Abstract
Recently, there has been increasing demand for long life of industrial products. High-strength alloy coating on necessary parts can decrease manufacturing costs for prolongation of life. This study proposes a laser surface alloying method to form an Fe-Al alloy coat on carbon steel. A defocused CO2 laser was used to irradiate Al foil on a steel block by shot lining. Mutual diffusion proceeds with laser heating of Al foil, and the Fe-Al alloy grows. For example, Fe3Al grows at ≥950°C. Two laser irradiation methods were used. In low-speed laser scanning, the laser beam scanned along a straight line at 5.0 mm/s. In high-speed laser scanning, the laser beam was reciprocated along a straight line at 100 Hz, and was considered as a linear heat source. The metal structures of the laser-irradiated area were observed. The results indicated that a local Fe-Al alloy coat was formed by high-speed laser scanning without changing the properties of the base material.
