大尺寸高相对密度钨管的制备

Fabrication of large size and high relative density tungsten tube

大尺寸高相对密度钨管制品对于石英熔炼行业具有重要的应用价值,为了克服大尺寸钨管在制备过程中易出现压坯开裂和相对密度不高的问题,对不同粒度钨粉进行了掺混实验,研究了混合时间对压坯强度的影响。研究表明,对掺混钨粉进行气流破碎处理,可以有效地缩小粒度分布范围,提高颗粒均匀性。通过对压制压强和保压时间的研究,发现压制压强>230 MPa时,延长保压时间或提高压制压强并不会提高压坯强度。通过慢速升温烧结实验,发现钨管收缩率较大的温度集中在1600℃以下,延长中低温烧结时间可以较好的提高钨管的相对密度。

The tungsten tube products with the large size and high relative density have the important application in the quartz smelting industry.To overcome the problems of cracking and low relative density in the preparation process of the large size tungsten tube,the mixing experiments of tungsten powders with the different particle sizes were carried out,and the effect of mixing time on the compaction strength was studied.It is found that the particle size distribution can be effectively reduced and the particle uniformity can be improved by the further air crushing treatment for the mixed tungsten powders.When the pressing pressure is more than 230 MPa,the compaction strength will not be improved by prolonging the holding time or increasing the pressing pressure.The temperature for the tungsten tube with the higher shrinkage rate concentrates below 1600℃in the sintering experiment by slow temperature rising.Therefore,the relative density of the tungsten tube can be improved by prolonging the sintering time at medium and low temperature.