Effect of phase transformation induced hydrogen desorption on bendability of galvanized advanced high strength steels

• Galvanizing process traps hydrogen in the AHSS. • Hydrogen–induced fisheye fracture governs bend failure of galvanized AHSS. • Hydrogen can be greatly reduced by inducing transformation before galvanizing. • Superior bendability can be achieved with the new phase transformation schedule. The present study investigates the impact of hydrogen desorption induced by phase transformation on the bendability of galvanized Advanced High Strength Steels (AHSS). Hydrogen, absorbed during annealing and trapped inside steel due to the presence of zinc coating, compromised the formability of AHSS. In the present study, two hot-dip galvanized AHSS coils were produced with different phase transformation schedules. Their formability was evaluated using a 90-degree V-bend test. The findings reveal significant differences in bendability, attributed to variations in hydrogen content within the steels. This research aims to propose a production concept that minimizes hydrogen content in hot-dip galvanized AHSS, thereby enhancing bendability. The study highlights the role of phase transformation in mitigating hydrogen embrittlement and improving the local formability of AHSS, providing valuable insights for steelmakers and automotive manufacturers