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一、序言铸造零件,特别是灰铸铁或可锻铸铁等广泛用于发动机零件,结构用箱体,工程机械等领域。以数控机械为代表的自动化加工技术的进步,促使加工生产战向自动化、无人化迅速地发展。以此为背景,推动了铸造零件加工的自动化;但因加工后常发现有气孔等缺陷,使刀具易于折损,故不能实现完全无人化。以往铸造零件的缺陷探伤,大多采用 X 射线或γ射线法,而对超声波方法的研究则很少。究其原因是由于:探头结构上存在不灵敏区或近距离声场;表面粗糙而产生多次表面反射杂波干扰,材料内部石墨等产生的散射;衰减或由此而引起 S/N 的下降等许多问题。
First, the preamble Foundry parts, especially gray cast iron or malleable iron are widely used in engine parts, structural box, construction machinery and other fields. The progress of automated processing technology represented by numerical control machinery has prompted the production and processing automation of processing and unmanned rapid development. With this as a backdrop, the automation of casting parts is promoted. However, defects such as blowholes are often found after machining, which makes the tool easy to be damaged and therefore can not be completely unmanned. In the past, the flaw detection of casting parts mostly used X-ray or γ-ray method, while the research on ultrasonic method was rare. The reason is due to: the probe structure there is insensitive or close-range sound field; surface roughness and produce multiple surface reflection noise interference, internal material such as graphite scattering; attenuation or the resulting S / N decline many questions.