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早在70年代,西德就研制、出售用于分选混料的各种电磁分选仪(?)而当时我国无损检测研究和应用大多数侧重于金属件的探伤。80年代以来,哈尔滨科技大学万国庆等先后研制出几种采用初始磁导率法或结合剩磁法进行钢铁件物理和机械性能无损检测的设备。90年代推出的新一代SGF-ⅡW分选仪是这种设备的典型代表。该设备既能用数字直接显示被测钢铁件硬度,又能用微安表显示,可用于钢铁混料分选、钢号鉴别和热处理质量检测等。在钢铁件硬度分选方面已积累了许多成功的经验,如80年代初用GCJ型仪对KTH330 08可锻铸铁管件进行了硬度的无损测试。由于初始磁导率与材料的诸多因素有关,而可锻铸铁件由于热处理工艺复杂,有时会出现几种不同的组织,因此仪器显示值和实际硬度之间可能会出现非线性或多值现象,因此如何应用SGF-ⅡW仪并结合其它手段和专业知识正确判断分选结果,提出超差可锻铸铁件成因和处理意见,以提高生产效率和减少废品率是亟需解决的问题。本文通过实例对上述问题进行探讨。
As early as the 1970s, West Germany developed and sold a variety of electromagnetic separators (?) For sorting mixed materials. At that time, most of the research and applications of nondestructive testing in China focused on the detection of metal parts. Since the 1980s, Wan Guoqing, Harbin University of Science and Technology has developed several kinds of equipment using initial permeability method or the combination of remanence method for nondestructive testing of the physical and mechanical properties of steel parts. The new generation SGF-IIW sorting machine introduced in the 90’s is the typical representative of this kind of equipment. The device can not only display the hardness of the tested steel piece directly by digital but also display on the microampere meter. It can be used for the sorting of steel and iron, steel identification and heat treatment quality inspection. Many successful experiences have been accumulated in the hardness sorting of steel parts, such as the nondestructive testing of the hardness of KTH330 08 malleable cast iron pipe fittings by GCJ type in the early 1980s. Since the initial permeability depends on many factors of the material, the malleable cast iron sometimes has several different structures due to the complicated heat treatment process, so there may be non-linear or multi-value phenomena between the displayed value and the actual hardness of the instrument. Therefore, how Application of SGF-ⅡW instrument combined with other means and expertise to correctly determine the sorting results, put forward the reasons for ultra-malleable cast iron pieces and processing advice to improve production efficiency and reduce the rejection rate is an urgent need to be addressed. This article discusses the above issues through examples.