Abstract
Duplex stainless steels are often used in the maritime, nuclear, oil and gas, and process industries due to their combination of acceptable price, good corrosion resistance, high strength and good toughness. This paper uses additive manufacturing to build a bolt geometry with 2205 duplex and characterizes the material performance through Charpy impact toughness testing at -46 °C, tensile testing, x-ray tomography and microstructure examination using light optical and scanning electron microscopy. Two different deposition paths were compared, where one produced high-quality material, while the other produced both systematic lack of fusion and a higher porosity density. X-ray tomography was unable to detect lack of fusion. Both deposition paths satisfied typical requirements for mechanical properties. Solution annealing was necessary to produce acceptable Charpy impact toughness, and tensile properties were acceptable and comparable to those of forged bar material. A repeating pattern of sigma phase precipitation was observed in the as-built material, but the amount was limited and located close to the bolt edge, so it was removed by specimen machining. Despite being able to produce the bolt with additive manufacturing, this will not be implemented in the part production process since its cost was 6.6x higher than an equivalent bolt turned from bar stock.