In this paper the different metal transfer modes of a hot-wire GTAW process with indirect resistive heating are presented. The hot-wire GTAW process is characterized by an upstream preheating unit that is used to heat the wire before it reaches the melt pool. Thus, the contact between the melt pool and the heated wire is not necessary.
In order to examine the metal transfer of the wire, deposition welds are analysed using a high-speed camera with a laser light source as wells as a data acquisition unit. The presented results comprise the impact analysis of the GTAW current, hot-wire current, wire-feeding rate, inclination angles of the wire-feed as well as the travel direction.
The observed metal transfer modes can be characterised as either a re-occurring melting bridge, or the solid wire touching the meltpool. The investigations also show that the occurring transfer mode depends mainly on the GTAW current and the hot-wire current.