High nitrogen steel powder for near net shape products

This study has been performed to relate the powder properties to the process parameters of the plasma-rotating-electrode-process (Prep). A regression equation for average powder diameter was acquired from the experimental data as . A model is developed to describe the nitrogen pick-up by the Prep. On the basis of this model an expression for nitrogen content of the powder produced is deduced as: The powder has a solidification structure of austenitic dendrites. The CrN precipitates, the amount of which is dependent upon the nitrogen content, can be found in the interdendritic areas. During the solution annealing the Cr₂N precipitation reaction occurs in both of the inter- and intradendrite.     

Modern processes of production of thin sheets and strips by continuous casting

The history of the development of producing thin sheets and strips by continuous casting methods is considered. The mechanism of this sheet formation during casting of steel in a two-roll continuous caster is described. The advantages of this process over the corresponding traditional technologies are discussed.     

论连铸设备在连铸生产中的地位和作用

本文对连铸设备对提高连铸生产效率、质量和效益的作用，连铸设备组成与连铸设备管理中几个主要问题，连铸装备水平的优化与提高，连铸工艺与设备的结合，抓好连铸设备人员培训等问题进行了论述。     

Steel flow and inclusion separation in continuous casting tundishes

A model for the calculation of flow patterns and inclusion separation in continuous casting tundishes is described. Velocity and turbulence fields for the liquid steel are calculated, assuming three-dimensional, turbulent steady-state flow. A transport equation for particles is solved, which takes into account buoyancy, convection und turbulent dispersion. Particle concentration fields and the percentage of removed particles are calculated as a function of particle rise velocity. The influence of increased tundish width and height and of dams and weirs on the rate of inclusion separation is investigated for a slab caster tundish. Non-dimensional representations and approximation expressions are discussed and used to compare the computed removal rates to measured values from literature.     

日本新日铁自主创新的连铸技术

介绍了新日铁自主创新的6项连铸技术,重点有:中间包等离子加热、多模式电磁搅拌、铸坯面压下、复合钢板坯连铸、超厚钢板新型连铸机和薄带铸轧等。分析认为,目前新日铁的传统连铸技术领先于世界,下一步发展目标是薄带连铸技术的推广与普及。指出学习和借鉴新日铁自主创新的连铸技术,对低成本制造顶级钢铁产品会有一定的促进作用。     

The shape of bubbles rising near the nozzle exit in molten metal baths

A previously developed multineedle electroresistivity probe was used to investigate the shape of bubbles generated at the exit of a central single-hole bottom nozzle in molten Wood’s metal and mercury baths. This probe is capable of detecting the vertical cross section of rising bubbles. The shape of bubbles just after the detachment from the nozzle exit was correlated as a function of a modified Reynolds number and a modified Weber number. Furthermore, the relations between the shape of bubbles and the radial distributions of bubble characteristics specified by gas holdup, bubble frequency, etc. were derived. As a result, it is possible to predict the shape of the bubbles by measuring the bubble characteristics with a conventional two-needle electroresistivity probe.     

莱钢连铸20CrMnTiH钢非金属夹杂物研究

利用大样电解法、LEO-1450型能谱分析仪和NEOPHOT-32型金相显微镜对连铸生产的20CrMnTiH钢中非金属夹杂物的种类、含量、来源、形状、尺寸及分布等进行了研究。结果表明,精炼前夹杂物数量多,颗粒较大,类型主要为硅钙、硅锰酸盐等;中间包中主要为硅酸盐类型的球形和玻璃状夹杂物;铸坯中主要为硅铝酸盐球形夹杂物。经LF精炼后,非金属夹杂物去除率可达99％以上。     

珠钢CSP连铸的生产实践

本文介绍珠钢CSP连铸投产一年多的生产实践,描述连铸主要设备及特点,对连铸工艺进行介绍及总结,特别是对于连铸开浇失败和漏钢,提出一些对策和措施。     

结晶器专家系统在凌钢连铸的应用

介绍了凌源钢铁集团股份有限公司转炉炼钢厂连铸机上安装的连铸结晶器专家系统.实际运行表明:该系统运行效果良好,既能有效防止粘结漏钢事故发生,又能帮助观测结晶器工艺参数的异常状况,优化保护渣以及其他连铸操作方案,减少了纵裂和粘结发生率.     

热态铸余渣返生产可行性分析

铸余渣综合利用是钢铁企业节能减排的重要方法.在分析铸余渣资源属性的基础上,结合炼钢工艺流程,研究了铸余渣返生产的工艺路径和关键技术,重点讨论了返生产过程中由于温降而产生的粘罐和铸余渣与铁水混兑时的喷爆问题,提出了通过调整钢水碳含量解决钢水粘罐问题的技术措施和通过实验室研究解决喷爆的思路.同时结合现场生产管理调度,分析了铸余渣返生产后的炼钢工艺优化方向,为铸余渣的资源化利用提供了依据.     

梅钢连铸生产中的增氮控制

氮在钢中通常是一种有害元素,钢中氮含量高会严重影响钢的高温强度和高温塑性,降低钢的深冲性能。在连铸环节,保护浇铸不当会导致钢水增氮。基于连铸生产的实绩,介绍了梅钢连铸生产中对钢水增氮的控制,通过分析钢水连铸过程中的增氮机理,调查梅钢连铸当前的增氮现状,查找出了连铸增氮的主要影响因素,并对连铸工序的生产工艺、设备、耐材等方面实施了改进,有效减少了连铸的增氮保留,减少了改钢损失,为高质量要求钢种的生产创造了条件。     

宣钢12流方坯连铸机生产实践与设备改进

介绍12流方坯连铸机生产、质量与设备改进情况,主要针对200 mm×285 mm规格的大断面连铸坯和150×150、165 mm×165 mm小断面连铸坯的生产问题,通过改进导向段、优化二次冷却、改进结晶器和喷淋管、优化操作要点等手段,使得铸坯质量有了很大改善,同时也使生产效率有了很大提高。     

全连铸生产钢包工艺的优化

论文介绍了炼钢厂钢包工艺的改进情况及对连铸生产顺行和提高透气砖使用次数带来的益处.     

Experimental investigation into kinematical flatness criterion and conditions for the formation of shape defects for strips in cold rolling

Already-existing and new kinematical flatness criteria are experimentally investigated. The effect that both the irregularity of friction conditions across the width of a strip and the mismatch factor for circumferential speed of rollers has on the variation in the geometrical shape is determined.