基于厚度法确定小冲杆试验能量转变温度

Research on the Ductile-Brittle Transition Temperature in Small Punch Experiment Based on Thickness Method

以A106管材钢为研究对象,进行了小冲杆断裂试验,获得断后试样的最小厚度;在对试样断裂后的变形分析中,建立了试样厚度减薄率与温度的关系,规避了低温试验中载荷和位移测量不准确导致小冲杆能量转变温度不确定的问题。结果表明:基于厚度法可以准确确定小冲杆断裂试验的能量转变温度;小冲杆断裂试验后,试样最薄厚度的减小率与温度曲线关系呈现S型,有上平台、转变区、下平台三个典型区域;根据厚度减薄率与温度曲线关系可以得到小冲杆的能量转变温度。采用厚度法得到的小冲杆断裂试验的转变温度与能量法获得的结果基本一致。

Taking A106 pipe steel as studied object,small punch fracture test was carried out to obtain the minimum thickness of fractured specimen. Based on the analysis of fractured specimen deformation,the relation between specimen thickness reduction ratio and temperature was established.The transition temperature uncertainty problem due to inaccurate measurement of load and displacement in low temperature small punch test was resolved.Results show that ductile-brittle transition temperature can be determined accurately based on thickness method in small punch test.In test,an S type relation curve between specimen minimum thickness reduction ratio and temperature is presented,where there are three typical regions：upper platform area,transition area and lower platform,respectively.The ductile-brittle transition temperature in small punch test can be obtained based on above curve.Results obtained from thickness method in small punch test basically agree with that obtained from energy method.