Viscosity estimation for slags containing calcium fluoride

Based on recently published experimental data, the Riboud model was modified for viscosity estimation of the slags containing calcium fluoride. The estimated values were in good agreement with measured data. Reasonable estimation can be achieved using the modified Riboud model for mould fluxes and ESR (eletro slag remelting) slags. Especially for ESR slags, the modified Riboud model can provide much more precise values than the original Riboud model.     

Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties

A series of high nitrogen austenitic stainless steels were successfully developed with a pressurized electroslag remelting furnace. Nitride additives and deoxidizer were packed into the stainless steel pipes, and then the stainless steel pipes were welded on the surface of an electrode with low nitrogen content to prepare a compound electrode. Using Si3N4 as a nitrogen alloying source, the silicon contents in the ingots were prone to be out of the specification range, the electric current fluctuated greatly...     

激光重熔制备TA1表面Ni/Al复合抗高温氧化涂层

为了提高纯钛的高温抗氧化性能,采用电弧喷涂和等离子喷涂方法在纯钛表面制备Ni/Al复合涂层.利用激光重熔使得Ni层与Al层发生冶金反应,对试件进行800℃×40 h连续氧化.根据生成的金属间化合物特征研究纯钛的高温抗氧化行为.结果表明,经过表面改性处理后Ni/Al复合涂层可以显著提高纯钛的高温抗氧化性能.在激光重熔过程中Ni/Al复合涂层中的Al发生熔化扩散并与Ni形成以Ni₂Al₃相为主的扩散层.在氧化过程中Ni/Al复合涂层表面形成连续且致密的α-Al₂O₃氧化膜与大量NiAl相,表面扩散层中的富铝相可为表面提供充足的Al元素,进而对纯钛基体提供有效的高温抗氧化保护作用.     

Ti表面改性Al涂层及其抗氧化性能

为了提高钛材的抗高温氧化性能,利用电弧喷涂工艺方法在工业纯钛表面制备了纯Al涂层,对喷涂态纯Al涂层分别进行炉中加热及激光重熔改性处理,以得到具有一定抗高温氧化性能的Ti-Al金属间化合物涂层.对改性处理后的试件进行了800℃/60 h的氧化试验.结果表明,经750℃/5 h炉中加热改性处理后,钛基体表面可形成厚约300μm的TiAl_3金属间化合物层,而经激光重熔改性处理后,钛基体表面形成的TiAl_3金属间化合物层较薄.经高温氧化试验后,炉中加热改性Al涂层的微观组织形貌未发生明显变化,而激光重熔改性Al涂层的微观组织形貌变化较为明显.相比于激光重熔改性处理,经炉中加热改性处理后Al/Ti试件的抗高温氧化性能更佳.     

激光重熔等离子喷涂涂层研究现状与展望

综述了等离子喷涂涂层的激光重熔表面技术的研究现状,从激光重熔机理和等离子喷涂涂层的特征,分析了激光重熔后涂层的组织结构和性能变化,介绍了激光重熔的数值模拟,探讨了激光重熔等离子喷涂层工艺过程中存在的一些问题和解决途径以及今后的发展方向.     

高迁移率GaAs外延片制备的研究

提出了在ＧａＡｓ液相外延过程中，采用生长高纯度缓冲层、高温烘烤生长系统以及回熔衬底片等工艺，获得具有电参数ｎ＝１０１６～１０１７ｃｍ－３，μ＝４～５×１０３ｃｍ２／ｖ·ｓ（３００Ｋ）的ＧａＡｓ液相外延片．总结出生长高迁移率ＧａＡｓ外延片的制备方法．     

喷涂零件直径与重熔转速关系探讨

本文研究对回转体零件表面进行氧乙炔焰自熔合金粉末二步法喷熔，用火焰对涂层作重熔处理时，零件的旋转速度对涂层重溶质量的影响。通过试验，建立最低重熔转速数学模型和最高重熔转速数学模型，并根据数学模型绘制出能指导生产的ｎ—Ｄ曲线。     

CuCr触头材料电弧重熔实验结果及分析

对粉末冶金法制得的CuCr触头材料进行了电弧重熔实验 ,对实验结果进行了分析     

激光表面重熔等离子喷涂陶瓷涂层的研究与发展

总结了等离子喷涂陶瓷涂层的缺欠以及激光重熔等离子喷涂陶涂层所存在的问题,在分析问题产生原因的基础上,提出了防止激光重熔等离子喷涂陶瓷涂层裂纹,气孔和剥等问题的同时指出了激光了涂陶瓷涂层的发展趋势。     

High Nitrogen Austenitic Stainless Steels Manufactured by Nitrogen Gas Alloying and Adding Nitrided Ferroalloys

 A simple and feasible method for the production of high nitrogen austenitic stainless steels involves nitrogen gas alloying and adding nitrided ferroalloys under normal atmospheric conditions. Alloying by nitrogen gas bubbling in Fe Cr Mn Mo series alloys was carried out in MoSi2 resistance furnace and air induction furnace under normal atmospheric conditions. The results showed that nitrogen alloying could be accelerated by increasing nitrogen gas flow rate, prolonging residence time of bubbles, increasing gas/molten steel interfaces, and decreasing the sulphur and oxygen contents in molten steel. Nitrogen content of 069% in 18Cr18Mn was obtained using air induction furnace by bubbling of nitrogen gas from porous plug. In addition, the nickel free, high nitrogen austenitic stainless steels with sound and compact macrostructure had been produced in the laboratory using vacuum induction furnace and electroslag remelting furnace under nitrogen atmosphere by the addition of nitrided alloy with the maximum nitrogen content of 081%. Pores were observed in the ingots obtained by melting and casting in vacuum induction furnace with the addition of nitrided ferroalloys and under nitrogen atmosphere. After electroslag remelting of the cast ingots, they were all sound and were free of pores. The yield of nitrogen increased with the decrease of melting rate in the ESR process. Due to electroslag remelting under nitrogen atmosphere and the consequential addition of aluminum as deoxidizer to the slag, the loss of manganese decreased obviously. There existed mainly irregular Al2O3 inclusions and MnS inclusions in ESR ingots, and the size of most of the inclusions was less than 5 μm. After homogenization of the hot rolled plate at 1 150 ℃×1 h followed by water quenching, the microstructure consisted of homogeneous austenite.