电力铁塔专用Q420角钢性能研究

Study on Performance of Q420 Angle Iron for Power Tower

采用三组不同成分的Q420角钢做常温拉伸试验、低温冲击试验,其中两组成分试验作为一组成分的对比。由三种不同成分的拉伸试验结果与金相组织可知:一组成分的含钒量增加,晶粒细化,从而强度增大。其中一组成分角钢又分为四种不同终轧温度,通过实验研究终轧温度对角钢低温韧度的影响。结果表明:随着终轧温度的降低,角钢的冲击韧度逐渐降低;在860℃终轧温度低温冲击韧度达到最大,而986℃终轧温度的最小;用电子扫描显微镜对四种不同终轧温度角钢在-40℃低温冲击试验的断口进行分析,从SEM断口形貌照片中可知:终轧温度为857和873℃角钢-40℃低温下发生韧性断裂;终轧温度为924和986℃角钢发生脆性断裂,与低温冲击试验结果相符合。

The tensile strength and low-temperature impact of three kinds of Q420 angle irons with different composition were carried out,two results of them were taken as a contrast to another.The testing results and theirmicrostructure show that the one with a higher vanadium content and smaller crystal grain has a high strength.The other with different finishing temperature was tested to study the influence of finishing temperature on its low-temperature flexibility.The results show that,with the decrease of finishing temperature,the low-temperature impact ductility decreases gradually.And the low-temperature flexibility is highest at finishing temperature of 860 ℃ and lowest at finishing temperature of 986 ℃.The fracture morphologies of four angle irons with different finishing temperature after impacted at-40 ℃ were analyzed by SEM.The results show that there is a ductile fracture at 857 ℃ and 873 ℃,brittle fracture at 924 ℃ and 986 ℃,which is in accord with the data of impact ductility test.