Mechanic, metalurgic and factografic characterization of a composite of microalloyed steel (API X65) cladded with austenitic stainless steel (AISI 308L)

In some offshore structures, pipes with good mechanical resistance and internal surfaces that have also good corrosion resistance are necessary. To associate these properties, one possibility is to make a cladding process in the pipe. To evaluate this kind of composite, a pipe (API X65) was clad with stainless steel (ASTM 308L) by GMAW process and sectioned in several specimens for different analyses. The work starts qualifying the quality of the composite with bending tests. The load that was recorded in this test was the guide to three-point-fatigue tests that gave us the possibility to plot an S-N curve. The tension was the most tensioned point in the specimen. To verify the metallographic conditions of both materials and the interface, metallographic analyses with a transversal cut in the specimens and hardness test across the composite were accomplished. The fatigue tested specimens were submitted to fracture analyses to know how the failure occurs. These analyses contain photos of the specimen's fracture - showing the origin of the failure, a metallographic of the specimen's interface to check undesired microstructures that could cause a failure and micrographs of the most tensioned point of the specimen to check the initial failure mechanism. The results in the following work show a good way of cladding process.