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Sulfide stress corrosion cracking (SSCC) in crude oil field environment including hydrogen sulfide (H₂S) has been recognized as a materials failure mechanism. Welding residual stress generation and metallurgical change by fusion welding process increase the cracking driving force and reduce the resistance of brittle fracture as well as environmental fracture. On the base of this understanding, firstly, we analyzed welding residual stresses of welded ASTM A106 Gr B steel pipe using in the petrochemical plant. And next, SSCC tests were conducted to assess SSCC resistance of the weld with smooth specimens. From the result, influence of temperature on corrosion rate was sensitive in order of HAZ, base metal and weld metal. Therefore, the most sensitive region in the weld is HAZ, and its corrosion rate increases with the temperature of corrosion environment increase. And failure positions of the most cases among failed specimens were at HAZ of the weld. Low limit (σ_SSCC) of A106 Gr B steel pipe was assessed as 0.6 σ_y (7271.6N)

In this study, dissimilar material welding between Alloy617 and 12Cr steel was performed using buttering welding technology on to the 12Cr steel side. Then, the welding residual stress of dissimilar material weld was analyzed by the numerical method and the experimental method, after that, the stress amplitude including the welding residual stress was calculated using a modified Goodman equation.

The residual stress beneath the surface is crucial to the safety of the structures. Neutron Diffraction and Hole-drilling are the two methods being used to measure the inner residual stress. Longitudinal Critically Refracted (LCR) wave transmission that is propagated parallel to surface also can be used for measuring residual stress, but measurements are within an effective depth and need to be further studied. In this paper, the parameters of K are separately tested in WZ, HAZ and BM zone. The welding process of 6082-T6 aluminum alloy welded joints is simulated in SYSWELD, the finite element model has been verified by the X-ray diffraction method. The residual stress value calculated by SYSWELD and the values obtained from the ultrasonic measurement show a good agreement. It is demonstrated that the residual stress of 6082-T6 aluminum alloy welded plate can be evaluated by using the ultrasonic method.

Research in LNG fueled ships are actively underway in the world. Accordingly, various materials were widely used as materials for storage tanks for ultra-low temperatures, and high manganese steel for ultra-low temperature was recently developed. In this paper, the transient thermal and residual stress analysis of the welding of 9% nickel steel and high manganese steel are presented. 9% nickel steel tended to have higher transverse direction stress and longitudinal direction stress than high manganese steel.

The purpose of this paper is to investigate the influence of welding residual stress (WRS) of the liquefied natural gas (LNG) fuel tank. In general, WRS and distortions are caused by non-uniform temperature distribution by the welding heat source. This will not only cause a brittle fracture, local buckling and corrosion damage, but also adversely affect the fatigue strength of the welded structures. Since LNG is treated at cryogenic temperatures of −162${}^{\circ }$C, leakage of LNG from the fuel tank to the outside may cause cracks in the hull and tank support system and cause severe damage. Therefore, it is necessary to predict the thermal behavior and WRS before welding is carried out. In this study, the WRS is calculated by thermal stress analysis based on the temperature distributions over time obtained from the transient thermal analysis. The results of this study can be used as a fundamental research for WRS analysis of plasma arc welding applied to LNG fuel tanks for coastal vessels.

The head penetration nozzle of control rod driving mechanism (CRDM) is known to be susceptible to primary water stress corrosion cracking (PWSCC) due to the welding-induced residual stress. Especially, the J-groove dissimilar metal weld regions have received many attentions in the previous studies. However, even though several advanced techniques such as weight function and finite element alternating methods have been introduced to predict the occurrence of PWSCC, there are still difficulties in respect of applicability and efficiency. In this study, the extended finite element method (XFEM), which allows convenient crack element modeling by enriching degree of freedom (DOF) with special displacement function, was employed to evaluate structural integrity of the CRDM head penetration nozzle. The resulting stress intensity factors of surface cracks were verified for the reliability of proposed method through the comparison with those suggested in the American Society of Mechanical Engineering (ASME) code. The detailed results from the FE analyses are fully discussed in the manuscript.