Fatigue life analysis of hot forming dies produced by the L-PBF and WA-DED additive technologies

Abstract

Abstract. Additive manufacturing (AM) technologies are widely used for the production of individual complex precise parts and small-scale production. AM has been used in many applications for the manufacturing of sheet metal forming dies. The production of hot bulk forming dies by additive manufacturing technology has not been extensively studied in the literature. Traditional hot working steels exhibit many problems during the AM process, such as crack formation due to complex thermal processing cycles. Maraging/precipitation-hardened (PH) steels may be a good alternative because of their ability to undergo additive manufacturing. One of the main causes of hot forming die failures is thermomechanical fatigue. The fatigue performance of 17-4PH was investigated primarily during high-cycle fatigue (HCF) and low-cycle fatigue (LCF) modes without heat treatment as well as with H1100 heat treatment. The LCF of dies with the heat treatment designation H900, which is most appropriate for die production, has not been intensively investigated. In this work, the mechanical properties and fatigue life of 17-4PH precipitation-hardened steel produced by laser powder bed fusion (L-PBF) and wire arc direct energy deposition (WA-DED) additive technologies were experimentally investigated, and numerical models for high-temperature low cycle fatigue life were developed for 17-4PH steel. Based on the FEM simulation in the commercial program QForm UK, the fatigue life of the produced dies was predicted.