600 MPa级Ti、Nb析出强化车轮钢接头硬度及热影响区软化行为分析  

The hardness and softening behavior of HAZ in Ti and Nb precipitation strengthened 600 MPa wheel steel

作　　者：董现春 刘新垚 蔡宁 张大伟 张侠洲 李学涛 Dong Xianchun;Liu Xinyao;Cai Ning;Zhang Dawei;Zhang Xiazhou;Li Xuetao(Research Institute of Technology of Shougang Group Co.,Ltd.,Beijing 100043,China;Beijing Key Laboratory of Green Recycling Process for Iron&Steel Production Technology,Beijing 100043,China;Beijing Engineering Research Center of Energy Steel,Beijing 100043,China)

机构地区：[1]首钢集团有限公司技术研究院,北京100043 [2]绿色可循环钢铁流程北京市重点实验室,北京100043 [3]北京能源用钢工程研究中心,北京100043

出　　处：《钢铁钒钛》2023年第6期192-197,共6页Iron Steel Vanadium Titanium

摘　　要：采用连续闪光对焊技术,焊接600 MPa级Ti,Nb析出强化车轮钢,制造22.5×9.0车轮的轮辋。采用气体保护焊技术,焊接轮辋与轮辐的搭接接头。轮辋闪光对焊接头在扩口工序出现开裂、辊型工序出现减薄、扩张工序出现开裂,综合报废率37%。车轮径向疲劳试验80万转时,轮辋与轮辐搭接焊缝发生焊根部位的疲劳开裂。对车轮钢接头的断口、组织、硬度、析出相进行分析。结果表明,对焊接头硬度呈现“马鞍形”局部软化特征,搭接接头硬度呈现“盆地形”局部软化特征。热影响区中,过热区晶粒长大,20 nm以下第二相粒子大量溶解,正火区晶粒长大,20 nm以下第二相粒子消失伴随20 nm以上第二相粒子熟化,造成热影响区软化。A 22.5×9.0 wheel rim made of Ti and Nb precipitation strengthened 600 MPa wheel steel was manufactured by continuous flash butt welding process to.The lap joint of rim and spoke was welded under gas shielded welding process.The flash butt welded joint of the rim cracked during the flaring process,thinned during rolling forming process and cracked during expansion process.Consequently,the comprehensive scrap rate was 37%.When the wheel was subjected to radial fatigue test for 800000 cycles,fatigue cracking occurred at the weld root of the lap between the rim and the spoke.The fracture,microstructure,hardness and precipitated phase of wheel steel joint were analyzed.The results show that the hardness of butt welded joints presents"saddle"local softening characteristics,and the hardness of lap joints presents"basin"local softening characteristics.In the CGHAZ the grains coarsen,while the second phase particles below 20 nm dissovle significantly.In the FGHAZ the grains grow,with the second phase particles below 20 nm disappear and particles above 20 nm coarsen,leading to softening behavior of HAZ.

关 键 词：车轮钢 析出强化 接头硬度 HAZ软化 第二相粒子 

分 类 号：TF76[冶金工程—钢铁冶金] TG456[金属学及工艺—焊接]