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.

摘要

通过实验观察和热力学计算，研究了Ce对700 MPa级Al镇静高强度钢中夹杂物演变行为的影响。还进行了热影响区（HAZ）的模拟焊接实验和力学性能测试，以研究添加Ce对焊接性能的影响。结果表明，不含Ce的钢的典型夹杂物为CaS + Mg–Al–O + Ti（C，N）复合夹杂物和孤立的CaS夹杂物。对于含Ce的钢，典型的夹杂物是Ce–Ca–O–S + CaS + Ti（C，N）。此外，添加Ce后，夹杂物的数量密度增加，并且夹杂物的平​​均尺寸减小。最后，在25和50 kJ cm ^–1的热量输入下测试的热影响区的韧性和强度 添加铈明显改善了Ce。