Effect of on-line solution treatment on the microstructure and mechanical properties of 2507 duplex stainless steels
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摘要: 利用热轧试验机组、Zeiss光学金相显微镜及透射电子显微镜(TEM)研究了在线固溶处理工艺及轧后待温时间对其组织和性能的影响。结果表明,在线固溶处理与离线固溶处理相比铁素体含量更高,屈服强度和抗拉强度较高,塑性和低温韧性降低较为明显,随着轧后待温时间的增加,锯齿状奥氏体含量逐渐降低,并最终转变为岛状奥氏体。TEM分析表明,在线固溶处理的铁素体相内分布大量位错。随着待温时间增加,铁素体和奥氏体的相界处有Cr2N相析出,造成钢板的塑性和耐蚀性能降低,考虑到脆性相析出数量及奥氏体形态演变,轧后钢板应快速入水。Abstract: Effects of on-line solution treatment and holding time on the microstructure and mechanical properties of 2507 duplex stainless steels were studied by hot-rolling experiments, Zeiss optical microscope (OM) and transmission electron microscopy (TEM). The results show that the volume fraction of ferrite, yield strength and tensile strength of the on-line solution treated steels are slightly higher than those of the off-line aging specimens, while the elongation and low temperature impact toughness are obviously decreased. With increasing the holding time after rolling, the amount of zigzag austenite at phase boundaries decreases and changes to island austenite eventually. TEM analysis shows that a large number of dislocations are distributed in the ferrite phases by on-line solution treatment. With increasing the holding time, the Cr2N particles precipitate at the phase boundaries between ferrite and austenite, which lead to the reduction of the ductility and corrosion resistance. Considering the amount of brittle phase and the evolution of austenite morphology, the steel plates should be quickly immersed in the cooling system after rolling.
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Key words:
- 2507 duplex stainless steel /
- ductility /
- solution treatment /
- microstructure /
- Cr2N precipitates
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表 1 不同工艺下2507双相不锈钢的力学性能
Table 1. Mechanical properties of 2507 steels produced by different technical methods
工艺 σ0.2/MPa σb/MPa 延伸率/% −20 ℃冲击功/J 在线处理 606 842 28.4 161 离线处理 581 812 33.4 183 -
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