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
王锟艺 1刘兆龙 2刘坤 1范益 3李伟 4邹家生1
作者信息
- 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
- 4. 江苏科技大学材料科学与工程学院,镇江 212100;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
- 折叠
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.
Abstract
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 bain-ite.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,acicu-lar 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 maxi-mum 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 in-put,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Key words
12MnNiVR steel/gas-electric vertical welding/welding heat input/microstructure/mechanical properties引用本文复制引用
出版年
2024
NETL
NSTL
万方数据