Abstract:

The leakage ratio, compression recovery and stress-relaxation of flexible graphite corrugated metal composite gaskets with 316L and A3 steel as framework were tested on an automatic multi-function gasket testing rig. The effects of flexible graphite cover layer thickness, frame material and gasket stress on sealing performance and mechanical properties were investigated. The residual thickness of corrugated metal was determined at different thicknesses of cover layer and gasket stresses. The sealing performance of the composite gasket was mainly dependent upon the thickness of cover layer with flexible graphite, and optimal sealing performance was observed for the corrugated metal when the thickness of cover layer was 0.6 mm. The composite gaskets had good carrying capacity and sealing performance, which was especially suitable for complex applications, such as pressure and temperature fluctuations. Also outstanding recovery of the composite gaskets could be obtained by pre-compression. In addition, as gasket stress increased, sealing and compression recovery performance of 316L composite gaskets became obviously better than the composite gaskets with A3 steel as framework, and the former had distinct improvement than the latter in resisting stress relaxation and creep behavior.

Key words: composite gasket, flexible graphite, corrugated metal, sealing performance, monolith, optimal design, experimental validation

摘要：

在全自动垫片综合性能试验台上分别进行了316L和A3钢作为骨架材料的金属波纹复合垫片的泄漏率、压缩回弹性能和应力松弛试验,考察了柔性石墨覆盖层厚度、骨架材质和垫片应力对垫片密封性能和力学性能的影响,分析了不同覆盖层厚度和垫片应力下的金属波纹残余高度。结果表明:覆盖层厚度对垫片的密封性能有重要影响,厚度为0.6 mm时该类垫片的综合性能最佳;金属波纹复合垫片具有良好的承载能力和密封性能,尤其适宜压力波动、温度剧变等场合的密封,预压缩处理更能真实反映出复合垫片优异的回弹性能;此外,与A3钢作为骨架材料的复合垫片相比,316L复合垫片的密封性能和压缩回弹性能随垫片应力的增加逐渐显现,且其抗松弛能力和抗蠕变性能也得到了显著提高。

关键词: 复合增强垫片, 柔性石墨, 金属波纹, 密封性能, 整体器件, 优化设计, 实验验证