The Scatter in Fracture Toughness of Two Different Pearlitic Railway Wheels

作者：Chen, Runnong; Li, Zhaodong^*; Zhao, Xinlong; Zhou, Shitong; Wang, Xin; Da, Guangjie; Zhang, Xiaofeng; Zhang, Qifu; Li, Xiaogang

来源：JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, 2022, 31(11): 9209-9219.

DOI：10.1007/s11665-022-06903-4

• fracture toughness
• microstructure parameters
• non-metallic inclusions
• pearlitic steel
• statistical scatter
• tessellated stress

This paper focuses on the effect of microstructural aspects on the statistical scatter of fracture toughness of two different pearlitic railway wheels. The microstructure and inclusions of compact tension specimens with the largest differences in fracture toughness of each wheel were quantified; it was found that the inhomogeneous distribution of the type, quantity, and size of inclusions deteriorated toughness to varying degrees, resulting in the scatter in fracture toughness. The tessellated stress of inclusions was calculated according to Brooksbank and Andrews's model. The diameter ratio of composite MnS-oxide to inner wrapped oxides in both wheels is more than 1.28 and without tessellated stress. The maximum tessellated stress generated by oxides of different quantities and sizes is equal, but the range of the stress field is positively related to its size and quantity. The mechanism of different inclusions affecting the fracture toughness scattering was discussed in combination with the fracture process. All three kinds of inclusions can promote ductile fracture through microvoid coalescence, and oxide can also indirectly induce cleavage crack and promote cleavage crack propagation through generating tessellated stress. The mechanism of oxide inclusions that do not directly induce cleavage cracks initiation is proposed.

• 单位
  nanchang hangkong university; University of Science and Technology Beijing