Research Article A Numerical Approach to Analyze Detail Mechanical Characteristic at the Crack Tip of SCC in Dissimilar Metal Welded Joints He Xue , 1 Yuman Sun , 1 Shun Zhang , 1 Rehmat Bashir , 1,2 Youjun Zhao, 1 Hongliang Yang , 3 Shuai Wang , 1 and Yongjie Yang 1 1 School of Mechanical Engineering, Xi’an University of Science and Technology, Xi’an 710054, China 2 Department of Mechanical Engineering, University of Engineering and Technology, Lahore 54890, Pakistan 3 Center of Engineering Training, Xi’an University of Science and Technology, Xi’an 710054, China Correspondence should be addressed to He Xue; xuehe@xust.edu.cn and Yuman Sun; 19205201061@stu.xust.edu.cn Received 12 April 2021; Revised 9 August 2021; Accepted 13 August 2021; Published 23 August 2021 Academic Editor: Paolo Ferro Copyright © 2021 He Xue et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e mechanical characteristic at the crack tip is one of the main factors aﬀecting the stress corrosion cracking (SCC) in dissimilar metal welded joints (DMWJs). In this research, to evaluate the eﬀect of heterogeneous material properties on the mechanical characteristic at the crack tip of DMWJs accurately, a heterogeneous material model of the SA508 Cl.3-Alloy 52M DMWJ was established based on USDFLD subroutine in ABAQUS. e comparison of the traditional “Sandwich” material model with the heterogeneous material properties, stress-strain conditions, and the plastic zone around the crack tip at the interference zone has been analyzed by the ﬁnite element method (FEM). e results indicated that the heterogeneous material model could characterize the mechanical properties of the SA508 Cl.3-Alloy 52M DMWJs accurately. In addition, the crack at the interface zone between materials will deﬂect along with the weld metal in two material models. 1. Introduction Nickel base alloys, such as alloy 152/52M, alloy 182/82, and alloy 309L/308L, have been widely used as weld metals to connect the pipe nozzle and safety end of the primary circuit of the nuclear pressure vessel [1–5]. However, several studies have demonstrated that the distribution of microstructure and material mechanical properties in the heat-aﬀected zone (HAZ) and dilution zone (DZ) of the welded joint has become much complex during the welding progress [6–11]. Meanwhile, the complicated mechanical characteristic at the crack tip caused by the heterogeneous material properties is one of the main factors for stress corrosion cracking (SCC) of dissimilar metal welded joints (DMWJs) [12]. erefore, there is a great signiﬁcance to characterize the material mechanical properties of DMWJs in detail for the safety evaluation and life prediction of the DMWJ in service environments. Considerable research eﬀorts have been devoted to the inﬂuence of the material constraint eﬀect of welded joints on the mechanical characteristic at the crack tip by ﬁnite ele- ment method (FEM). Some scholars studied the mechanical characteristic at the crack tip of DMWJs based on the “Sandwich” material model, which ignores the existence of the HAZ and DZ and endows corresponding material properties to the base metal and weld metal [13, 14], re- spectively. erefore, the traditional “Sandwich” material model can only roughly evaluate the inﬂuence of mismatch of the material mechanical properties between the base metal and weld metal on the safety of welded joints. However, the material mechanical properties of the DMWJ are not dis- tinguished strictly at the interface zones between materials. Recent experiments in this ﬁeld have obtained the material mechanical properties of the SA508 Cl.3-Alloy 52M DMWJ by microhardness test or minisized tensile test [15, 16]. e experimental results show dramatic changes in the strength Hindawi Advances in Materials Science and Engineering Volume 2021, Article ID 8429051, 12 pages https://doi.org/10.1155/2021/8429051