国内外模具钢生产现状及发展

介绍了国内外模具钢生产与发展的现状，并对目前国内外模具钢的应用状况进行分析比较，提出我国模具钢生产存在的问题以及与国际模具钢水平的差距，探讨了我国模具钢生产发展的思路与策略。     

国内外模具钢的概况

从模具成型的发展趋势入手，引伸到模具钢的发展，着重论述了国内外模具钢技术标准的对比，部分新钢种的研制、技术装备情况的介绍。并进一步提出我国模具钢发展的建议。     

我国塑料模具钢的发展前景及应用现况

在简要介绍我国模具工业和模具钢概况的基础上，重点介绍了我国塑料模具钢的应用现状和发展概况，并提出面对模具钢市场需求，模具钢生产企业的应对措施．     

模具及模具钢发展现状与分析

本文介绍了模具及模具钢国内外发展现状、应用领域、市场前景、生产工艺及设备等方面的问题，指出了莱钢开发模具钢和发展模具加工的可行性及重要意义。     

长钢四生产区模具扁钢发展方向探讨

本文分析国内合金模具钢(以下模具钢都指合金模具钢)市场的供需和发展特点，长钢四生产区模具扁钢的生产、质量现状，以及长钢四生产区模具扁钢在国内模具钢市场的定位，结合四生产区的装备情况，提出四生产区模具扁钢的发展方向。     

模具钢的发展现状

本文概述了欧美和日本模具工业和模具钢的现状和发展，同时介绍了和分析了我国模具钢的生产工艺，产量和质量。     

H13挤压模具钢金相组织分析

本文对Ｈ１３挤压模具钢的锻造毛坯组织，调质处理组织，气体氮化组织进行了金相观察与分析。     

抚顺特殊钢公司模具钢车间设备特点

着重介绍了抚顺特钢公司模具钢车间国内配套设备及引进的５机架可逆式扁（方）钢连轧精轧机组的性能。     

新标准 新材质(下)

文章论述优质合金模具钢新标准的颁发必要性及迫切性,新标准的技术指标,先进之处及执行新标准的工艺要素。执行新标准的同时,必须重视钢材表面质量,重视钢厂与客户之间的供需关系、重视市场需求的性能更优的特色模具钢的技术开发。     

模具钢的现状与发展趋势

模具钢是制造模具的材料,其现状与发展反映了一个国家的工业水平。本文介绍国内外模具钢常用钢号及模具钢的发展概况,简述了国内模具钢生产、应用方面存在的主要问题及近期发展的重点与目标。 1.国外模具钢的现状与发展 工业发达国家的冷作模具钢、热作模具钢、塑料模具钢种类比较齐全,并已形成系     

Challenge to control mould heat transfer during thin slab casting

Abstract

At the thin slab caster of Tata Steel, IJmuiden, mild cooling mould powders were introduced with the aim to control the mould heat transfer during casting. These mild cooling mould powders are characterised by specific values of basicity, solidification point and chemical composition. Application of these mould powders resulted in a redistribution of mould heat transfer during casting, i.e. a reduced and more stable mould heat transfer in the critical upper part of the mould and an increased mould heat transfer in the lower part of the mould. The average mould heat transfer and hence the shell thickness at mould exit are comparable to the standard powder. The application of mild cooling mould powders also resulted in improved solidification behaviour of the steel shell. A thinner chill zone with smaller thickness variations was observed. Furthermore, it was found that the mould taper required optimisation to match the changes in shrinkage behaviour to ensure uniform solidification. The use of mild cooling powders was observed to give an increase in mould friction. Mould thermal monitoring indicated that the solid slag films fractured (sheeting) in the upper part of the mould. However, no operational problems were reported, which indicate that the first 200 mm under the steel meniscus is essential for initial solidification and for the formation of a homogeneous steel shell. All these findings can be understood by considering the crystallisation properties of the mould slag, which include the cooling rate. Mild cooling has been shown to provide uniform heat transfer and adequate lubrication for high speed thin slab casting.     

结晶器保护渣性能和使用工艺

对结晶器保护渣的性能作了描述；对结晶器保护渣的性能与工艺条件、钢种的优化匹配进行了探讨。     

Liquid steel flow in continuous casting machine: modelling and measurement

Abstract

Single phase (liquid steel) and two-phase (liquid steel and argon bubbles) three-dimensional computational fluid dynamic and heat transfer models were developed for the continuous casting machines of ArcelorMittal. The computational domains include tundishes, slide gates, submerged entry nozzles and moulds. The effects of buoyancy, tundish design, tundish practices, nozzle design and caster practices on flow structure were investigated. Mathematical modelling is discussed in detail. In addition, submeniscus velocity measurements in the slab caster mould are performed with the method of torque measurement. A consumable probe is inserted into the liquid steel meniscus from the top of the mould through mould powder and slag layer. The liquid steel flow applies a drag force to the probe, which then generates a torque. This torque value is measured and then converted back to velocity. The concept and challenges of the technique are discussed, and the effects of casting parameters on mould flow structure are investigated. Product quality in relation to real time meniscus velocity measurements is also discussed.     

F-free mould powders for low carbon steel slab casting – technological parameters and industrial trials

The choice of the mould powder for slab casting is a difficult task because mould powders have many important functions during the continuous casting of steel. CaF₂ is a key ingredient in conventional mould slags since it reduces the viscosity, the liquidus temperature and the break temperature. Fluorine in mould powders is undesirable from the environmental and health points of view due to the following reasons: (i) evolves easily from slags, producing health-injurious gaseous substances, such as hydrofluoric acid; (ii) creates problems for storage and utilisation of solid waste and (iii) causes machinery corrosion. Aim of the present work is to describe the development of a new F-free mould powder for low carbon steel slab casting replacing CaF₂ with B₂O₃. Laboratory tests and industrial trials were performed considering the technological parameters viscosity, break temperature and crystallisation tendency. From laboratory tests it was concluded that important technological parameters are similar when comparing the F-bearing mould powder (reference) and the new F-free B-bearing mould powder for low carbon steel slab casting: viscosity at 1300°C, break temperature, and crystallisation tendency. It was observed during industrial trials that a significant decrease of the submerged entry nozzle erosion was observed. The results were similar when comparing the F-bearing and the F-free performance: slag pool thickness measurements, melting behaviour, Al₂O₃ absorption, mould powder consumption and slabs superficial quality.     

铝镁合金压铸用高性能稀土模具新材料 RE528的开发

本文从铝镁合金压铸用模具材料的性能要求入手,分析了常规模具材料的问题与不足,并以4Cr5W2VSi钢为基础,通过加入稀土元素和优化成分设计,成功研发一种具备优异冶金质量和组织性能、高附加值的稀土RE528热作模具新材料,其性能大大优于一般模具材料,具有良好应用前景。     

结晶器溢钢事故分析及预防措施

介绍结晶器溢钢对ASP连铸机生产的危害,对其原因进行了系统分析。结果表明,钢中Al因二次氧化生成大量的Al2O3絮状夹杂物,在浇注过程中絮状Al2O3夹杂物在塞棒头部不断聚集,经钢流冲刷脱落,致使单位时间进入结晶器内的钢水量瞬间增加,从而导致结晶器发生溢流事故。济钢炼钢厂制定了相应的措施,溢钢事故大幅降低,取得了良好效果。     

奥氏体不锈钢板坯连铸结晶器锥度的优化

针对奥氏体不锈钢连铸中的质量问题 ,对太钢三炼钢 1260mm× 160mm板坯结晶器的锥度进行了分析。通过不锈钢铸坯在结晶器内收缩的计算和拉坯速度、过热度等工艺参数对铸坯收缩影响的分析 ,得出采用双锥度结晶器比单锥度结晶器更符合铸坯在结晶器内的收缩规律 :液面附近 80～200mm区域采用较大锥度 ,液面下 200～800mm的结晶器下部 ,采用较小锥度 ,并在此基础上设计了曲线锥度结晶器。生产试验表明 ,双锥度设计显著改善了铸坯质量 ,消除了窄面鼓肚和中间凹陷等缺陷     

薄板坯高速浇注用结晶器保护渣

结晶器发热型初始保护渣和球状颗粒保护渣的采用是墨西哥希尔萨钢CSP型薄板坯连铸机成功操作及产品质量良好的原因之一。结晶器中的钢液面上覆盖一层厚厚的未反应保护渣导致结晶器弯月面区域处于良好的热状态之中。