from the conferences organized by TANGER Ltd.
Mini-thixoforming is a method of processing metals at temperatures between the solidus and liquidus. Thanks to the small volume of feedstock, it allows very rapid heating and solidification rates to be achieved with great accuracy. With these features, it can even be used for processing materials with a very narrow freezing range which are otherwise unsuitable for conventional semi-solid processing techniques. Besides, the mini-thixoforming process can be used with difficult-to-form materials, such as high-alloyed powder steels. In these steels, unconventional microstructures can be produced by semi-solid processing. In the present experiment, powder steels with specific chemistries were used for obtaining such unconventional microstructures. The chemical compositions of these steels were selected with the purpose of exploring the effects of individual alloying elements, namely vanadium, chromium, molybdenum and tungsten. The materials in question were the CPM 15V, CPM S30V, K190 and CPM REX121 steels. Processing parameters were tentatively calculated for all of them. Semi-solid forming trials were then performed based on these calculations. Once the semi-solid processing parameters were verified experimentally, the required mould cavity filling and surface quality of demonstration products were achieved. All mini-thixoformed materials contained austenitic-martensitic matrix with various types of carbides.
Keywords: Mini-thixoforming, semi-solid state, powder steel, CPM 15 V, CPM S 30V© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.