Correlation between microstructure and impact toughness of weld heat-affected zone in 5 wt.％ manganese steels

作者：Jun-hui Li; Hong-hong Wang; Qiang Luo; Li Li; Chao Sun; R.D.K. Misra

来源：钢铁研究学报(英文版), 2019, 26(7): 761-770.

• 5 wt.％ manganese steel
• Welding heat-affected zone
• Retained austenite
• Tempered martensite
• Impact toughness

The microstructure in welding heat-affected zones of 5 wt.％ manganese steels was studied, and its effect on impact toughness was analyzed. The simulated coarse-grained heat-affected zone (CGHAZ) had the lowest impact toughness of～39 J at-40 ?C because of coarse-grained structure and least volume fraction of retained austenite (RA) of 1.2 vol.％. The impact toughness of simulated intercritical heat-affected zone (ICHAZ) and fine-grained heat-affected zone (FGHAZ) were～165 and～45 J, respectively, at-40 ?C. The effective grain size of simulated FGHAZ was smaller than that of the simulated ICHAZ. Furthermore, microstructural investigation revealed that the simulated FGHAZ and ICHAZ had similarity in volume fraction and stability of RA. However, tempered martensite was present in ICHAZ and absent in FGHAZ. It is proposed that the presence of tempered martensite contributed to good impact toughness in simulated ICHAZ.

• 单位
  University of Texas; 武汉科技大学; The University of Texas