This paper discusses various types of steels, including high strength steels and fine grain structural steels for offshore drilling application. Continuous cooling diagrams are used to explain the requirements for the welding process, as the desired mechanical properties must be achieved through controlled effects on the microstructure. A variety of wires may be used, such as solid, folded flux cored, seamless flux cored, and metal cored wires. After balancing the pros and cons of these different types, conclusions for the use of seamless flux-cored wires are drawn for special applications. A description of the manufacturing process for seamless flux cored welding wires is given. The different properties and applications of the three main types of seamless flux cored wires are explained, namely basic, rutile and metal-cored wires. The necessary welding requirements and parameters for optimizing the welding seam quality with respect to good strength and ductility are presented, including the role of welding process, thickness of the component, and seam shape. Also, the connection between the chemical composition and t8/5-cooling time on cold-cracking resistance is explained, as well as the effect of stick-out and pre-heating on hydrogen and nitrogen content. Examples will illustrate the application of seamless flux cored wires for offshore exploration.
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