Structure Formation Features of Corrosion-Resistant Powder Material Type 316L Gas-Flame Sprayed Coating

Abstract

Implementation of the extensive possibilities of the gas-flame spraying technique with respect to the main advantages of the powder metallurgy is only possible with a methodologically justified approach to materials selection, a study of gas-dynamic processes taking place in equipment during coating formation (powder flow rate, temperature and fl ame type, etc.), and control of metallurgical processes (structure formation, liquation, phase transitions, etc.). Such phenomena need to be controlled both at the stage of initial wire and powder production, and during coating deposition. In practice, the choice of coating materials for the oil and gas industry (such as pipes, distillation columns, pumping units), should not solely be based on powder chemical composition. Features of coating structure are typically not taken into account, which are interrelated both with the initial powder or wire formation technique, and with coating deposition process parameters. This work demonstrates the differences in structure formation within steels and gasflame coatings of the similar alloy composition. A direct relationship of structure formation in gas-flame coatings is established not only with deposition technology, but mostly the method of forming the initial powder material structure. It is shown that for the effective application of coating material it is necessary to determine the alloy system, the structural class and formation technology of the powder material connected with possible inheritance and/or structure-phase transformations during coating deposition.