PSI - Issue 24

Jacopo De Nisi et al. / Procedia Structural Integrity 24 (2019) 541–558

550 10

Paolo Folgarait et al./ Structural Integrity Procedia 00 (2019) 000 – 000

deviation, calculated for each group as per Table 2 . For all the groups (except for 0 group) 2σ is much lower than 0,5% of actual value, a typical measurement uncertainty in HV hardness tests. No reference is in ASTM A564/A564M Standard for HV hardness.

Table 7 . HV1 hardness indentation tests after heat treatment conditions performed on L-PBF 15-5 specimen. Position Group 0 Group A1 Group A2 Group B1 Group B2 Group C A 384,5 437,3 433,3 472,3 451,8 355,0 B 370,5 450,8 436,3 460,8 425,2 364,7 C 374,5 442,2 435,2 453,8 429,0 357,2 D 367,7 426,2 441,5 463,7 427,2 364,3 E 371,3 439,5 442,0 459,3 429,5 352,3 F 391,5 433,3 443,5 454,8 428,0 371,0 G 365,8 459,0 432,7 464,5 445,2 362,3 H 364,8 459,3 429,2 459,2 431,5 372,3 I 375,8 439,2 433,5 473,8 440,0 358,8 average HV1 374,1 443,0 436,4 462,5 434,1 362,0 st. dev. 15,17 19,07 9,37 14,37 15,37 12,66 st. dev./average [%] 4,05 4,30 2,15 3,11 3,54 3,50 Requirements ASTMA564/A564M * * * * * * * No reference for HV hardness indentation tests.

Fig. 4 . HV indentation tests performed on specimen group 0 to C, position 1 to 9 (namely position A to I, as per Fig. 2).