Mechanical Properties of Additively Manufactured 17-4PH SS: Heat Treatment

The effects of the thermal post-treatments on the mechanical properties of SLMed 17-4PH stainless steel are studied. Three thermal post-treatments are carried out: (E0) as received state, (E1 and E2) solution annealing treatment and (E3) aging treatment. Microhardness, impact-strength, and wear tests are carried out to determine the effect of treatment on the mechanical properties of SLMed 17-4PH. The results showed that the hardness of 17-4PH at the E0 state is a greater than the hardness of the powder. This hardness decreases slightly from 418 HV to 384 HV after the solution annealing treatment E2 and increase again after E3 ageing treatment to around 447HV. A hardness difference between the two manufacturing directions was also observed. This difference almost disappears after the E3 ageing treatment. The impact strength results show a huge drop in impact strength for 17-4PH obtained by SLM. An improvement in wear behaviour following heat treatment, especially in the case of ageing.