45钢超塑性的研究

The Investigation of Superplasticity of 45 Steel

对经过超细化处理的45钢试样,在不同变形温度及不同应变速率下进行了超塑性拉伸试验,并与退火状态试样作了对比,试验结果表明,在一定条件下45钢可以呈现良好的超塑状态。其应变速率敏感性指数m达0.6以上,最小流动应力为4.4MPa,最大拉伸延伸率达584%。试验中发现,当经超细化处理的45钢在Ac_1点进行恒温拉伸试验时,其超塑性延伸率指标出现一个陡峭的峰值。这一现象的发现对恒温超塑性机理的研究,以及建立比较合理的超塑性变形的模型,都将产生一定的影响. 本文的研究成果已在精密型腔模超塑成形技术中得到应用,显示了优质,高效的综合优势,具有广阔的应用前景.

In this paper, the tensile tests of superplastic deformation for the super refined samples of 45 steel under different deforming temperatures and strain rates were carried out and made comparison with the samples in annealling state.The results showed that under certain conditions, the steel presents superplasticity, the index of strain ratio sensitivity m≥0.6, minimum-flow stress is 4.4MPa, maximum elongation δ_(max) reaches up to 584%. And a precipitous peak value of δ is found in the super refined sample of the steel under constant temperature tensile test at its Ac_1 point The finding of this phynomina will effect on the research results about mechanism of constant temperature superplasticity and establishment of the model of superplastic deformation.This research achievement has been applied in the manufacture of precise dies and the comprehensive advantages of high quality and efficiency were obtained.