Borkovcová Klára, Novák Pavel, Merghem Nawel, Tsepeleva Alisa, Salvetr Pavel, Brázda Michal, Rajnovic Dragan
Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
Comtes FHT a.s., Průmyslová 995, 334 41 Dobrany, Czech Republic.
Materials (Basel). 2023 Jun 30;16(13):4760. doi: 10.3390/ma16134760.
Niobium is recently considered one of the potential alloying elements for tool steels due to the formation of hard and stable carbides of MC type. Its use is limited by the fact that these carbides tend to coarsen during conventional melting metallurgy processing. This work explores the potential of additive manufacturing for processing Nb-alloyed tool steel with a high content of carbon. Directed energy deposition was used as the processing method. It was found that this method allowed us to obtain a microstructure very similar to that obtained after the use of consolidation via spark plasma sintering when subsequent heat treatment by soft annealing, austenitizing, oil quenching and triple tempering for secondary hardness was applied. Moreover, the soft annealing process could be skipped without affecting the structure and properties when machining would not be required. The hardness of the steel was even higher after additive manufacturing was used (approx. 800-830 HV 30) than after spark plasma sintering (approx. 720-750 HV 30). The wear resistance of the materials processed by both routes was almost comparable, reaching 5-7 × 10 mmNm depending on the heat treatment.
由于能形成MC型硬质稳定碳化物，铌最近被认为是工具钢潜在的合金元素之一。其应用受到限制，因为在传统熔铸冶金加工过程中，这些碳化物容易粗化。本研究探索了增材制造用于加工高碳铌合金工具钢的潜力。采用定向能量沉积作为加工方法。研究发现，当随后进行软退火、奥氏体化、油淬和三次回火以获得二次硬度的热处理时，该方法能使我们获得与通过火花等离子烧结固结后得到的微观结构非常相似的结构。此外，若不需要进行机械加工，软退火过程可以省略而不影响组织和性能。使用增材制造后钢的硬度（约800 - 830 HV 30）甚至高于火花等离子烧结后的硬度（约720 - 750 HV 30）。两种加工路线所加工材料的耐磨性几乎相当，根据热处理情况，磨损量达到5 - 7×10 mmNm。
