铁路桥梁钢及焊缝的CTOD性能  

CTOD performance of railway bridge base steels and weld seams

作　　者：张玉玲[1] 王冒明[2] 吴新如[3] 孙振华[3] 陶晓燕[2] 

机构地区：[1]清华大学机械工程系,北京100084 [2]铁道科学研究院,北京100081 [3]清华大学工程力学系,北京100084

出　　处：《清华大学学报（自然科学版）》2005年第5期585-588,共4页Journal of Tsinghua University(Science and Technology)

基　　金：铁道部科技发展计划资助项目(2001G010A-2)

摘　　要：为了解铁路钢桥构件材料的弹塑性断裂韧性性能,对常用桥梁钢——Q370qE和Q345qD钢的各种板厚的母材、焊缝和熔合线试样进行了20℃至-70℃的直三点弯曲裂纹尖端张开位移(CTOD)试验。数据分析采用"个性化因素剔除"方法,回归得到随温度变化的CTOD临界值δ的通用计算公式。结果表明:δ在材料、温度、板厚不同的情况下,应分别取脆断、韧脆破坏和韧性破坏时的CTOD值;Q370qE钢母材在高于-70℃的环境温度下不会发生脆断,Q345qD钢母材的转脆温度为-42℃;两种钢材焊缝的CTOD性能相近,转脆温度为-24℃;CTOD性能可作为修订常规冲击韧性标准的依据。Three-point crack tip open displacement (CTOD) bend tests were made using Q370qE and Q345qD base steel, weld seam and melt line samples at various temperatures from 20 ℃ to -70 ℃ and at different sample thicknesses to study the elasto-plastic fracture toughness of the materials frequently used in steel railway bridges. An individuation-factor-elimination method was used to analyze the data with the relationship between the CTOD critical value, δ, and the temperature obtained by linear regression of the data. The results show that different CTOD values corresponding to the occurrence of brittle fracture before yield strength, brittle fracture after yield strength, and ductile fracture should be chosen as δ for different material types, temperatures and thicknesses. No brittle fracture occurrs in the Q370qE base steel at tempertures higher than -70 ℃ and that the plastic-brittle transition temperature is -42 ℃ for Q345qD base steel and -24 ℃ for both kinds of weld seams with similar CTOD toughnesses. The CTOD toughness can be used as the basis to amend the conventional impact toughness criterion.

关 键 词：铁路桥梁钢 弹塑性 断裂韧性 裂纹尖端张开位移(CTOD) 

分 类 号：U214.81[交通运输工程—道路与铁道工程]