Study on the Sintering Behavior and Microstructure Development of the Powder Injection Molded T42 High-speed Steel

초록

HSS has high strength, wear resistance, and hardness together with an appreciable toughness and fatigue resistance. PIM has received attention owing to its ability to shape without additional processes. The experimental specimens were manufactured using PIM with T42 powders (59 vol.%) and polymer (41 vol.%). The green parts were solvent debound in n-Hexane at 60 degrees C for 24 hours and further thermally debound in a N-2-H-2 mixed gas atmosphere for 18 hours. The specimens were then sintered in a vacuum (10(-5) mtorr), hydrogen and nitrogen gas atmosphere. In the vacuum, the specimen sintered at 1240 degrees C had the highest hardness at 520 Hv. In this condition, the carbides were well-distributed and located in the grain. The grain size was 10 mu m, and the carbide size was 1 mu m. When sintering in a vacuum at over 1260 degrees C, the carbides converted to eutectic carbide and were located at the grain boundary. Grain growth was observed. The specimens sintered in a nitrogen atmosphere had a lower density and hardness than that produced in the vacuum.

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