PSI - Issue 14

Anigani Sudarshan Reddy et al. / Procedia Structural Integrity 14 (2019) 449–466 Author name / Structural Integrity Procedia 00 (2018) 000–000

453

5

Table 3: Range of process parameters used for building DMLS samples

Process parameter

Range

Laser power (W)

250-300

Scan speed (mm/sec)

800-1000

Hatch distance (mm)

80-120

Layer thickness (µm)

20-80

Laser spot diameter (µm)

80

Fig. 1. Photographs showing typical samples used in this study for small scale testing, (a) Monolithic DMLS sample (b) Hybrid sample –DMLS SS316L on X20Cr13 (c) Hybrid sample- DMLS CoCrMo welded on FSX414 (d) Cylindrical DMLS sample

Table 4: Heat Treatment cycles used for DMLS and Hybrid samples

S.No

Material

Heat treatment cycle

Solution annealing at 1065ºC in vacuum for 1hour followed by air cooling. Aging heat treatment at 760ºC for 10 hours and furnace cooling for 620ºC in 2 hours and hold at 620ºC for 8 hour followed by air cooling.

1

Monolithic DMLS IN718

1150ºC in vacuum for 4 hours followed by argon gas quenching. 490ºC for 6 hours followed by furnace cooling. 800ºC in vacuum for 4 hours followed by inert atmosphere cooling. 1150ºC in vacuum for 4 hours followed by argon gas quenching.

2

Monolithic DMLS CoCrMo

3

Monolithic DMLS Maraging steel

4

Monolithic DMLS Ti6Al4V

5

Hybrid (CoCrMo on FSX-414)

650ºC for 2 hours 30 minutes followed by air cooling.

6

Hybrid (SS316L on X20Cr13)