除气剂和超声波对Al-1.65%Si铸锭除气的影响

研究了除气剂和超声波对Al-1．65％Si铸锭除气的影响，如：没有添加除气剂和超声波处理、只添加除气剂不进行超声波处理、即添加除气剂又进行超声波处理的情况。分析了超声波除气效果的原因。研究结果表明，采用超声波振动处理的方法，可显著地降低铸锭内的含气量。     

超声波处理时间对工业纯铝铸锭结晶组织的影响

研究了超声波处理时间对工业纯铝铸锭结晶组织的影响，即添加除气剂又进行超声波处理的情况。分析了超声波对工业纯铝结晶组织影响的原因。研究结果表明。采用合适的超声波处理时间，可以提高工业纯铝铸锭的细化率。     

旋转喷吹除气装置原理及两种除气装置在应用中的对比

为了降低铝合金熔体中氢含量,提高金属纯洁度,从而提高铝合金铸锭冶金质量,我单位购置了国内外两种除气净化装置,通过合理使用,达到了满意的除气效果,保证了铸锭的,台金质量。本文研究了在线除气装置的除气净化原理,从多个方面对比了两种装置的优缺点。     

超声外场对不同温控状态下ZL205A铝合金凝固规律的影响

采用不同的超声外场处理熔体工艺, 研究了其对铸锭质量的作用机理与改善效果. 针对保温(750℃)和空冷(从750℃空冷7 min 10 s至约650℃)两种不同温控状态下的ZL205A铝合金熔体, 分别进行相同参数的超声场处理, 研究超声场对凝固组织的影响规律, 并利用力学拉伸实验进行验证. 研究结果表明: 在保温状态下对熔体施加超声处理, 具有较好的除气与改善第二相组织分布的效果; 在空冷状态下施加超声处理则可以消除集中缩孔, 显著细化晶粒; 当在保温和空冷条件下全程采用超声处理, 铸锭内部质量的改善效果最佳. 力学性能的测试结果与铸锭凝固组织的变化规律具有一致性, 验证了上述结论. 综上, 对不同温控状态下的熔体施加超声处理, 对熔体凝固过程的影响不同, 对铸锭内部质量的改善效果也各有侧重.      

熔铸工艺对1420铝锂合金铸锭氢含量的影响

分析研究了Al-Mg-Li-Zr系1420铝锂合金氩气及真空熔炼的除气原理,以及氩气与熔剂不同保护铸造的除气机理,认为熔体经真空精炼后在熔剂保护不铸造更有利于达到除气的目的,能显著降低铸锭的氢含量,提高铸锭质量。     

铝液在线除气净化箱体的设计

为了减少铝液铸锭中的氢含量和固体非金属夹杂物,运城市关铝设备材料有限公司设计了一种铝液在线净化除气装置除气效率高,对铝合金溶液有显著净化效果.     

用电解铝液生产铝合金扁锭的熔体净化

电解铝液温度高、夹杂物多、气体含量高.用电解铝液直接生产铝合金扁铸锭时,采取熔体预处理、两次炉内精炼、炉外在线除气除渣等熔体净化处理措施,可以获得纯洁度高的铝合金熔体.     

超声处理对高碳钢铸锭内气孔的影响

 研究了超声处理对高碳钢铸锭内气孔的影响。研究结果表明,在1 510 ℃较低温度的高碳钢液中进行超声处理后,铸锭内产生大量气孔;增大超声波功率、提高超声处理温度、采用冷却速度相对较慢的随炉冷却方式均可以降低超声处理后铸锭中气孔率。在1 570 ℃的较高温度下,超声处理具有一定程度的脱气作用,可以明显降低高碳钢铸锭中氮的质量分数,由未经超声处理时的97×10-6降低到处理后的49×10-6。     

不同熔化方式对2A14g铝合金圆铸锭质量的影响

对不同熔化方式生产的2A14g铝合金圆铸锭进行了质量全分析,结果表明,液体料铸造时使用在线除气过滤设备与固体料铸造时不使用除气过滤设备生产的同种合金铸锭,无论是显微组织还是综合力学性能差异不大,均能满足用户使用要求。     

各种因素对铝合金超声波铸锭等轴晶占有率的影响

以超声波探针顶上导入方式为例,讨论了金属熔体、超声波参数、探针和铸型等一系列因素对铝合金铸锭等轴晶占有率的影响,并对超声细晶机理进行了探讨。结果表明:金属超声铸锭的细化能力与自身的化学成分有关;随着超声波功率和处理时间的增加,等轴晶占有率提高,但是增加到一定峰值后开始下降;超声波探针应置于液面对称中心的位置,且浸入较小深度为宜;对于不同体积的铸型,存在一个最佳的径高比。     

Evaluation of internal and subsurface quality of continuously cast billets and slabs by ultrasonic techniques

Abstract

The paper highlights the developments made in ultrasonic techniques at R&D and SS Division of Tata Steel Ltd in detecting, measuring and analysing the continuously cast billets/slabs with respect to its internal as well as subsurface quality. Different continuously cast billets and slabs could be ranked according to their cleanliness levels even with the conventional ultrasonic flaw detector. The effectiveness of ladle furnace treatment and vacuum degassing (RH degassing) in improving cleanliness level in slabs of extra deep drawing grade and that of electromagnetic stirring in low and high carbon billets, could be successfully assessed using these techniques. In order to convert the down graded first and last slabs of a sequence of auto grade interstial free into the prime grade slabs, the scarfing depth and cutting length were optimised based on the ultrasonic results. Some results using a computer controlled ultrasonic multiscan imaging system, on continuously cast steel billets, have also been presented.     

RH真空循环脱气装置水模型循环流量的实验分析

循环流量是判断RH真空脱气装置冶炼效率的最重要的指标之一。本文中采取了两种方法－－超声波流量计法和粒子示踪法对RH真空脱气装置的水模型的循环流量进行测量分析，同时也研究了新型的多管RH装置的循环流动，比较新型装置同传统装置的循环流动的差别。结果表明：利用超声波流量计和粒子示踪法两种方法测量的结果都显示新型多管RH真空脱气装置循环流量大于传统的两管RH装置循环流量，并且，随着喷入气体量的增加，新装置循环流量的增加幅度也大于传统装置的增加幅度。     

Technology for out-of-furnace treatment of steel with the use of a new deoxidizer

A technology has been proposed for obtaining rolled plates with the use of calcium carbide instead of vacuum degassing. The technology makes it possible to obtain steel that is equivalent to vacuum-degassed steel with respect to the composition and quantity of nonmetallic inclusions and the quality of the finished plates. It is shown that the use of calcium carbide reduces the content of nonmetallic inclusions by a factor of roughly 1.5 compared to use of the standard technology without vacuum degassing. The percentage of hot-rolled plates rejected for defects detected in ultrasonic tests is also decreased.     

Effect of Top Slag Composition on Inclusion Characteristics during Vacuum Degassing of Tool Steel

The focus of the study was to investigate the effect of the chemical composition of the top slag on the inclusion chemical composition during vacuum treatment of a plastic mould tool steel. Sampling was done before and after vacuum degassing. The chemical composition of the inclusions was determined by using SEM combined with EDX. The results showed that several inclusion compositions were found before vacuum degassing, while only one main composition of inclusions was present after vacuum degassing. Furthermore, the composition of the top slag was found to have a great influence on the composition of the inclusions found in samples taken after vacuum degassing. The present study also shows that the vacuum degassing effectively reduces the number of inclusions in steel. Finally, the thermodynamic calculations of the activities using Wagner's equation were found to predict a lower oxygen activity value than the calculations made using the Thermo‐Calc software.     

Vacuum degassing of chromium-nickel-molybdenum steel at the Magnitogorsk Metallurgical Combine

The Magnitogorsk Metallurgical Combine has conducted a study of the effect of technological factors on the hydrogen content of chromium-nickel-molybdenum steel after vacuum degassing. It was established that the most important factor is the hydrogen content of the steel before the degassing operation. The study also determined the effects of the circulation coefficient, the duration of the degassing operation, and the vacuum used in the treatment. __________ Translated from Metallurg, No. 7, pp. 68–69, July, 2006.     

汽车轮毂用S55C中碳轴承钢的开发与生产实践

采用120t BOF冶炼→ LF精炼→ RH真空处理→CCM连铸(240 mm×240mm)→Φ55mm和Φ60 mm棒材轧制工艺流程生产汽车轮毂用S55C中碳轴承钢(0.54％～0.56％C).转炉高拉碳,终点[C]≥0.10％,并配备下渣红外检测系统;LF精炼渣碱度控制在4.0～6.5;RH精炼在≤66.7 Pa的...     

Effect of oxidation treatment and surface filming on hydrogen degassing from TiH2

An experiment was carried out to determine the effects of oxidation treatment and surface filming on hydrogen degassing from TiH₂ during heating and at fixed temperatures. It was found that surface filming has a stronger effect than oxidation, through which the temperature corresponding to the degassing peak of TiH₂ moved from 638 °C to more than 680 °C and the degassing temperature range increased from 125 °C to 150 °C in the heating process. From the degassing measurements at fixed temperatures and the physics model, the diffusion coefficients of hydrogen were determined to be 0.3 to 3.0 times less than that of the original TiH₂.