Elongation enhancement strategies for AISI 430 stainless steel welded joints: insights from molecular dynamics analysis  

AISI 430不锈钢焊接接头的延伸率增强策略:来自分子动力学分析的见解

作　　者：Gongbo Bian Feng Liu Tingting Zhang Mengting Ran Xiaoyan Xue Dinglu Wu Wenxian Wang 卞功波;刘锋;张婷婷;冉孟庭;薛小炎;武定泸;王文先

机构地区：[1]College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China [2]Xi’an Seal Electronic Material Technology Co.,Ltd.,Xi’an 710000,China [3]College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China [4]Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment,Ministry of Education,Taiyuan 030024,China

出　　处：《Acta Mechanica Sinica》2025年第2期150-162,共13页力学学报(英文版)

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.52075360,52275360,and 51805359).

摘　　要：AISI 430 ferritic stainless steel is popular in modern industry,while conventional welding methods with filler metals produce welded joints with tensile strength(586 MPa)and elongation(7.35%),which is insufficient to meet the growing engineering requirements.In this work,the elongation of the joint is doubled(15.11%)while yield strength remains unchanged after post-weld heat treatment(PWHT).Microstructural analysis of heat affected zone(HAZ)reveals the transformation process between equiaxed ferrite,intergranular martensite,and intragranular acicular martensite in the welded joint at 750℃ and 800℃.Additionally,molecular dynamics simulations demonstrate the impact of various types of martensite on single crystals of ferritic stainless steel under tension.The results indicate that intergranular martensite and acicular martensite demonstrate transgranular fracture,while granular martensite exhibits intragranular fracture.Intergranular martensite and granular martensite are distributed near high-strain regions within the crystal,whereas acicular martensite is concentrated at the grain boundaries,away from the high-strain regions.The comparison of hardening parameters for different types of martensite reveals that granular martensite(58.98)has higher ductility than acicular martensite(97.40)and intergranular martensite(111.54).These findings are valuable for developing advanced stainless steel welded joints that balance high ductility and strength,meeting modern engineering demands.AISI 430铁素体不锈钢在现代工业中应用广泛,而传统的填充金属焊接方法得到的焊接接头具有抗拉强度(586 MPa)和延伸率(7.35%),不足以满足日益增长的工程需求.在这项工作中,经过焊后热处理(PWHT)后,接头的延伸率提高了一倍(15.11%),而屈服强度保持不变.热影响区(HAZ)的微观组织分析揭示了焊接接头在750℃和800℃下等轴铁素体、晶间马氏体和晶内针状马氏体之间的转变过程.此外,分子动力学模拟证明了不同类型马氏体在拉伸作用下对铁素体不锈钢单晶的影响.结果表明,晶间马氏体和针状马氏体表现为穿晶断裂,而粒状马氏体表现为沿晶断裂.晶间马氏体和粒状马氏体分布在晶体内部高应变区附近,而针状马氏体则集中分布在晶界处,远离高应变区.不同类型马氏体硬化参数的比较表明,粒状马氏体(58.98)比针状马氏体(97.40)和晶间马氏体(111.54)具有更高的塑性.这些发现对于开发兼顾高延性和高强度的先进不锈钢焊接接头,满足现代工程需求具有重要价值.

关 键 词：Welded joints Ductility enhancement AISI 430 ferritic stainless steel Post-weld heat treatment Molecular dynamics 

分 类 号：TG407[金属学及工艺—焊接]