A heat recovery steam generator (HRSG) is one of the major pieces of equipment in a gas turbine combined cycle power plant that boasts a high thermal efficiency and produces minimal CO2 emissions. An HRSG is a kind of heat exchanger that recovers heat from the exhaust gases of a gas turbine to an extreme degree. The heat is recovered in the form of steam which is served as the power source of a power-generating steam turbine. For the heat-transfer tubes of an HRSG, finned tubes with excellent he