Fig. 1. SEM image of hydrogen resistant steel HR-2 powders

Fig. 2. Schematic of printing strategy of hydrogen resistant steel HR-2 and sampling of sliced samples

Fig. 3. Tensile specimen size

Fig. 4. Macro morphology of formed samples

Fig. 5. Defect morphology

Fig. 6. Experimental results. (a) Total number of pores varies with energy density; (b) maximum pore area varies with energy density;(c) relative density varies with energy density(metallography); (d) density varies with energy density (Archi-medes)

Fig. 7. Microstructures. (a) (b) Group 1; (c) (d) group 2; (e) (f) group 3; (g) (h) group 4; (i) enlarged view of area A in Fig.(h);(j) enlarged view of area B in Fig.(h)

Fig. 8. EBSD patterns. (a) (b) Group 1; (c) (d) group 2; (e) (f) group 3; (g) (h) group 4

Fig. 9. Grain size distribution. (a) (b)Group 1; (c) (d) group 2; (e) (f) group 3; (g) (h) group 4

Fig. 10. Schematic of lap joint of molten pools with different energy densities

Fig. 11. Experimental results. (a) Hardness of XY and XZ surfaces varies with energy density; (b) tensile engineering stress-strain curves of HR-2 stainless steel fabricated by SLM; (c) change of tensile strength R_m and yield strength R_p0.2 with energy density;(d) change of elongation A and section shrinkage Z of sample with energy density

Fig. 12. SEM images of fracture morphology of samples. Low magnification images of (a) group 1, (c) group 2, (e) group 3, and (g) group 4; high magnification images of (b) group 1, (d) group 2, (f) group 3, and (h) group 4

Table 1. Experimental process parameters of hydrogen resistant steel HR-2 stainless steel

Table 2. Standard for tensile properties of hydrogen resistant steel HR-2