Experimental and Numerical Investigation of Sub-Clad and Surface Cracks in Cladded Components

Author(s):  
Jo¨rg Hohe ◽  
Marcus Brand ◽  
Dieter Siegele

The present study is concerned with the fracture behavior of sub-clad and surface cracks in components consisting of ferritic steels with an austenitic welded cladding. For this purpose, two tests on large scale specimens have been performed. The residual stress field has been determined by means of a numerical simulation of the welding and heat treatment processes. Based on the results, a numerical simulation of the component tests was performed in order to enable a fracture mechanics assessment of the conditions leading to crack initiation and arrest in the ferritic and austenitic regions. It was observed that in the present tests failure was initiated in the ferritic material whereas the austenitic cladding remained stable even in the case of a limited crack extension in the ferritic base metal.

2010 ◽  
Vol 452-453 ◽  
pp. 577-580
Author(s):  
Masanori Kikuchi ◽  
Yoshitaka Wada ◽  
Yuto Shimizu ◽  
Yu Long Li

Fracture in heat affected zone (HAZ) in welding has been a serious problem for the integrity of machines. Prediction of fracture behavior due to the residual stress field in HAZ is important. In this paper, S-Version FEM(S-FEM) is applied to simulate the crack growth under thermal and residual stress fields. For evaluation of stress intensity factor, virtual crack closure integral method (VCCM) is employed. The residual stress data was provided by JAEA, Japan Atomic Energy Agency, based on their numerical simulation. SCC crack growth of a surface crack at inner suface of a pipe under thermal residual stress is simulated in three-dimensional filed. Distributions of residual stress is not axi-symmetric along pipe wall, and it affects the crack growth behavior. Ttwo cases, for axi-symmetric and non-symmetric thermal stress distributions, are assumed and crack growth behaviors are obtaiend and discussed.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 127
Author(s):  
Zichen Liu ◽  
Xiaodong Hu ◽  
Zhiwei Yang ◽  
Bin Yang ◽  
Jingkai Chen ◽  
...  

In order to clarify the role of different post-weld heat treatment processes in the manufacturing process, welding tests, post-weld heat treatment tests, and finite element analysis (FEA) are carried out for 12C1MoV steel pipes. The simulated temperature field and residual stress field agree well with the measured results, which indicates that the simulation method is available. The influence of post-weld heat treatment process parameters on residual stress reduction results is further analyzed. It is found that the post weld dehydrogenation treatment could not release residual stress obviously. However, the residual stress can be relieved by 65% with tempering treatment. The stress relief effect of “post weld dehydrogenation treatment + temper heat treatment” is same with that of “temper heat treatment”. The higher the temperature, the greater the residual stress reduction, when the peak temperature is at 650–750 °C, especially for the stress concentration area. The longer holding time has no obvious positive effect on the reduction of residual stress.


Author(s):  
Jinhua Shi ◽  
Liwu Wei ◽  
Poh-Sang Lam

Many stainless steel canisters for the dry storage of spent nuclear fuel are located in coastal regions. Because the heat treatment for relieving the welding residual stress is not required during fabrication, these canisters may be susceptible to chloride induced stress corrosion cracking due to the deliquescence of chloride-bearing marine salts or dust that enter the overpack system and deposit on the canister external surface. The NDE techniques and the associated delivery system are being developed to conduct periodic inservice inspections. The acceptance standards are needed to disposition findings should flaw-like indications be found. The instability crack lengths and depths for these flaws in the form of semi-elliptical shape near the welds are determined with R6 procedure. The cracks are subject to the canister design pressure and handling loads as well as the estimated welding residual stresses.


2016 ◽  
Vol 43 (8) ◽  
pp. 0802007
Author(s):  
汪静雪 Wang Jingxue ◽  
章艳 Zhang Yan ◽  
张兴权 Zhang Xingquan ◽  
戚晓利 Qi Xiaoli ◽  
裴善报 Pei Shanbao ◽  
...  

2011 ◽  
Vol 317-319 ◽  
pp. 386-392
Author(s):  
Yin Fei Yang ◽  
Ning He ◽  
Liang Li

The unknown and uneven macro-residual stresses in blanks will cause deformation on large-scale component, especially in non-prestretched plates. Based on the retrieval of stress field by measuring stress changes due to the rebalance of stresses after machining, a new idea is proposed in this paper to predict and control the machining deformation of large-scale components. It consists of analysis of the machining deformation, retrieval of macro-residual stress field, and finally optimization of following cutting process. In the retrieval process, the stresses are measured with an improved hole-drilling method and the measured data are then interpolated to 3D stress field.


2013 ◽  
Vol 345 ◽  
pp. 312-315 ◽  
Author(s):  
Bing Han ◽  
Yan Hua Wang ◽  
Chang Liang Xu

Water-jet cavitation peening is a new technology for surface modification of metallic materials. Compress residual stress layer is induced by impact wave pressure in the submerged cavitating jets processing. Based on ANSYS/LS-DYNA finite element analysis software, residual stress field in the SAE1070 spring steel material surface induced by cavitate-jet water peening process is simulated, the magnitude and variation rules of the residual stress along the layer depth under different conditions is obtained. In order to verify the correctness of the numerical simulation, the size and distribution of residual stress by the X-ray diffraction method. The results show that the numerical simulation and experimental results are well consistent.


2013 ◽  
Vol 433-435 ◽  
pp. 1898-1901
Author(s):  
Li Juan Cao ◽  
Shou Ju Li ◽  
Zi Chang Shangguan

Shot peening is a manufacturing process intended to give components the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. The modeling and simulation of the residual stress field resulting from the shot peening process are proposed. The behaviour of the peened target material is supposed to be elastic plastic with bilinear characteristics. The results demonstrated the surface layer affected by compressive residual stresses is very thin and the peak is located on the surface.


2009 ◽  
Vol 15 ◽  
pp. 109-114 ◽  
Author(s):  
G. Urriolagoitia-Sosa ◽  
E. Zaldivar-González ◽  
J.M. Sandoval Pineda ◽  
J. García-Lira

The interest on the application of the shot peening process to arrest and/or delay crack growth is rising. The main effect of the shot peening technique is to introduce a residual stress field that increases the working life of mechanical components. In this paper, it is presented the numerical simulation (FEM) of the shot peening process and the effect of introducing a residual stress field. Besides, the consequence of changing the sizes of the impacting ball is analyzed. This work also used the Crack Compliance Method (CCM) for the determination of residual stresses in beams subjected to a numerical simulation of a shot peening process. The numerical results obtained provide a quantitative demonstration of the effect of shot peening on the introduction of residual stresses by using different sizes of impacting balls and assess the efficiency of the CCM.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5423 ◽  
Author(s):  
Mato Perić ◽  
Sandro Nižetić ◽  
Zdenko Tonković ◽  
Ivica Garašić ◽  
Ivan Horvat ◽  
...  

In this study, we performed a numerical simulation and experimental measurements on a steel circular patch welded structure to investigate the temperature and residual stress field distributions caused by the application of buried-arc welding technology. The temperature histories during the welding and subsequent cooling process were recorded for two locations, with the thermocouples mounted inside the plate close to the weld bead. On the upper surface of the welded model, the temperature-time changes during the cooling process were monitored using an infrared camera. The numerically calculated temperature values correlated well with the experimentally measured ones, while the maximum deviation of the measured and calculated temperatures was within 9%. Based on the numerical result analysis regarding circumferential and radial stresses after the completion of the welding process, it is concluded that both stresses are primarily tensile within the circular disk. Outside the disk, the circumferential stresses turn from tensile to compressive, while on the other hand the radial stresses disappear towards the ends of the plate.


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