Austenite Grain Growth and Its Effect on the Mechanical Properties of Super304H Heat-Resistant Steel

作者：Wu, Yue; Liu, Run; Zhan, Xianqiang; Liu, Junjian; Wang, Wanli; Wang, Yan; Tang, Wenming^*

来源：JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, 2023, 32(5): 2228-2236.

DOI：10.1007/s11665-022-07255-9

• abnormal grain growth
• mechanical properties
• pre-deformation
• solution treatment
• Super304H heat-resistant steel
• texture

In this work, Super304H steel samples of uniform, coarse austenite grains are prepared by pre-deformation and subsequent solution treatment. The grain characteristics and effects of their size on the room-temperature and high-temperature mechanical properties of the samples are investigated, and the austenite grain growth mechanism is revealed. The results show that weak textures of < 111 > and < 100 >//RD (rolling direction) exist in the as-supplied Super304H steel samples. After pre-straining of no more than 6% and subsequent solution treatment, the austenite grains grow rapidly. Meanwhile, there are two textures in the < 111 > and < 100 >//RD directions in the samples in which the < 111 >//RD texture is more intensive. The deformation among neighboring austenite grains is inhomogeneous, wherein strain energy differences are generated as the driving force for abnormal austenite grain growth, which follows the faceting grain boundary mechanism. As grain size increases, the room-temperature and high-temperature tensile yield strength (R-p0.2) and elongation at fracture of the Super304H steel samples monotonously decrease. When the grain size reaches 41 mu m or greater, the R-p0.2 of the samples cannot meet the operating requirements of a Super304H steel tube any longer.

• 单位
  TEST; test