Abstract
This study investigates the heat treatment response and microstructure evolution of high-carbon steels for additive manufacturing. Moreover, the role of nitrogen as an interstitial alloying element is addressed. Stainless steel 440C, cold-work D2, hot-work H13, and T15 high-speed tool steel overspray powders from spray forming were investigated. The thermal behavior of these materials was examined using a thermal analyzer that combines calorimetry and thermogravimetry. Additionally, interstitial alloying with nitrogen was performed in-situ to understand its influence on thermal behavior. The (near-)equilibrium nitrogen solubility in 440C and D2 in contact with flowing N2 gas was recorded as a function of temperature through the interval 1200 to 800 °C. The microstructure of the steel powders was characterized by light optical microscopy and X-ray diffraction.
The potential of nitrogen alloying and the importance of optimized heat treatment protocols are emphasized with respect to high-carbon steels in additive manufacturing applications.
