Nondestructive Flaw Detection and Density Measurements in Powder Metallurgy Parts

粉末冶金（P/M）在净形或近净形成形零件上的应用正以非常迅速的速度扩大。这一增长是由于与传统的冶金和机械加工工艺相比，使用粉末冶金技术可以节省大量劳动力、材料和能源。粉末冶金的优点是，它是一种非常快速和经济的净形状和接近净形状零件的生产者，同时比铸造、锻造或机加工使用更少的能源。开发一种可靠、经济的无损检测方法，能够检测出影响零件性能的裂纹、层合和其他参数，可以大大提高粉末冶金零件的质量和可靠性。最近进行的工作表明，涡流法在粉末冶金零件的无损检测中具有良好的潜力。同样明显的是，粉末冶金零件的涡流响应通常比传统冶金零件复杂得多，需要进行额外的研究，以便将涡流技术常规应用于粉末冶金零件，特别是绿色或未烧结的粉末冶金零件。本研究旨在开发涡流技术（探头、仪器、数据处理和测试程序），以实现粉末冶金零件的常规检查。测试仪器将以通用的、计算机为主的多频仪器为主。在黑色金属和有色金属、生坯和烧结粉末冶金零件中，使用基于计算机的涡流方法检测裂纹和其他异常、测量密度和其他变量的可行性将得到证明。

9360313 Johnson The use of powder metallurgy (P/M) for net or near net shaped formed parts is expanding at a very rapid rate. This growth is due to the major savings in labor, materials and energy that can arise from the use of P/M technology compared to conventional metallurgical and machining processes. P/M has the advantage of being a very rapid and economic producer of net shape and near net shape parts, while using less energy than casting, forging, or machining. The quality and reliability of P/M parts could be improved dramatically by the development of a reliable and economic nondestructive inspection method capable of detecting cracks, laminations and other parameters effecting part performance. Recent work conducted indicates that eddy current methods have excellent potential for nondestructive inspection of P/M parts. It is also evident that eddy current responses from P/M parts are often much more complex than from conventional metallurgical parts and additional research is required to permit application of eddy current technology routinely to P/M parts, particularly green or unsintered P/M parts. This research is to develop the eddy current technology (probes, instrumentation, data processing, and test procedures) necessary to permit routine inspection of P/M parts. The test instrumentation will be based on a general purpose, computer based, multi frequency instrument. The feasibility of using computer based eddy current methods to detect cracks and other anomalies, and measure density and other variables, in both ferrous and non ferrous, green and sintered P/M parts will be demonstrated.