摘要
为提高960 MPa高强钢焊缝金属综合力学性能,揭示了960 MPa高强钢焊缝金属中Ti元素的最佳含量。首先,设计并焊接了4种不同Ti含量(0.01%~0.08%)的焊缝金属,通过扫描电子显微镜、能谱仪、拉伸与冲击试验,系统研究了Ti含量对焊缝微观结构与力学性能的影响。结合断口观察与断口显微形貌,评估了Ti含量对起裂能和扩展能的影响。结果表明,当Ti含量小于0.06%时,焊缝金属显微组织由粒状贝氏体转变为粒状贝氏体+针状铁素体;随着Ti含量提升,针状铁素体含量显著增加。当Ti含量达到0.06%时,抗拉强度为939 MPa,延伸率为23.5%,相较于Ti0.01延伸率提升27%,-40℃冲击功为104 J;Ti含量增至0.08%时,粗大板条贝氏体的形成与TiN的析出导致塑韧性急剧下降,延伸率降至18.2%,-40℃冲击功仅为25 J。Ti通过形成TiO2夹杂物促进针状铁素体形核,改善了焊缝的综合力学性能,但过量的Ti会诱发脆性相析出与粗大的板条贝氏体的形成,显著恶化塑韧性。
In order to improve the comprehensive mechanical properties of 960 MPa high strength steel weld metal,the optimum content of Ti element in 960 MPa high strength steel weld metal was revealed.Firstly,four kinds of weld metals with different Ti contents(0.01%-0.08%)were designed and welded.The effects of Ti content on the microstructure and mechanical properties of welds were systematically studied by scanning electron microscopy,energy dispersive spectroscopy,tensile and impact tests.The effect of Ti content on the initiation energy and propagation energy was evaluated by fracture observation and fracture morphology.The results show that when the Ti content is less than 0.06%,the microstructure of the weld metal changes from granular bainite to granular bainite+acicular ferrite.With the increase of Ti content,the content of acicular ferrite increases significantly.When the Ti content reaches 0.06%,the tensile strength reaches 939 MPa,the elongation reaches 23.5%,the elongation increases by 27%compared with Ti0.01,and the impact absorption energy at-40℃reaches 104 J;when the Ti content increases to 0.08%,the formation of coarse lath bainite and the precipitation of TiN lead to a sharp decrease in plasticity and toughness,the elongation decreases to 18.2%,and the impact energy at-40℃is only 25 J.Ti promotes the nucleation of acicular ferrite and improves the comprehensive mechanical properties by forming TiO2 inclusions.However,excessive Ti will induce the precipitation of brittle phase and the formation of coarse lath bainite,which significantly deteriorates the plasticity and toughness.
作者
刘梓申
曹睿
焦世舜
杨飞
朱宇霆
张克静
刘春桃
LIU Zishen;CAO Rui;JIAO Shishun;YANG Fei;ZHU Yuting;ZHANG Kejing;LIU Chuntao(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Atlantic China Welding Consumables Co.,Ltd.,Zigong 643000,China)
出处
《机械强度》
北大核心
2025年第9期182-189,共8页
Journal of Mechanical Strength
基金
甘肃省重点研发计划(23YFGA0057)
甘肃省拔尖领军人才项目
中央引导地方科技发展专项(24ZYQA054)
国家自然科学基金项目(52175325,51961024,52071170)
甘肃省科技重大专项(23ZDGA010,22ZD6GA008)。
作者简介
刘梓申,男,2001年生,河北唐山人,在读博士研究生,主要研究方向为焊缝金属强韧化,E-mail:lzsliuzishen@163.com。;通信作者:曹睿,女,1977年生,甘肃兰州人,博士,教授,主要研究方向为新材料、异种材料的焊接性、强韧性、腐蚀、变形、损伤及断裂行为,E-mail:caorui@lut.edu.cn。
