Inconel 625 Performance as Hyperbaric GMA Welding Consumable for Diverless Retrofit Tee Hot Tap Applications

The use of fully remotely installed retrofit tees for hot tapping applications is an extremely attractive economic option for maximising the potential of oil-fields.  A diverless hot tap tee system is in the process of being built and commissioned, with hyperbaric GMA welding selected as the internal saddle seal welding method.  Process capability has previously been demonstrated in the 145 to 1,000m range using a specially-developed 1.0mm metal-cored wire.  This paper considers the performance and application of a 0.9mm Inconel 625 wire for hot tap welding.  A direct comparison of the performance of the two wires is made: process and electrical stability; metallurgical analysis; and, macro quality and mechanical properties.