Influence of chemical composition on intergranular corrosion susceptibility of novel Super304H austenitic heat-resistant steel
Influence of chemical composition on intergranular corrosion susceptibility of novel Super304H austenitic heat-resistant steel
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DOI：
10.1179/1743278214y.0000000164
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
Chunlei Zhang;X. Xiong;S. Ping;Yan Gao
中科院分区：
文献类型：
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作者：
Chunlei Zhang;X. Xiong;S. Ping;Yan Gao
为了研究化学成分对Super 304 H钢晶间腐蚀（IGC）性能的影响，采用光谱分析、扫描电镜和H2SO 4-CuSO 4-Cu片溶液浸泡试验等方法，对Super 304 H钢的化学成分和IGC水平进行了分析和评价。结果表明，在所有管中存在四个IGC水平。在碳含量相近或铌含量相近的条件下，IGC磁化率随铌含量或碳含量的增加而随机变化。当C含量大于0.10%时，Super 304 H钢易发生IGC敏感，而几乎所有不具有IGC敏感性的钢管，其Nb含量都接近Nb上限的0.60%。Nb/C质量比对IGC电阻的影响方面，Nb/C质量比小于5·00的试样易发生IGC敏感，Nb/C质量比大于8·15的试样无IGC敏感性，而Nb/C质量比在5·00 ~ 8·15之间的试样IGC水平呈随机波动趋势。在此Nb/C区的一些样品的高磁化率归因于不适当的热处理工艺。
In order to investigate the influence of chemical compositions on the intergranular corrosion (IGC) resistance of the Super304H steel, the chemical compositions and IGC levels of as received Super304H tubes were analysed and evaluated respectively by spectral analysis, scanning electron microscopy and immersion test in H2SO4–CuSO4–Cu chip solution. The results show that there exist four IGC levels in all the tubes. In condition of similar C content or similar Nb content, the IGC susceptibility is revealed to change randomly with the increasing Nb content or C content, respectively. Further more, when C content is more than 0·10%, Super304H steel will be easily sensitised to IGC, while almost all the tubes without IGC susceptibility have Nb content close to 0·60% of upper Nb limit. As to the influence of Nb/C mass ratio on IGC resistance, the sample with Nb/C ratio less than 5·00 will be easily sensitised and the sample with Nb/C ratio more than 8·15 will have no IGC susceptibility, but the IGC levels of tubes with Nb/C ratio between 5·00 and 8·15 incline to fluctuate randomly. The high susceptibility of some samples in this Nb/C region is attributed to the improper heat treatment process.