Effect of pressure and deep cryotreatment on strength of diffusion bonds of St37–1.2542 dissimilar steels

Abstract

The efficiency of welded metals depends on the weld metal’s quality to achieve its useful life. The ability of the weld metal to meet the abovementioned requirements is determined by its physical and mechanical properties. In the present study, eight pairs of specimens were used in four groups for diffusion bonding of St37 to 1.2542 steels such that diffusion bonding was performed on two groups without pressure and two groups with pressure (2 MPa). Then, the groups alternatively underwent deep cryotreatment (DCT) for 10 h; finally, all the groups were tempered at 150 °C for 1 h. The results obtained indicate that, under the non-pressure conditions, DCT had no significant effect on the bond’s strength, while under pressure conditions, the DCT led to a 59% decrease in the bond strength from 15.1 to 6.2 MPa. In addition, in the absence of DCT, applying pressure during the bonding process increased the strength of the bond from 12.0 to 15.1 MPa (25.8%), the reason for which is attributed to an increase in the length of the bond from 160 to 220 μm.