304不锈钢圆坯凝固组织优化

为了解决304奥氏体不锈钢连铸圆坯穿管开裂问题,进行了化学成分优化、使用末端电磁搅拌并合理控制过热度试验。试验结果表明:通过优化钢成分,使铸坯心部组织中的δ铁素体面积分数由原来的8.6%降低至7.2%。优化成分后使用末端电磁搅拌使铸坯心部组织中的δ铁素体面积分数降低至5.8%,而且分布比较分散,未使用末端电磁搅拌的铸坯心部δ铁素体呈网状。过热度为30~40℃时对降低钢中δ铁素体含量有利。采取以上措施使304铸坯心部的δ铁素体含量明显降低,穿管开裂现象明显改善。     

炉腹煤气中氢气含量对炉料软熔性能的影响

 在实验室条件下研究了提高炉腹煤气中氢气含量对含铁炉料软熔性能的影响。研究结果表明：随着氢气含量的提高,含铁炉料的软化开始温度先增加后降低,软化终了温度升高,软化区间先变宽后变窄,熔融开始温度、滴落温度升高,熔融区间变窄,炉料透气性明显改善。增加炉腹煤气中氢气含量有利于高炉冶炼。     

基于显微照片的增层模型涂层温度场模拟

熔射成形中涂层的使用性能与其残余热应力密切相关,而残余热应力则是由于沉积过程中温度场分布不均匀导致的,因此,研究涂层温度场是分析其残余热应力的基础。针对现有涂层沉积温度场模拟普遍采用的增层模型不能考虑涂层孔隙的缺陷,提出一种基于显微照片的含孔隙涂层生长增层模型,并使用该模型对其温度场进行模拟。计算结果表明,孔隙不仅对沉积过程中的涂层温度场具有重要影响,而且对基体温度场也有影响。涂层中靠近孔隙的位置其温度下降比远离孔隙位置更慢,且沉积初期这种差异更明显。含孔隙涂层温度场的模拟为含孔隙涂层残余热应力的研究及涂层起翘、开裂和剥落等失效机理的分析提供了基础。     

Porosity and surface roughness simulation of nickel-aluminum coating in plasma spray forming

As the important evaluation parameters concerning the spray qualities, the porosity and surface roughness of the coatings obtained by thermal spray forming have great influence on their forming accuracy, mechanical properties and service lifetime. But it is difficult to predict or control the two parameters for such a highly nonlinear process. A two-dimensional simulation of coating porosity and surface roughness of nickel-aluminum alloy （Ni-5%Al） in plasma spray forming was presented, which was based on the multi-dimensional statistical behaviors of the droplets as well as the simplification and digitization of the typical splat cross sections. Further analysis involving the influence of the droplet diameters and the scanning velocities of the spray gun on the two parameters was conducted. The simulation and analysis results indicate that the porosity and surface roughness are more influenced by the droplet diameters, but less influenced by the spray gun velocities. The results will provide basis for the prediction or control of coating mechanical properties by depositing parameters.     

Plasma spray forming of functionally graded materials mould

A new technology of functionally graded materials(FGM) mould fabricated by plasma spraying and arc spraying was developed. According to applied characteristic of plastic mould, the reasonable coatings of FGM were designed and their microstructures were analyzed. At the same time, some key problems were solved including spray mould fabricating, FGM forming and demoulding, etc. The results show that the service performance of the FGM mould is much more excellent than the one composed of the traditional materials, and the life span can also be greatly increased. The technology will have a significant influence on materials development in mould industry.     

等离子熔射制备梯度功能材料技术

梯度功能材料是一种具有特殊结构和特点的新材料,对该材料的深入研究有助于提升和改造传统的材料产业.应用等离子熔射技术制作了梯度功能材料,对梯度成分进行了设计分析,同时测试了梯度涂层的金相组织以及显微硬度.结果表明梯度功能材料比传统的单一材料以及复层材料使用性能和寿命大大提高.功能梯度材料应用于现代制造业以及对材料表面进行改性将对我国工业技术的发展产生重大影响.     

等离子熔射成形中粉末飞行特性研究

通过对射流图像的采集和处理，研究了气体流量、工作电流对射流温度场分布的影响。根据射流与粉末动量传递和能量耦合关系，建立粉末飞行特性模型，研究不同粉末在射流中的飞行时间，分析粒子飞行的温度特性和速度特性对熔射成形质量的影响。利用双比色原理对粉末飞行模型进行的实验验证表明：模拟结果与实验结果基本吻合，建立的粉末飞行特性模型对单粒子在射流中的飞行特性和动量／能量耦合规律的研究具有重要的意义。     

气固二相流测量用电容传感器分析

分析了三种电容传感器，并对它们的原理，检测方法进行比较，以便使其其更好地应用于生产过程的流量测量和控制，显示和报警等领域。     

转炉托圈机械应力的实验研究与有限元分析

设计制作了转炉托圈实验装置对其在静载荷下采取倾角α为０°,３０°,５５°,９０°四种工况下,分别进行机械应力测量,并进行了有限元计算与分析。实验与分析结果对转炉托圈的设计和使用有一定的指导意义。     

基于LabVIEW的瞬态温度测试系统

针对极端工况下瞬态温度动态诊断的难题,设计了以钨铼快速热电偶为传感元件和LabVIEW为开发平台的测试系统,对热电偶进行了冷端温度补偿,实现了在侵蚀环境下的瞬态温度的诊断.对锌熔滴扁平过程瞬态温度测试表明,其温度变化范围在ms级,并以波形图的形式显示出了瞬态温度的变化情况,对其进行了分析.该系统可用于发动机进口、爆发器内壁等工业和军工中需要快速高温测量的领域.