Scholarlink

<p>Above- and below-<i>M</i><sub>s</sub> austempering, and two-step austempering for a low-carbon carbide-free bainite steel were carried out. The microstructure of austempered samples were detected by scanning electron microscopy, electron backscatter diffraction and X-ray diffraction. The tensile properties and instrumented impact toughness were also tested. It was found that compared to the above-<i>M</i><sub>s</sub> austempering, below-<i>M</i><sub>s</sub> austempering and two-step austempering improve the mechanical properties of bainite steel in different aspects. Below-<i>M</i><sub>s</sub> austempering increases the yield strength mainly due to the existence of tempered martensite and improves the impact toughness because of the increase in propagation energy of the crack. In addition, the ductility of bainite steel is increased by two-step austempering due to the increased bainite fraction and more stable retained austenite. Therefore, the best combination of strength and toughness is obtained by below-<i>M</i><sub>s</sub> austempering, while the best combination of strength and elongation is obtained by two-step austempering. Moreover, the relationships between microstructure, tensile properties and impact toughness were analyzed in detail.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Improvement in mechanical properties of low-carbon carbide-free bainite steel by below-Ms austempering and two-step austempering

  • 期刊论文

  • 发表日期：

    2026年5月26日

查看全文
  • Ya-Lin Liang,
  • Ming-Xing Zhou,
  • Xiao-Long Gan,
  • Jun-Yu Tian,
  • Zhen-Ye Chen,
  • Guang Xu

摘要

Above- and below-Ms austempering, and two-step austempering for a low-carbon carbide-free bainite steel were carried out. The microstructure of austempered samples were detected by scanning electron microscopy, electron backscatter diffraction and X-ray diffraction. The tensile properties and instrumented impact toughness were also tested. It was found that compared to the above-Ms austempering, below-Ms austempering and two-step austempering improve the mechanical properties of bainite steel in different aspects. Below-Ms austempering increases the yield strength mainly due to the existence of tempered martensite and improves the impact toughness because of the increase in propagation energy of the crack. In addition, the ductility of bainite steel is increased by two-step austempering due to the increased bainite fraction and more stable retained austenite. Therefore, the best combination of strength and toughness is obtained by below-Ms austempering, while the best combination of strength and elongation is obtained by two-step austempering. Moreover, the relationships between microstructure, tensile properties and impact toughness were analyzed in detail.