焊接热输入对12MnNiVR钢接头组织与性能影响  

Influence of welding heat input on microstructure and properties of 12MnNiVR steel joints

作　　者：王锟艺 刘兆龙 刘坤 范益 李伟 邹家生[1] WANG Kunyi;LIU Zhaolong;LIU Kun;FAN Yi;LI Wei;ZOU Jiasheng(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212100,China;ShanghaiWaigaoqiao Shipbuilding Co.Ltd.,Shanghai 200137,China;Jiangsu Key Laboratory for Premium Steel Materials,Nanjing Iron&Steel Co.Ltd.,Nanjing 210035,China)

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212100 [2]上海外高桥造船有限公司,上海200137 [3]南京钢铁股份有限公司江苏省高端钢铁材料重点实验室,南京210035

出　　处：《江苏科技大学学报(自然科学版)》2024年第6期52-57,共6页Journal of Jiangsu University of Science and Technology:Natural Science Edition

基　　金：国家自然科学基金项目(52105351);江苏省自然科学基金项目(BK20210890)。

摘　　要：采用气电立焊对12MnNiVR钢进行焊接,分析了焊接热输入对接头的微观组织和力学性能的影响,重点研究了焊接接头的冲击韧性.结果表明:焊缝组织主要为针状铁素体和粒状贝氏体,存在马氏体-奥氏体(M-A)组元,粗晶热影响区组织为板条铁素体,夹杂物为TiN.随着焊接热输入的增加,针状铁素体和板条铁素体逐渐转变为块状铁素体,且块状铁素体尺寸逐渐增大,M-A组元数量和尺寸也增加.焊缝显微硬度和热影响区最高显微硬度随着焊接热输入的增加而降低.焊接接头的拉伸和弯曲性能均满足标准,冲击韧性随着焊接热输入的增加而降低,焊缝处冲击断口呈现韧窝特征,随着焊接热输入的增加,热影响区处冲击断口的断裂方式由韧性断裂转变为准解理断裂.厚度为21.5 mm的12MnNiVR钢焊接热输入宜控制在100 kJ/cm以下,以保证接头在具有良好的综合力学性能的同时兼顾较高的生产效率.We weld 12MnNiVR steel by gas-electric vertical welding method and study the influence of welding heat input on the microstructure and mechanical properties of the joint and focus on the impact toughness of the joints. The results show that the microstructure of weld is mainly composed of acicular ferrite and granular bainite. Martensite-Austenite(M-A) components are also observed. The microstructure of the coarse-grained heat-affected zone is lath ferrite, and the inclusions are identified as TiN. With increasing welding heat input, acicular ferrite and lath ferrite gradually transform into massive ferrite. The size of massive ferrite increases gradually and the number and size of M-A components also increas. The microhardness of the weld seam and the maximum microhardness of the heat-affected zone both decrease with increasing welding heat input. The tensile and bending properties of the joints meet the standards. The impact toughness decreases with increasing welding heat input and the impact fracture at the weld seam presents dimple characteristics. With increasing welding heat input, the fracture mode of the impact fracture at the heat affected zone changes from ductile fracture to quasi cleavage fracture. Finally, this paper proposes that the welding heat input of 12MnNiVR steel with a thickness of 21.5 mm should be controlled below 100 kJ/cm to ensure that the joint has good comprehensive mechanical properties and high production efficiency.

关 键 词：12MnNiVR钢 气电立焊 焊接热输入 组织 力学性能 

分 类 号：TG446[金属学及工艺—焊接]