Fig. 1. Pipeline steel with coating

Fig. 2. Samples after coating removal. (a) Sample A; (b) sample B

Fig. 3. Optical micrographs of cleaned surface of sample A

Fig. 4. Element profile on the surface of sample A

Fig. 5. Surface macroscopic morphology of sample A

Fig. 6. Three-dimensional surface morphology of samples after coating removal. (a) Sample A; (b) sample B

Fig. 7. Surface microstructures of sample A. (a) ×1000; (b) ×2000; (c) ×5000

Fig. 8. Surface microstructures of sample B. (a) ×1000; (b) ×2000; (c) ×5000

Fig. 9. Cross-sectional hardness of samples.(a) Sample A; (b) sample B