Evaluation of Structure, Phase Composition, and Operating Properties of Coatings Made by Laser Surfacing. Part 2*

Abstract

Questions are considered of reaction of an offshore oil and gas structure (OOGS) base with a stream of sand or other bottom deposits, which cause hydroabrasive wear of metal and concrete parts of underwater zone structures. A test procedure is developed for corrosion and mechanical wear with surface friction of test specimens in a mass of loose abrasive moistened with corrosive marine medium in order to evaluate the life of materials used for strengthening these OOGS zones. Tests are performed on multilayer coatings prepared by laser surfacing. Surfacing layer microhardness, structure, phase composition, and wear rate are evaluated during tests.Oil and gas industry structures of the northern sea shelf are unique marine hydraulic engineering structures within which under open shore conditions considerable loads operate: wave, ice, wind, corrosion, temperature, etc. Depending on climatic conditions, the level and magnitude of loads may vary [1].In designing metal pile-supported and caisson bases of offshore oil and gas structures (OOGS) in order to evaluate the proposed service life, it is necessary to consider many factors, including rates of corrosion, wear with movement of ice masses, and mechanical loads. Life is normally considered as applied to a specific zone characterized by a collection of different actions determining structure surface layer breakdown [2]. Among these zones the following may be separated: atmospheric, splashed, alternating wetting, total immersion, and submersion in bottom ground.Bottom ground may have different strength properties within a region of OOGS location. Depending on the form of ground, the degree of its wearing action on the lower parts of supporting structures may differ markedly. Corrosion fatigue, corrosive-erosion, and cavitation may develop in the area of immersion in bottom ground.With unbonded rocks, it is necessary to consider these with respect to pump dynamics. Reaction of an OOGS base with a stream of sand or other solid bottom deposits may cause hydroabrasive wear of metal and concrete parts of the underwater areas of a structure. The following properties are determined for unbonded deposits: drawing pump flow rate; suspen-