浅论电工钢焊缝质量优化

从焊缝质量不良（或焊缝断带）产生原因分析入手,通过对比得出焊接工艺及参数的调整对电工钢焊缝质量的影响。阐述了其改善措施及改进效果。     

浅谈电工钢焊缝质量优化

本文从焊缝质量不良（或焊缝断带）产生原因分析入手，通过对比得出焊接工艺及参数的调整对电工钢焊缝质量的影响。介绍涟钢针对电工钢焊缝断带采取的改善措施及改进效果，从原理出发，阐述每一步改进措施的必要性。     

冰箱压缩机使用电工钢的状况及质量改进意见

调研了我国冰箱压缩机产销现状，指出了所使用的电工钢牌号、质量和数量，给出了武钢和日本电工钢研制状况，提出了冰箱压缩机用电工钢质量改进意见。     

我国电工钢生产现状及发展建议

叙述了目前我国电工钢生产发展状况,2003年我国热轧电工钢产量93.8万t,冷轧无取向电工钢90.6万t,取向硅钢片12.53万t,同时与先进国家的电工钢状况进行比较,产品牌号与质量有15～20年差距;对我国电工钢需求量进行了预测,2005年缺口150万t以上;对我国今后电工钢发展,提出了5点建议.     

电工钢生产中硫的控制

针对攀钢高硫铁水冶炼现状,结合不同生产工艺路线,论述了攀钢近年来为实现低硫电工钢的生产,在铁水预处理、转炉冶炼、钢水精炼过程中硫控制技术的开发与应用,形成了低硫洁净钢生产工艺技术,实现了低硫电工钢的生产.低硫电工钢RH脱硫率可达到20％左右,成品[S]控制在0.006％左右.     

无取向电工钢连续退火模拟在生产中的应用

应用MULTIPAS连续退火机试验机,对冷轧无取向电工钢进行连续退火工艺模拟,通过对试验工艺的不断完善,实现了对无取向电工钢连续退火温度曲线、张力的模拟,通过有效的板形控制措施,试验样板板形完全满足单片磁性能检测和力学性能检测需要,从而使该模拟方法模拟的试验结果超出纯理论研究的范畴,能够有效应用到生产实践中。     

薄板坯连铸连轧工艺与电工钢生产

介绍国内外采用薄板坯连铸连轧流程生产电工钢的现状，阐述该工艺流程生产电工钢的独特优势，介绍生产无取向电工钢遇到的实际困难，总结采用该流程生产晶粒取向电工钢的工艺特点。指出采用该工艺生产电工钢需要克服的技术难点和研究方向。     

电工钢生产中的涂层控制技术

在电工钢生产中，电绝缘涂层的质量十分重要，而市场对产品的要求越来越高，在扩大涂层范围的基础上，同时还要保证更加紧密的涂层厚度公差。为了满足这些主要因素，设备制造商不断改进涂层设备和相关的控制系统。本文报道了最近一套适用无取向电工钢的四辊涂层设备投产情况，以及所采用的专用自动涂层程序控制系统。同时，也记述了主要的结果和发展趁势。     

Evaluation of the electrical resistivity of steels

Literature data on the physical properties of steels have been collected and put into a database. The resistivity of steels has been analyzed as a function of composition and microstructure. An overview over former studies is given. The steels have been investigated in two groups, ferritic steels and austenitic steels. A thermodynamic analysis with ThermoCalc has been performed. Regression analysis on the influence of composition on the resistivity was then carried out. The results for ferritic steels are: Si and Al have the highest elemental resistivity, followed by Mn, Cu, Ni, Mo, and Cr. C precipitated in cementite shows a high coefficient in the analysis when the amount of Fe bound in cementite is not considered separately. C in solution with ferrite shows no significant effect. Cr bound in cementite shows a significant effect but Mn, though present in cementite in comparable amounts, has no significant effect on the resistivity. N and C have the highest elemental resistivity in austenite, followed by the substitutional solutes Nb, Si, Ti, Cu, Ni, Mo, and Cr. The carbides NbC and TiC appear with a higher coefficient in the regression model than can be explained by phase‐mixture models providing upper and lower bounds for the resistivity of two‐phase alloys. Cr₂₃C₆ shows no significant effect. The regression results can be used to predict the resistivity of steels with known composition. The model predicts the resistivity of ferritic steels with a maximum deviation between experimental and computed value of 12 nōm and a standard deviation of 5.6 nōm. For austenitic steels, the model prediction shows a maximum deviation of 52 μōcm and a standard deviation of 20 nōm.     

Strain-induced nucleation of MnS in electrical steels

The nucleation of MnS was investigated during the creep of electrical steels. Precipitation start(P _s) times were measured in the temperature range from 800 °C to 1100 °C. Direct evidence regarding the locations of the nucleation sites was obtained by means of electron microscopy. The results show that both dislocations and grain boundaries act as nucleation sites for such strain-induced precipitation. The experimental data were analyzed using classical nucleation theory, on the basis of which it is demonstrated that nucleation at grain boundaries is dominant at the higher testing temperatures. TheP _s values in this temperature range are determined by the corresponding nucleation rate. As the temperature is decreased, however, nucleation on dislocations becomes more important. This is due to the additional driving force contributed by deformation-induced vacancies, as well as because the higher dislocation densities at the lower temperatures provide a higher density of potential nucleation sites. In addition, the influence of the growth of these particles following nucleation is considered in the analysis pertaining to theP _s curves.     

生产微合金化钢的几点考虑

在20世纪60～80年代,连续浇铸是钢铁工业的一项重要的工艺变革。这项技术无论对提高炼钢生产效率还是改善产品质量都产生了深刻的影响。然而,为保持产品竞争力和成本效益,需要一个统筹的炼钢方法。从铁水生产开始或者从冶炼开始,经过精炼到连铸,再到轧钢和后续工序,钢产品的整条生产路线应该整体可控。关于连铸,有2个实例可以说明这种发展趋势:改进中间包设计和冶金技术,优化浸入式水口和高水平的结晶器液面控制。无止境的洁净钢研究已经从连铸机本身转到钢包冶金。同样,无缺陷表面质量研究不再简单地专注于连铸技术,同时也将炼钢考虑进去。随着结构钢品种的合金设计转变,从普通的中碳锰钢到裂纹敏感的现代低碳微合金化HSLA钢,连铸机的设计和技术发展并驾齐驱。     

Orientation selective recrystallization of nonoriented electrical steels

A nonoriented electrical steel that was commercially hot rolled and then given a 70 pct cold reduction on a laboratory mill was annealed at 680 °C for 6 minutes. The sheet was then submitted to a second rolling reduction of 5.2 pct, followed in turn by a second annealing at 730 °C for various times. The textures were measured after the first and second recrystallization treatments and analyzed using a nucleation and growth model. In the model, the nucleus orientation distribution function is first calculated by assessing the nucleation probability for each deformed matrix orientation. The nucleation texture is then transformed into the recrystallization texture by means of an appropriate growth criterion. The calculations indicate that the annealing texture of the conventionally rolled (70 pct reduction) sheet can be accounted for on the basis of random nucleation followed by selective growth. The latter is characterized by the following physical features: (a) the low mobility of low angle grain boundaries, (b) the enhanced mobility of {110} plane matching boundaries, and (c) variant selection of the (110) plane that carries the largest amount of slip during deformation. The computer simulations also show that low stored energy nucleation is favored in the lightly rolled sheet. These nuclei grow into the matrix by a selection mechanism that involves the increased mobility of 219a and 233a (110) coincident site lattice (CSL) boundaries.