输油管线集肤效应电伴热的优化

在对比输油管线伴热输送方法的基础上,介绍了输油管线集肤效应电伴热(SECT)的基本构成。并通过对电伴热系统的优化设计,提出了输油管线沿线的分段等温集肤效应电伴热输送。为进一步优化设计集肤效应电伴热输油管线的伴热性能,搭建了20 m长的分段等温集肤效应电伴热输油管线实验台架,对分段等温集肤效应电伴热输油管线进行了系统测试。测试结果表明:应用分段等温集肤效应电伴热技术时集肤效应明显,可极大地提高伴热效率;在优选不同形状和尺寸的SECT加热管时,宜采用1.905 cm的圆形SECT加热管,此时阻抗值较大且穿线安装方便。分段等温SECT的不仅可以提高发热效率,减小施工难度,而且漏电压处于安全水平,能够达到节能、环保、高效、安全等目的,易于在中长距离黏油输油管线中推广应用。     

热作模具用Dievar钢奥氏体形成转变动力学

采用Gleeble热模拟试验测定了Dievar钢连续加热过程中奥氏体形成的动力学曲线（CHT）。然后,根据等温转变动力学与连续转变动力学间的关系计算求得奥氏体等温形成的动力学图（IHT）。并经计算机拟合求得奥氏体等温形成和转变量的方程式。     

葛粉的非等温动力学研究

利用TG/DTA技术,考察不同升温速率下葛粉的热分解特性,研究葛粉热分解动力学,运用Kissinger法、Coats-Redfern法和Achar法对非等温动力学数据进行了分析。研究结果表明：在氮气气氛下,葛粉在280℃左右开始分解,至400℃以上基本分解完毕,反应机理函数的积分形式和微分形式分别为：G（α）=[（1-α）-1/3-1]2和f（α）=3/2（1-α）4/3[（1-α）-1/3-1]-1,对应的机理为三维扩散模型。     

钻杆接头淬火裂纹分析

通过对钻杆接头淬火裂纹产生的位置、形状,从原材料、工艺设计等方面分析裂纹产生的原因,给出了减少钻杆接头淬火裂纹的措施和方法。     

感应热处理技术的进展

感应热处理的发展已经由过去机械式中频发电机组向晶体管中频电源发展 ;对于集大电流、高耐压和高频特性于一体的固态电路 ,晶体管成为很有发展前途的功率电子器件。功率半导体器件在今后将向着大容量化、高频化、驱动简单、低导通压降、模块化和功率集成化方向发展。淬火机床的发展采用变频调速电机 ,步进电机或伺服电机 ,通过滚珠丝杆传动 ,移动速度均匀、精确。使用计算机进行控制的自动淬火机床 ,屏幕显示工作状况 ,同时可故障报警或故障诊断。能量监控系统 ,工件加热温度的监控 ,采用PLC与NC控制已带普遍性。     

作为淬火冷却介质 自来水的两大缺点

多数工件用自来水淬火会开裂，淬裂的原因是众所周知的：自来水的低温冷却速度太快。这是自来水的一大缺点。     

Identification of Heat Transfer Coefficients by Use Conditions of Quenching Oil

Heat transfer coefficients of the quench medium are necessary for heat-treatment simulation. Cooling characteristics of quenching oil vary with kinds and usage greatly. Users are selecting oil solutions that come up to their desired hardness and quenching distortion requirements. In particular cooling performance rises by agitation and decompression. Therefore we identified a heat transfer coefficient by usage and kinds of quenching oil. Cooling characteristics are different greatly by a kind of quenching oil. A difference of a cooling characteristic by a kind of oil depends on a temperature range of a boiling stage and the maximum heat transfer coefficient mainly. On the other hand, in a convection stage, there are few changes in a boiling stage. Even if quenching oil temperature is changed, heat transfer coefficients do not change greatly. When quenching oil stirred, heat transfer coefficients of vapor blanket stage and a convection stage rise, but there are a few changes in a boiling stage. When quenching oil is decompressed a temperature range of a high heat transfer coefficient moves to the low temperature side. In addition, a heat transfer coefficient in a vapor blanket stage comes down. For precision improvement of heat-treatment simulation, it is important that the heat transfer coefficient is calculated in conformity to the on-site use reality.     

Elimination of Quench Cracking by Controlling Agitation Uniformity

Uniform agitation of the quenchant is a critically important control parameter in optimizing distortion control and reducing steel cracking. Quenching with ultrasonic agitation or in the presence of electrical and magnetic fields provide uniform agitation leading to improved uniformity of the stress fields within the metal not readily achievable with more traditional agitation methods such as propeller pumps and sprays. These methods provide the additional potential advantage of varying agitation throughout the cooling cycle to achieve a wide range of cooling profiles not readily achievable with quenchants and more traditional agitation systems currently in use.