Effect of Ce on inclusion evolution and HAZ mechanical properties of Al-killed high-strength steel

ABSTRACT

The effect of Ce on inclusion evolution behaviour in 700 MPa class Al-killed high-strength steel was investigated through experimental observations and thermodynamic calculations. Simulated welding experiments and mechanical characterisation tests of the heat-affected zone (HAZ) were also carried out to investigate the effect of adding Ce on the welding performance. The results reveal that the typical inclusions of Ce-free steel are the CaS + Mg–Al–O + Ti(C,N) complex inclusion and isolated CaS inclusion. For Ce-containing steel, the typical inclusion is Ce–Ca–O–S + CaS + Ti(C,N). Furthermore, the number density of inclusions increases, and the average size of inclusions decreases after adding Ce. Lastly, the toughness and strength of the HAZ tested with heat inputs of 25 and 50 kJ cm^–1 are evidently improved by adding Ce.

KEYWORDS:

• Cerium oxide metallurgy
• heat-affected zone
• welding performance
• non-metallic inclusions

Acknowledgements

The authors are grateful for the financial support of the National Natural Science Foundation of China (No. 52074026) and the State Key Laboratory of Advanced Metallurgy (Grant No. 41619003 and 41618020). The Science and Technology Project of Inner Mongolia Autonomous Region of China (No. 2020GG0109) is also greatly acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors are grateful for the financial support of the National Natural Science Foundation of China [grant number 52074026] and the State Key Laboratory of Advanced Metallurgy [grant Numbers 41619003 and 41618020]. The Science and Technology Project of Inner Mongolia Autonomous Region of China (grant number 2020GG0109] is also greatly acknowledged.