摘要
在GIS(气体绝缘金属封闭开关设备)铸件开发和应用过程中,ZL101A铝合金铸件出现缩松、冷隔、气孔等缺陷。缩松和冷隔缺陷严重劣化铸件的强度,影响GIS产品整体质量。本文结合GIS铝合金铸件开发试验及工程应用案例,对铸造铝合金含缺陷的断口、组织结构、强度进行分析与研究。结果表明:缩松和冷隔是诱发产品漏气和断裂的主要原因,尤其是海绵状缩松和大尺寸冷隔,极易造成应力集中,导致强度大幅度下降。缩松缺陷面积对抗拉强度的影响曲线可以分三个区域:快速下降区、平缓区和快速下降区,同时随缩松缺陷面积增大,伸长率呈线性下降趋势。局部弥散分布的芝麻状气孔(针孔)对铝合金壳体气密性和强度基本没有影响,通过应力(应变)电测试验进一步表明在水压试验的升降压过程中气孔对应力变化影响很小,铸件整体强度能够满足使用要求。
ZL101 A aluminum alloy castings have shrinkage porosity,cold shuts,air hole and other defects during the development and application of GIS(gas insulated metal closed switchgear)castings.The shrinkage porosity and cold shut defects seriously degrade the strength of castings,affecting the overall quality of GIS products.Combined with GIS aluminum alloy casting development test and engineering application cases,the fracture surface,microstructure and strength of casting aluminum alloy containing defects were analyzed and studied.The results show that shrinkage porosity and cold shut are the main causes of gas leakage and fracture of products,especially sponge shrinkage porosity and large-scale cold shut are easy to cause stress concentration,which leads to a large decrease in strength.The effect curve of shrinkage porosity defect area on tensile strength can be divided into three regions:rapid decline zone,gentle zone and rapid drop zone.At the same time,the elongation decreases linearly with the increase of shrinkage porosity defect area.The air hole(pinhole)with local dispersed sesame state has no effect on the air tightness and strength of aluminum alloy shell.Through the test of stress(strain)electrical measurement,it is further shown that the influence of air hole on stress change is very small during the pressure rise and fall during hydraulic pressure test process,and the overall strength of the casting can meet the use requirements.
作者
杨姣龙
骆常璐
孙明道
史峰涛
龚咪咪
高振奎
YANG Jiaolong;LUO Changlu;SUN Mingdao;SHI Fengtao;GONG Mimi;GAO Zhenkui(Pinggao Group Co.,Ltd.,Pingdingshan 467013,China;Henan Pingzhi High-voltage Switchgear Co.,Ltd.,Pingdingshan 467013,China)
出处
《热加工工艺》
北大核心
2021年第9期156-162,共7页
Hot Working Technology
基金
国家电网科技项目(PGKJ2018-200)。
