Study on the microstructure and mechanical properties of explosive welded 2205/X65 bimetallic sheet

• 2205/X65 bimetallic plate was produced by explosive welding.
• Microstructural inhomogeneity of 2205/X65 bimetallic sheet was investigated.
• Mechanical inhomogeneity of 2205/X65 bimetallic sheet was studied.
• Distribution of alloy elements across 2205/X65 interface was studied.
• Weak positions of 2205/X65 sheet in bending process were revealed.

In this study, microstructural inhomogeneity and mechanical properties of explosive welded 2205 stainless steel/X65 pipe steel bimetallic sheets were investigated. The explosion-bonded 2205/X65 bimetallic sheets had good shear strength. The tensile shear fracture primarily occurred in the interior of X65 material and primarily exhibited dimple morphology. Fine crystal grains in the 0.5–2 μm range were found all over the narrow localized melted zone near the 2205/X65 interface, whereas a coarse columnar crystal structure growing along the perpendicular direction to the interface formed in the wider localized melted zone. Quasi-cleavage fracture morphology was observed in the coarse columnar crystal region after the stratified tensile test. The junction of the three regions near the interface with large differences in morphology was the weak point in the bimetallic sheet, where Y-shaped cracking easily occurred under a loading force. Stratified tensile test and micro-hardness tests for the explosively welded bimetallic sheet showed that severe hardening occurred in the 2205 cladding, and the most severe metal hardening occurred near the interface. Tests for 45° face bending and root bending tests were conducted under extreme conditions. The results showed that voids were prone to appeared in the peninsula and island morphologies near the interface.