14MnNbq钢焊接热影响区韧性研究  

Study of Toughness of Heat Affected Zone of 14MnNbq Steel Welding

作　　者：焦伟[1] 张显辉[1] 谭长瑛[1] 

机构地区：[1]哈尔滨焊接研究所,黑龙江哈尔滨150081

出　　处：《中国铁道科学》2001年第5期85-88,共4页China Railway Science

摘　　要：芜湖长江大桥 14MnNbq钢梁实际焊接生产中 ,厚板焊接采用多层焊 ,这样热影响区 (HAZ)的每个区域可能会承受多次加热。当采用较大线能量焊接时 ,多次受热后的HAZ有可能进一步脆化。为了便于研究 ,文中采用Gleeble 15 0 0热模拟试验机模拟 14MnNbq钢焊接热影响区各区域的热循环 ,形成一个单一均匀放大的区域进行试验。进而确定最脆区域及其韧性。针对焊接过热脆化问题 ,将 14MnNbq钢与国外常用的桥梁钢SM 490C进行了对比试验 ,通过在相同的加热及冷却条件下 ,不同峰值时模拟热影响区的组织及韧性分析 ,对比两种钢对过热脆化的敏感性。由试验结果表明 ,14MnNbq钢焊接HAZ最脆区出现在一次热循环的埋弧焊过热区及二次热循环的埋弧焊过热区 +不完全重结晶区 ;14MnNbq钢比SM 490C钢有更强的过热脆化倾向 ,为确保焊接热影响区韧性 ,焊接时应适当控制焊接线能量。In the 14MnNbq steel welding on the beams of Wuhu Yangtze River bridge, multiple layer welding is used for thick plates, thus each HAZ (heat affected zone) may be subject to heating several times. When weld wire of high capacity is used for the welding, the HAZ may become crisp due to the repeated heating. In order to facilitate the research, the paper introduces the use of Gleeble 1500 heating simulation tester to simulate the heating cycles of each HAZ affected by 14MnNbq steel welding. Thus we have a single uniform enlarged zone for the test. And then we can further locate the crispest zone and determine its toughness. As for the issue of being crisp due to welding overheating, we made a comparison between the 14MnNbq steel and foreign SM490C bridge steel. Under the same heating and cooling conditions, we analyzed the structure and toughness of the simulated HAZ′s at various peaks values and compared the sensitivity of these two kinds of steel to overheat crispness. The test results show that the crispest HAZ occurs in the process of welding of the 14MnNbq steel on the first heat circulation submerged welding overheat zone and the second heat circulation submerged welding overheat zone plus the not entirely re crystallized zone. The 14MnNbq steel has a tendency of being crisper due to overheat than the SM490C steel is. In order to ensure the toughness of the welding HAZ′s, the welding wire capacity should be properly controlled during welding.

关 键 词：14MnNbp钢 焊接 热模拟 热影响区 过热脆化 芜湖长江大桥 韧性 钢梁 

分 类 号：U448.36[建筑科学—桥梁与隧道工程] TG457.11[交通运输工程—道路与铁道工程]