TEM observation and fracture morphology in the CGHAZ of a new 0Cr18Mo2Ti ferritic stainless steel

Bulletin of materials science

Zhang Yonglan¹  Sun Bin¹  Li Yajiang¹  Wang Juan¹ 

[1] Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan 250061, P.R. China$$Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan 250061, P.R. ChinaKey Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan 250061, P.R. China$$

关键词: Ferritic stainless steel;    electron microscopy;    microstructure;    fracture;    heat-affected zone.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

Microstructure, precipitates and fracture morphology in the coarse grained heat-affected zone (CGHAZ) of a new high-purity 0Cr18Mo2Ti ferritic stainless steel were studied by means of optical metallography, SEM, TEM, X-ray diffractometer, etc. Experimental results indicated that grain coarsening resulted in brittle fracture in the CGHAZ of 0Cr18Mo2Ti steel. The reduction of impact toughness in the CGHAZ due to change of cooling rate can be attributed to the increase of nitrides (TiN, Cr₂N, etc). These nitrides in the CGHAZ promote initiation and propagation of brittle cracks. The precipitated Cr₂N nitrides in the grain boundaries decrease impact toughness in the CGHAZ of 0Cr18Mo2Ti steel by promoting crack initiation. In practical applications, the welding heat input (𝐸) should be as low as possible to prevent toughness reduction in the CGHAZ.

【 授权许可】

Unknown