Expulsion is an undesired event during resistance spot welding because the weld quality deteriorates. It is the ejection of molten metal from the weld nugget which usually occurs due to applying a high current for a s...Expulsion is an undesired event during resistance spot welding because the weld quality deteriorates. It is the ejection of molten metal from the weld nugget which usually occurs due to applying a high current for a short welding time. Expulsion has a significant impact on the final yield strength of the weld, thus the detection and characterization of expulsion events is significant for the quality assurance of resistance spot welds. In this study, hardness mapping, using a scanning hardness machine, was used as a quality assurance technique for re- sistance spot welding. Hardness tests were conducted on a resistance spot welded sample to prepare a hardness map. The test results showed good correlation between the hardness map and metallographic cross sections. The technique also provided further fundamental understand- ing of the resistance spot welding process, especially regarding the occurrence of expulsion in the nugget.展开更多
我国融合教育面临高质量发展转型的关口,借鉴国外经验、推动和深化本土听障学生融合教育研究势在必行。运用CiteSpace软件,对1994—2023年Web of Science核心数据库中听障学生融合教育研究的174篇文献进行可视化分析。研究发现:文献数...我国融合教育面临高质量发展转型的关口,借鉴国外经验、推动和深化本土听障学生融合教育研究势在必行。运用CiteSpace软件,对1994—2023年Web of Science核心数据库中听障学生融合教育研究的174篇文献进行可视化分析。研究发现:文献数量总体呈波动上升的趋势,研究热点集中于辅听设备和辅听技术的应用、校园沟通以及学业成就研究。因此,建议研究内容上,从听障学生切身需求出发发掘新的研究课题,推动理论成果落地转化;研究对象上,拓展到使用手语的聋生的融合议题;研究方法上,采取跨学科视角和质性研究方法,深入探究现有研究热点。展开更多
文摘Expulsion is an undesired event during resistance spot welding because the weld quality deteriorates. It is the ejection of molten metal from the weld nugget which usually occurs due to applying a high current for a short welding time. Expulsion has a significant impact on the final yield strength of the weld, thus the detection and characterization of expulsion events is significant for the quality assurance of resistance spot welds. In this study, hardness mapping, using a scanning hardness machine, was used as a quality assurance technique for re- sistance spot welding. Hardness tests were conducted on a resistance spot welded sample to prepare a hardness map. The test results showed good correlation between the hardness map and metallographic cross sections. The technique also provided further fundamental understand- ing of the resistance spot welding process, especially regarding the occurrence of expulsion in the nugget.
文摘我国融合教育面临高质量发展转型的关口,借鉴国外经验、推动和深化本土听障学生融合教育研究势在必行。运用CiteSpace软件,对1994—2023年Web of Science核心数据库中听障学生融合教育研究的174篇文献进行可视化分析。研究发现:文献数量总体呈波动上升的趋势,研究热点集中于辅听设备和辅听技术的应用、校园沟通以及学业成就研究。因此,建议研究内容上,从听障学生切身需求出发发掘新的研究课题,推动理论成果落地转化;研究对象上,拓展到使用手语的聋生的融合议题;研究方法上,采取跨学科视角和质性研究方法,深入探究现有研究热点。
