What Is Thermomechanical Treatment?

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Thermomechanical Treatment Influence on the High-speed Steel Hardness and Wear ________________________________________ 1. Introduction In general, most pieces executed for the industry are of the metallic materials, being processed by cutting; therefore the consumption of cutting tools is significant. Although the materials for cutting-tool manufacturing are more and more diversified, their range being in a permanent extension, the old materials have not been utterly abandoned, but their role has only diminished. Nowadays, the tools obtained by physical vapour-deposit methods (PVD) represent more than 50% of the overall cutting tool consumption and are likely to go beyond. Thanks to an acceptable price/quality ratio and to good toughness…show more content…
High temperature thermomechanical treatment (HTTMT) can be used for processing tools and other high-speed steel components of simple geometrical shapes - Dobrzanski[4]. Applying thermomechanical treatments, the resistance properties increase simultaneously maintaining the good values of plasticity, when the deformation degree is between 40-50% - Popescu[5]. If deformation occurs through forging, the resilience has maximal values for a deformation degree of 60-80%. In the case of other high-speed steels, improved characteristics of the hardness, moment-resistance and resilience were obtained, for deformation degrees of 45-85% -…show more content…
Microstructure of plastic deformed HS2-9-1-8 steel:  = 0% (a),  = 50% (b),  = 70% (c) The thermomechanical treatment continued with an oil quenching (oil temperature 100oC), which maintained the positive evolution of the microstructure (Murakami attack reagent, 400 x enlargement). For =70% one observed the carbides with small dimensions (dark colour area) and their uniform distribution. The =70% microstructure is better than =60% and obviously better than =0% (see figure 2). Figure 2.Microstructure of the thermomechanical treatment HS2-9-1-8 steel:  = 60% (a),  = 70% (b) 3. Experimental Results The tests were performed on cylindrical samples of HS2-9-1-8 high-speed steel with the initial diameter of 25 mm and the initial height of 40 mm. These samples were pressed through forging with various deformation degrees. The deformation degree was calculated with (1). Applying HTTMT determines significant improvement of the HS2-9-1-8 high-speed steel micro-structure compared to the samples that have not benefited from plastic deformation. For the thermo-mechanically treated and oil or air quenched samples, the hardness was

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