Abstract
Austenite grain growth behavior and its effects on fracture splitting performance for the steel 36MnVS4 connecting rod are investigated comprehensively by fracture morphology and microstructure analysis. The results show that the fine prior austenite grain causes the unilateral spalling fracture surfaces at the big end bore of the waster connecting rod product. Besides, the austenite grain coarsening temperature with a holding time of 1 h is 1000 °C. The austenite grain coarsening time is 4 h at a temperature of 1200 °C and decreases with the increase of heating temperature. The relationship between austenite grain size and holding time above coarsening time follows a parabolic law. Regarding previous models and experimental results, the growth model of austenite grain in 36MnVS4 steel is established.

Key words
fracture splitting performance, austenite grain, heating temperature, holding time, mathematical model

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