Effect of Carbon Properties on Melting Behavior of Mold Fluxes for Continuous Casting of Steels

Mold fluxes are synthetic slags used to coverthe liquid steel meniscus during continuous castingof steel.The flux,whichis continuously fed on thesurface of liquid pool during casting,melts first andthenflowsintothe gap between mold wall and solid-ified steel shell.It is well known that the perform-ance of the flux can greatly affect both the castingoperation and product quality.Because of its i mpor-tance,intensiveinvestigations have been performed,and considerable progress has been made[1-6].…     

55t均火炉的温度检测及铸锭均火工艺参数确定

介绍新建的均匀化退火炉的空炉温度和带料温度测试,以及铸锭均火工艺参数的制定方法,并指出确定铸锭均火工艺参数的原则。     

耐候钢异型坯连铸保护渣的工业试验

为控制耐候钢粘结漏钢及其裂纹等质量问题,针对耐候钢异型坯连铸的特殊性专门设计了保护渣,主要从提高原有保护渣的碱度R或F-含量等来实现控热,增强保护渣润滑性能,同时进行了工业性试验。通过优化保护渣性能,漏钢发生率由使用前的约7%减少到〈0.1%,保证了8炉以上连浇,基本解决了耐候钢粘结漏钢问题。     

钢板表面纵向裂纹的金相检验和分析

在连铸轧制的钢板表面有沿轧制方向的裂纹。采用化学成分分析,宏、微观检验等方法对裂纹进行了分析。结果表明,裂纹中存在氧化物及其脱碳等缺陷,这说明连铸坯表面在轧制前已存在裂纹并在轧前加热中裂纹内发生氧化和脱碳,导致轧制后的钢板表面出现裂纹。     

ZG20SiMn铸钢摇臂壳体铸造过程数值仿真及工艺优化

摇臂壳体是采煤机的重要组成部件,具有多级壁厚、变截面等异形特征。为提高采煤机摇臂壳体铸造质量,解决因铸造工艺不成熟导致的缩松、缩孔等缺陷问题。以MG325型采煤机摇臂壳体为研究对象,设计顶注式和底注式两种铸造工艺方案,采用ProCAST软件探究不同浇注工艺方案下摇臂壳体铸件充型及凝固过程,分析铸件温度场、凝固场及缩松、缩孔铸造缺陷位置。基于Niyama判据和应力场分布对底注式铸造工艺方案进行优化。结果表明:优化后摇臂壳体铸件在凝固冷却过程中保持温度梯度递增,促进铸件实现顺序凝固,铸件缺陷率明显降低且充型效果更佳,缩孔体积仅占摇臂壳体体积的0.004 9%,电机孔薄壁端面应力优化量为38.47%,输出端孔处应力优化量达到91.08%。本文研究成果为采煤机摇臂壳体的铸造工艺提供了理论基础和数据支撑。     

过筛煤粉在铸铁件湿型砂铸造生产中的作用

正确选择煤粉,其性能要求同时具有低灰分、高挥发分和高膨胀指数,以及具有合适的筛分粒度这一关键因素,以确保所生产的铸件没有机械粘砂缺陷和表面质量问题.通过仔细选择、安全操作和加工处理,煤粉仍然是一个优良的、简易的、经济的有效解决方案.煤粉在储存、加工和运输过程中易于调节,然后经过进一步的安全处理,最终被铸造厂使用.尽管煤粉有诸多不足之处,对于最终用户来说,它仍然是经济合算的.而且现代加工和筛分方法确保它在最佳条件下使用.     

Effect of ultrasound treatment of AlSi5 liquid alloy on corrosion resistance

The application of power ultrasound to liquid alloys can be a simple and cost effective method to induce both degassing and grain refinement in a single step, without the need of inert gas or inoculants additions. In this paper, the treatment of liquid hypoeutectic AlSi5 alloy by ultrasound waves and its effects on microstructure were investigated. The corrosion behavior of ultrasound treated samples was compared to that of the non‐treated ones by means of immersion and electrochemical tests. It was observed that the ultrasound treated alloy offers better quality, higher mechanical properties and improved corrosion resistance, as a consequence of a more uniform distribution of the solute.     

模铸连浇中间包控流装置优化的水模实验

通过水力学模拟实验,优化了模铸连浇中间包控流装置。结果表明,安装控流装置,并将开孔设于挡墙下部正中间时,流体在中间包内的停留时间较长,死区体积最小,夹杂物上浮率也较高,而且不存在短路流。因此,经过控流装置优化,流体在中间包内的流场也得到明显改善,流动模式较合理,有利于钢中夹杂物的上浮去除,可以保证浇注大钢锭的质量。