer proximity of silica sol and alumina powder and the high activity of nanometer SiO₂ in silica sol are beneficial for the reaction of SiO₂ and Al₂O₃ to generate mullite needed for reinforcement of castables matrix.     

Investigation of the Hot Plasticity of Duplex Stainless Steel

Hot plasticity of a nitrogen alloyed 25Cr 7Ni-4Mo duplex stainless steel was investigated. The results indicate that the main factors affecting the hot plasticity of duplex stainless steel are listed as follows： coalescent force of phase interface, microstructure, and the phase ratio and difference between the mechanical properties of ferrite and austenite. The heat treatment and sulphur contents have a notable effect on the hot plasticity. The reasonable heat treatments and the increased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.