Effects of heat treatment on the microstructure and metallurgical properties of the explosively bonded 304 stainless steel—CK45 steel

In this research, the effects of heat treatment are studied on the microstructure and mechanical properties of the explosive bonding of 304 stainless steel plates and CK45 carbon steel with a constant explosive load and various standoff distances. The samples are heat treated in a furnace for 2-h and 4-h at 250℃ and 350℃. The results imply that by increasing the standoff distance from 4 to 5 mm, the impact kinetic energy increases and severe plastic deformation occurs in the bonding interface. The metallography results indicate the wave-vortex nature of the interface with the increase of standoff distance. In addition, heat treatment for 2 h at 350℃ leads to an increase in the thicknesses of intermetallic compounds in the interface. Also, the hardness decreases from 271 to 171 Vickers, and from 279 to 195 Vickers with 2 h of heat treatment at 350℃ in samples with standoff distances of 4 and 5 mm, respectively. Furthermore, the strengths of the samples decrease from 449 to 371 MPa, and from 510 to 433 MPa, respectively. Hardness and strength changes occur due to changes in the thickness of the intermetallic area and an increase in grain sizes.