The formation mechanism of a friction-surfaced (FSed) coating of super austenitic stainless steel AISI 904 L with high stacking fault energy was investigated with a stop-action method. The advancing side, center and retreating side of the surfaces and cross-sections of the coating and the bump were studied in detail using EBSD. The microstructure of the bump formed at the end was found to be different from that of the FSed coating. A systematic analysis of the microstructure revealed the formation mechanism of the coatings. A two-step formation mechanism of the FSed coating was proposed.