高强度钢材Q460C断裂韧性低温试验

研究了高强度结构钢材低温下的断裂韧性特征。对厚度为14mm的Q460C建筑钢材进行了裂纹尖端张开位移δm低温下的试验研究,并进行了试件断口电镜微观分析。结果表明-40℃下的Q460C三点弯曲试件断口呈明显的脆性断裂机制。Q460C钢材的δm值随温度降低呈下降趋势,与Q235、Q345、Q390钢材低温下的δm值比较,Q460C的值最低,即断裂韧性相对较差。同时,还对试验结果进行了Boltzmann函数拟合分析,得到其韧脆转变温度及变化规律。结果表明:Q460C高强度建筑钢材的低温冷脆特征明显。

Test on the fracture toughness of high-strength steel Q460C at low temperature

The fracture toughness characteristic of the high-strength steel at low temperature was studied.The crack tip opening displacement δm of construction steel Q460C with thickness 14 mm was tested at low temperature,and its fracture appearance was analyzed microscopically by an electronic microscope.It was found that at temperature-40 ℃,the fracture of the 3-point bending specimen of steel Q460C shows an obvious brittle fracture mechanism.The δm value of steel Q460C tends to decrease with the temperature reduction,which is less than those of steels Q235,Q345 and Q390,so the steel Q460C is characterized by the poorest fracture toughness among them.A Boltzmann function fitting analysis was performed to the test data,and the ductile-brittle transition temperature and its Changing behavior were obtained.The results showed an obvious cold brittle characteristic of the high-strength construction steel Q460C.