Q500 qE高性能桥梁钢断裂韧性CTOD试验研究

摘要

The fracture toughness( CTOD) of Q500qE high-performance bridge steel and welded joints were studied in this paper,w ith consideration of different steel thickness. T he focus w as the anti-fracture properties of Q500qE high-performance bridge steel and welded joints at different temperature. Research results reveal that the fracture toughness( CTOD) of 32 mm and 44 mm thickness Q500qE base metal changes little with decreasing temperature while that of 60 mm thickness Q500qE base metal is decreased obviously once temperatures down to -40 ℃. T he fracture toughness( CTOD) of various thickness of Q500qE weld metal is lower than that of the base metal. As the temperature drops,the fracture toughness( CTOD) of Q500qE weld metal is significantly reduced. In particular,the decrease of fracture toughness is more significant for 44 mm and 60 mm thickness Q500qE weld. It indicates that the fracture resistance of Q500qE weld metal is lower than that of the base metal,especially at low-temperature. Except for the base metal of 60 mm thickness Q500qE at -50℃,the CTOD values of other Q500qE base metal was within the acceptable areas of failure assessment curve( FAD diagram) and the fracture toughness( CTOD) values are qualified. For 32,44,60 mm thickness of Q500qE weld metal,the fracture toughness( CTOD) at room temperature is qualified. On the other hand,only the fracture toughness( CTOD) of 32 mm thickness of Q500qE weld metal is qualified at -20℃. Compared with the base metal,the fracture resistance of Q500qE weld metal at low temperature is poor. It is suggested that further research is needed for the performance of Q500qE welded material.%针对不同厚度规格的Q500 qE高性能桥梁钢母材和焊接接头，在不同温度条件下进行了断裂韧性CTOD试验，旨在系统研究 Q500qE高性能桥梁钢母材及其焊接接头的断裂抗力随温度的变化规律。试验结果表明：随着温度的降低，32和44 mm 板厚 Q500qE 母材的断裂韧性变化不大，但60 mm 板厚Q500 qE母材的断裂韧性在温度降至－40℃以下后，有较大幅度的降低；各种板厚的 Q500 qE 焊缝的断裂韧性都比母材低；随着温度的下降，Q500qE 焊缝的断裂韧性大幅降低，特别是44和60 mm 板厚Q500 qE焊缝。说明 Q500 qE焊缝的抗断性能，尤其是低温抗断性能比母材要差很多。评定结果表明：除60 mm板厚 Q500qE母材－50℃时的CTOD值外，其它各种板厚 Q500qE 母材的 CTOD 值均在失效评定曲线 FAD图的可接受区域内，其断裂韧性值是合格的；32，44，60 mm 板厚的 Q500qE 焊缝，仅有常温及32 mm板厚在－20℃的断裂韧性是合格的，与母材相比，Q500qE 焊缝的低温抗断性能较差。所以，对于 Q500 qE高性能桥梁钢需要进一步加强对焊缝性能的改善研究。