浅析γ辐射煤灰分仪的测量误差与改进

γ辐射煤灰分仪能够快速测定煤中灰分的百分含量,但其测量值与工业分析的化验灰分值存在较大的偏差.通过对影响γ辐射煤灰分仪测量结果的几个主要因素进行分析,以及对快灰煤样制备工艺上的改进,降低了快灰仪测量结果与化验结果的误差.     

软测量技术在钕铁硼氢粉碎工艺过程中的应用

氢粉碎工艺是制备高性能钕铁硼产品的必备手段,针对钕铁硼氢粉碎的原理和工艺过程,提出了利用软测量技术在线监测钕铁硼氢粉碎过程,从而优化氢粉碎工艺过程、缩短生产周期的思路与方法.详细阐述了软测量模型的建立方法,并通过MATLAB实现了模型的仿真验证.     

氮气携带熔融热导法测定钢中氢含量

利用熔融-热导法测量合金钢中氢的含量,在实验过程中,优化了各项分析参数,对不同钢种试样进行了精密度和准确度测试,证明该方法准确、快速,适合各类合金钢中氢含量的分析.     

高纯金属钛中微量氢的分析方法研究

采用高频感应热导法测定高纯金属钛中氢的质量分数.着重讨论了感应电流、坩埚类型、助熔剂、空白值、最小分析时间及样品质量对测定结果的影响,制定出了高纯金属钛中氢的分析方法.结果表明,该方法测定高纯金属钛试样中氢质量分数的相对标准偏差(RSD)为6.0%,加标回收率为98%～106%.利用综合测定程序,探讨了金属钛中氢分量的测试条件,并通过分峰实验计算了各氢分量的值.     

钢液氢含量检测技术研究

测量钢液氢含量的方法有离线定氢和在线定氢。离线定氢通过从钢液中取样,凝固后实验室检测氢含量。在线定氢通过测量出钢液的平衡氢分压后利用Sievert定律换算出氢含量。与离线定氢相比,在线定氢影响因素少,系统重现性好,测量周期短,满足真空处理、连铸等快节奏定氢的需要。     

连铸坯表面温度实时数据采集系统

为准确测量连铸生产过程中铸坯表面温度,开发出了基于Delphi7.0的在线红外测温系统.利用Delphi的微机串口通信功能,实现计算机和3台红外测温仪的通讯连接.通过Windows下的数据采集软件,实现了铸坯表面温度的显示、保存功能.实验结果表明,系统可准确测量铸坯表面温度.     

钢中氧氮氢同时测定方法中氢空白值的控制

针对钢中氧、氮、氢同时测定方法中氢测定结果较低温测氢法异常偏高的问题,进行了原因分析并提出了解决的办法。通过比较氢含量极低钢样的两种测定方法的氢结果,得出氧、氮、氢同时测定方法中石墨坩埚的氢杂质是造成上述问题的主要原因。为降低石墨坩埚中的氢杂质,实验提出将坩埚于450～480 ℃加热处理48 h用于日常分析,分析系统的氢空白值从0.69 μg/g 降低至0.12 μg/g,同时提高了方法的精密度,11次空白值的标准偏差为0.06 μg/g。按实验提出的方法对氢空白进行控制后,钢中氧、氮、氢同时测定方法中氢的分析结果与低温单独测氢法一致;钢中1.2～6.8 μg/g的氢测定结果,相对标准偏差(RSD,n=5)在1.0%～12.2%,满足炼钢炉前分析的要求。     

浅析γ辐射煤灰分仪的测量误差与改进

γ辐射煤灰分仪具有快速测定煤中灰分的百分含量,在确保烧结用无烟煤以及炼焦用精煤质量的前 提下,指导钢铁企业是否及时卸车。但其测量值与工业分析的化验灰分值存在较大的偏差,通过对影响γ辐 射煤灰分仪测量结果的几个主要因素进行分析,以及对快灰煤样制备工艺上的改进,从而达到降低其快灰仪 的测量结果与化验结果的误差。     

炼钢生产化验数据管理系统的开发与应用

针对传统炼钢生产过程中化验数据传输慢、误报率高等问题,利用了先进的网络技术、数据库技术,开发出炼钢生产化验数据管理系统。4年多的实际运行表明,该系统稳定可靠,操作简便,提高了炼钢化验数据的传递速度,缩短了冶炼时间,降低了生产成本。     

动态测量系统在螺纹钢生产中应用的可行性分析

结合动态测量系统在线材生产中的应用，对动态测量系统在螺纹钢生产中的应用进行可行性分析，从动态测量系统的基本原理、测量方式的选择、测量角度的确定、测量数据的分离、采样值取舍与数据分析、热态测量结果的修正、测量位置的选择和测量防护等方面说明动态测量系统在螺纹钢生产中应用是可行的。     

平炉钢用炉外精炼剂的研究

通过实验室及工业实验找到了较为适宜的精炼剂,其成分为75％CaO;10％Al_2O_3;10％CaF_2及5％Al。实验发现,每吨钢加入1kg精炼剂,可脱除0.002％S;温降较小。加入精炼剂的钢夹杂物含量明显降低。     

Submerged liquid slag injection in steel melt: scaleup study using cold model and dimensional analysis

Abstract

Submerged injection of solid flux powder is used in the steel industry to eliminate impurities in an economical way. The efficiency of such an injection process is limited by the fact that only a fraction of the injected particles penetrate into the liquid melt, while the majority remain as bubble encapsulated solids, causing poor heat and mass transfer. Therefore, liquid slag injection can be considered a potential alternative technique in the refining of steel to improve the efficacy of mass transfer in such a process. In the present work, liquid slag injection in a steel melt has been simulated by means of laboratory scale cold model experiments in which, water, paraffin oil and benzoic acid have been used as low temperature analogues for liquid steel, slag and impurities, respectively. Through dimensional analysis it is observed that the modified Froude number can be considered as a criterion for scaling up such a process from a bench scale to a full scale system. A regression analysis has also been carried out to correlate the dimensionless mass transfer rate constant with the relevant dimensionless numbers, namely, dimensionless gas velocity, Froude number, aspect ratio and non-dimensional lance depth.     

Cr12N高氮钢冶炼过程中氮的控制

在高温高压反应釜内冶炼Cr12N高氮钢,通过试验发现,在Cr12N的熔炼过程中,随着压力的提高,钢中的氮含量不断增加,钢锭中得到的固相中氮的饱和溶解度和Chipman等人的热力学模型计算得到的氮的饱和溶解度有一定的偏差,为了修正这个偏差,引进了Burton-Prim-Slichter方程,修正后得到液相中氮的饱和溶解度的修正值和计算值吻合得很好。计算了在Cr12N的冶炼过程中,防止气泡析出所需要的最小凝固压力为2.84 MPa,通过试验发现,在高的凝固压力下,钢锭的致密性和缩孔现象得到明显改善。     

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In order to accurately control the rare earth content in liquid steel in electroslag remelting (ESR) process, according to the ion and molecule coexistence theory (IMCT) of slag structure and corresponding phase diagrams, a thermodynamic calculating model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for La2O3-Al2O3-CaF2 slag system was formulated. The results show that the calculated values of NLa2O3 are in good agreement with the reported measured values, indicating that this calculating model can wholly embody the characteristics of the slag system. The activity of La2O3 decreases with the increasing of the Al2O3 and CaF2 content, and Al2O3 is stronger than CaF2 in decreasing the activity of La2O3. But the activity of La2O3 increase with the increasing in temperature at the composition range of 30% La2O3, 20% Al2O3, 50% CaF2. Above all, the activity of La2O3 in La2O3-Al2O3-CaF2 slag system can be quantitatively analyzed by this thermodynamic model, and this model can provide a theoretical basis for precisely controlling the lanthanum content in molten steel in ESR process.     

钢中氢含量的测定和分析

介绍了利用RH600氢分析仪测量钢中氢含量时,不同的氢含量标样和加工方法对测定值的影响,并利用所确定的最佳测试条件研究了钢中氢含量随时间的变化趋势。结果表明,试样在加工时,使用冷却液可减少结果偏差;钢中氢含量在一定时间内随放置时间的延长而降低。     

Computer algorithms for radiometric measurement of temperature during the galvanneal process

A set of computer algorithms has been developed to facilitate the measurement of temperature by radiometry during the galvannealing of steel strip. During the galvanneal process, the emissivity of the surface of the strip increases rapidly from a value of approximately 0.2 for the highly specular surface of the liquid zinc coating to a value as high as 0.8 for the surface of the diffuse intermetallic layer that is formed. Reliable noncontact measurement of temperature during galvannealing requires an approach that can accommodate and compensate for this large and rapid change in emissivity. The galvanneal process was simulated in 63 laboratory tests during which the temperature was measured by a thermocouple, and spectral radiance was measured using a dual-wavelength radiation thermometer (DWRT). The emissivity of the surface was obtained from these data. The tests were conducted at galvannealing temperatures of 753, 793, and 833 K and simulated line speeds of 60, 80, and 100 m/min. The laboratory data were used to develop a linear dual-wavelength emissivity compensation algorithm to infer the temperature of the strip to within ±20 K. The iron content of the galvannealed layers varied in the range 5 to 13 pct, and measurements of surface roughness gave arithmetic roughness values in the range 1 to 3 Μm. Formerly Graduate Research Assistant, School of Mechanical Engineering     

Constitutive Relationship of New Steel 33Mn2V and Its Application in Piercing Process by FEM Simulation

 Based on test data from the hot forge experiments on Gleeble 1500, a Kumar type constitutive equation for 33Mn2V steel is established. Applying this constitutive equation in commercial FEM software of MSC/SuperForm 2005, the piercing process of 33Mn2V steel in Mannesmann mill is then simulated. The modeling results visualized the dynamic evolution of equivalent stress, especially inside the workpiece. It is shown that the non-uniform distribution of stress on the internal and external surface of the workpiece is a distinct characteristic of processing tube piercing. The numerical model was verified by comparing the values of calculated force parameters of the piercing process with those measured in laboratory conditions. And it shows that the Kumar-type constitutive relationship meets the practical needs.     

AOD冶炼不锈钢工艺模型的研究

以45t AOD-L冶炼304不锈钢的实际生产数据为依据,根据系统模化、质量、能量守恒及热力学原理,建立了AOD冶炼奥氏体不锈钢的工艺模型(AOD M&H),包含操作、化学反应、冶金计量和热化学计量4个层次,共涉及469个变量。使用该模型进行模拟,由139项输入变量,包括各物料的用量、成分和温度,可方便地求出39项输出变量,如钢液成分、温度等。应用结果表明,冶炼过程中各阶段的钢液碳含量与温度的预报值和实测值的相对误差≤11.1%。     

非真空吹氮工艺对316L奥氏体不锈钢吸氮行为的影响

在实验室通过刚玉坩埚-硅钼棒电阻炉研究了吹氮时间(0～50 min),氮气分压(35～100kPa),吹氮流量(总流量0.3 L/min;N₂:Ar=1:3～3:1),钢液温度(1 773～1 833 K)对0.8 kg 316 L不锈钢液(%:0.031C、16.13Cr、10.12Ni、2.12Mo)中氮含量的影响。结果表明,钢中氮含量随着吹氮时间、氮分压的增加而增大,随吹氮流量增加钢液氮含量达到饱和的时间缩短,氮的溶解度随着钢液温度的降低而升高。应用热力学模型和动力学模型对实验结果进行分析。     

反向凝固法生产复合奥氏体不锈钢薄带的研究

采用１．２ｍｍ厚的１５Ｆ热轧板为母带,以奥氏体不锈钢１Ｃｒ１８Ｎｉ９作为覆层材料,在实验室条件下研究了反向凝固法生产复合奥氏体不锈钢薄带的可行性。实验表明,随着母带在钢液中浸渍时间的增加,新相层的生长经历“快速生长”、“平衡相持”和“迅速回熔”阶段,新相层厚度着钢液过热度的增加而近似线笥地减少。此外,线带表面状态、母带在钢液中的浸渍时间及过热度对铸带质量有显著影响,控制合适的工艺参数可以获得质量优