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The influence of hatch spacing on tensile properties of high deposition rate gas metal arc-directed energy deposition of 316L and 316LSi was explored 

Abstract Gas metal arc directed energy deposition (GMA-DED) has potential for the power generation industry to reduce both time and cost since larger and more complex part geometries can be constructed compared to the typical subtractive methods. The performance of GMA-DED builds can be influenced by the deposition method, resulting microstructure, and formation of defects or secondary phases in the final component. Previous work in the literature evaluated the mechanical properties of GMA-DED builds for a range of austenitic stainless steels, however there is limited data on the high temperature mechanical behavior. This work evaluated the high temperature creep properties of GMA-DED builds constructed with type 316H, 316L, 316LSi, and 16-8-2 stainless steels at 650 °C, 750 °C and 825 °C. The alloy with longest time to rupture for a given stress varied depending on test temperature. Creep damage accumulation at grain boundaries was observed along with grain boundary precipitates which likely aided in damage accumulation. Evaluating the creep properties with the Larson-Miller parameter showed the majority of results fell within the scatter band of creep performance for wrought 316 alloys, indicating the GMA-DED process may be suitable for use in advanced energy systems. 

Abstract Temper bead (TB) welding is often used as an alternative to post weld heat treatment (PWHT) for repair of pressure vessels and piping in the nuclear power industry. Historically, qualification of TB welding procedures has employed the Charpy V-notch test to ensure acceptable heat-affected-zone (HAZ) impact properties. The 2004 Edition of ASME Section IX provided a new provision in QW-290 that allows temper bead qualification using a peak hardness criterion. The peak hardness provision is appropriate for industries such as oil and gas, where peak allowable hardness is specified to ensure adequate resistance to sulfide stress cracking in sour service environments. However, a peak hardness criterion is not appropriate where impact properties are specified for resistance to brittle fracture during low temperature conditions that can occur during certain postulated accident scenarios at a nuclear power plant. Work at the Electric Power Research Institute (EPRI) and The Ohio State University (OSU) show that a hardness drop protocol can be used to demonstrate acceptable impact properties in the HAZ of a temper bead weld. This paper presents a quantitative correlation between hardness measurements and HAZ microstructures with presumed optimum impact properties using a hardness drop approach. The overarching goal is to develop a hardness test protocol for temper bead weld procedure qualification for applications where impact properties are specified.