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MIM 420 martensitic stainless steel
A microstructural investigation of 420 martensitic stainless steel processed by MIM Type 420 martensitic stainless steel covers a wide carbon range of 0.15% to 0.45%. Demand for this material from the 3C, automotive, biomedical and aerospace industries has been increasing thanks to its combination of moderate corrosion resistance, high hardness, and good tensile properties. In this study, Shu-Hsu Hsieh, Dr Chung-Huei Chueh, and I-Shiuan Chen, from Chenming Electronic Technology Corp. (UNEEC), Taiwan, investigated Nb-alloyed 420 produced using BASF SE's Catamold 420 W feedstock. Decarburisation was examined in samples processed in both a graphite furnace and a molybdenum lined furnace. Microstructure, phase and hardness variations from the sintered state to each specific stage in heat treatment were also explored. Additionally, the influence of niobium on the formation of intergranular compounds, carbides, and carbonitrides was also assessed in each heat treatment stage for comparison.
Among the most exciting emerging developments in the modern 3C (computer, communication and consumer-electronics) industry are applications based on advanced metallic materials. These new applications take advantage of materials with excellent mechanical strength combined with reasonably high corrosion resistance, wear resistance and specific magnetic properties, such as ferromagnetism or paramagnetism, depending on the product design and function. These materials include stainless steels and cobalt alloys, as well as other cutting-edge alloys. Some well-known examples for these advanced alloys are camera components (switches and buttons), laptop and smartphone hinges, cases for wearable devices, soft magnetic applications, electronic packaging, heat sinks/heat spreaders for cooling electronics, and USB connectors. A high degree of skill and precision engineering is needed to create the components that go into such devices and there are many hurdles to overcome. It is, however, important that
Vol. 15 No. 4 © 2021 Inovar Communications Ltd
product designers in this field are able to find and select the proper materials quickly and easily in order to keep on top of the fast-paced development. Stainless steels, a group of advanced ferrous alloys, were invented at the beginning of the 20th century in Germany (Eduard
Maurer and Benno Strauss in 1912) and in England (Harry Brearley in 1913). In accordance with the European standard EN 10088, steel is classed as stainless when its chemical composition has a minimum chromium content of 10.5%, which enables the formation of a thin, tenacious, and protective chromium oxide
Fig. 1 Sintering furnaces at Chenming Electronic Technology Corp. (UNEEC), a Taiwan-based global OEM/ODM and a major MIM component producer with operations in Dongguan, China, since 2002
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