A Computational Model for Improving Weld Residual Stresses in Small Diameter Pipes by Induction Heating

1981 ◽  
Vol 103 (3) ◽  
pp. 294-299 ◽  
Author(s):  
E. F. Rybicki ◽  
P. A. McGuire
Keyword(s):  
Residual Stresses ◽  
Induction Heating ◽  
Laboratory Data ◽  
Small Diameter ◽  
Computational Results ◽  
Computational Capability ◽  
Inner Surface ◽  
Girth Welding ◽  
Welded Pipe ◽  
Compressive Residual Stresses

Girth welding can produce tensile residual stresses on the pipe inner surface. Because tensile stresses enhance the possibility of stress corrosion cracking, methods for altering the weld-induced stress state are being investigated. One method, Induction Heating for Stress Improvement (IHSI), involves induction heating the pipe while cooling the inner surface. The method is being evaluated using both experimental and computational studies. This paper presents computational results of a 101.66-mm (4-in.) Schedule 80 stainless steel pipe. Results include comparisons of computed values for residual stresses with laboratory data. Computed values of residual stresses and laboratory data are in agreement and, for this case, clearly show that the IHSI process can change weld-induced tensile residual stresses to compressive values. A comparison of computational results for applying the IHSI process to a stress-free pipe and a welded pipe indicate that for geometry and process parameters considered here, the IHSI-induced compressive residual stresses on the pipe inner surface for these two cases are similar. The experimental results presented here show the feasibility of controlling weld-induced residual stresses. The computational results demonstrate a capability for predicting the observed stress behavior. The computational capability then provides an efficient tool to aid in developing ways for controlling residual stresses for other pipe sizes and weldment geometries.

A Computational Model of Backlay Welding for Controlling Residual Stresses in Welded Pipes

1981 ◽  
Vol 103 (3) ◽  
pp. 226-232 ◽  
Author(s):  
F. W. Brust ◽  
E. F. Rybicki
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Computational Model ◽  
Welding Process ◽  
Computational Results ◽  
Intergranular Stress Corrosion ◽  
Inner Surface ◽  
Piping Systems ◽  
Intergranular Stress Corrosion Cracking ◽  
Compressive Residual Stresses

Intergranular Stress Corrosion Cracking (IGSCC) has been a problem in Boiling Water Reactor (BWR) piping systems. One method for retarding IGSCC is to eliminate tensile residual stresses at the pipe inner surface in the heat affected zone produced by the welding process. A method called backlay welding can be effective in producing compressive residual stresses at the pipe inner surface. This paper describes a computational model and its use in examining the effectiveness of the backlay welding process. The model has demonstrated an ability to predict weld-induced residual stresses for a variety of pipe sizes and welding conditions. Computational results for backlay welding are in agreement with residual stress data. The mechanisms causing residual stresses and the effect of the number of backlay weld layers on residual stresses are discussed.

The Effects of Induction Heating Conditions on Controlling Residual Stresses in Welded Pipes

1982 ◽  
Vol 104 (4) ◽  
pp. 267-273 ◽  
Author(s):  
E. F. Rybicki ◽  
P. A. McGuire
Keyword(s):  
Residual Stresses ◽  
Induction Heating ◽  
Outer Surface ◽  
304 Stainless Steel ◽  
Residual Stress State ◽  
Surface Temperatures ◽  
Inner Surface ◽  
Induced Stresses ◽  
Welded Pipe ◽  
Type 304

Induction heating for stress improvement (IHSI) is a method for reducing the tensile weld induced stresses on the inner surfaces of the girth welded pipes. The process entails inductively heating the outside of a welded pipe while cooling the inner surface with flowing water. A 10-in. Schedule 80 Type 304 stainless steel pipe was selected for this study. Residual stresses due to welding were first determined using a finite element computational model. Several IHSI treatments subsequent to welding are then examined computationally to determine the effect of induction coil length and maximum outer surface temperatures on the final residual stress state. All IHSI treatments gave reduced inside surface tensile weld induced stresses on the inner surface. Longer coils and higher outer surface temperatures led to inner surface stresses that were more compressive.

Effects of Residual Stress on Fatigue Strength of Small-Diameter Welded Pipe Joint

1997 ◽  
Vol 119 (4) ◽  
pp. 428-434 ◽  
Author(s):  
T. Yamashita ◽  
T. Hattori ◽  
K. Iida ◽  
T. Nomoto ◽  
M. Sato
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Local Stress ◽  
Element Analysis ◽  
Fillet Weld ◽  
Pipe Joints ◽  
Welded Pipe

Bending fatigue tests were conducted to investigate the fatigue strength of small-diameter socket welded pipe joints. In most cases of large-diameter socket joints, a fatigue crack started from the root of the fillet weld, though the stress amplitude at the root was smaller than that at the toe of the fillet weld. Additionally, the fatigue strength was affected by the weld bead sequence. The residual stress was considered to be one of the important parameters governing fatigue strength; therefore, its effects were investigated. In several types of pipe joints, the local stress and residual stress distributions were calculated by finite element analysis. The residual stresses were compressive at the toe and tensile at the root of the socket welded joints. Based on these results, the effects of residual stresses on the fatigue strength are discussed for small-diameter welded pipe joints in the present work.

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

scholarly journals Thermal Effects on Surface and Subsurface Modifications in Laser-Combined Deep Rolling

2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Robert Zmich ◽  
Daniel Meyer
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Thermal Loads ◽  
Deep Rolling ◽  
Mechanical Loads ◽  
Thermomechanical Process ◽  
Compressive Stresses ◽  
New Process ◽  
Negative Effect ◽  
Compressive Residual Stresses

Knowledge of the relationships between thermomechanical process loads and the resulting modifications in the surface layer enables targeted adjustments of the required surface integrity independent of the manufacturing process. In various processes with thermomechanical impact, thermal and mechanical loads act simultaneously and affect each other. Thus, the effects on the modifications are interdependent. To gain a better understanding of the interactions of the two loads, it is necessary to vary thermal and mechanical loads independently. A new process of laser-combined deep rolling can fulfil exactly this requirement. The presented findings demonstrate that thermal loads can support the generation of residual compressive stresses to a certain extent. If the thermal loads are increased further, this has a negative effect on the surface layer and the residual stresses are shifted in the direction of tension. The results show the optimum range of thermal loads to further increase the compressive residual stresses in the surface layer and allow to gain a better understanding of the interactions between thermal and mechanical loads.

scholarly journals Research on on-line ultrasonic testing of small diameter thin wall stainless steel straight welded pipe

2021 ◽  
Vol 1820 (1) ◽  
pp. 012086
Author(s):  
Huaishu Hou ◽  
Ding Lu ◽  
Shiwei Zhang ◽  
Yi Zhang ◽  
Chaolei Cheng
Keyword(s):  
Stainless Steel ◽  
Ultrasonic Testing ◽  
Small Diameter ◽  
Thin Wall ◽  
On Line ◽  
Welded Pipe ◽  
Wall Stainless Steel

scholarly journals Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Suvi Santa-aho ◽  
Mika Kiviluoma ◽  
Tuomas Jokiaho ◽  
Tejas Gundgire ◽  
Mari Honkanen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Sample Surface ◽  
Post Processing ◽  
Magnesium Chloride Solution ◽  
Manufacturing Method ◽  
Four Point Bending ◽  
Traditional Manufacturing ◽  
Processing Steps ◽  
Compressive Residual Stresses

Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.

Ultrasonic Evaluation of Compressive Residual Stress of Surface Treated Metals

2005 ◽  
Vol 490-491 ◽  
pp. 184-189 ◽  
Author(s):  
Farid Belahcene ◽  
Xiaolai Zhou ◽  
Jian Lu
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Nondestructive Evaluation ◽  
Subsurface Layer ◽  
Surface Mechanical Attrition Treatment ◽  
Shallow Subsurface ◽  
Ultrasonic Evaluation ◽  
Mechanical Attrition ◽  
Machine Parts ◽  
Compressive Residual Stresses

Shot peening is an effective method of improving fatigue performance of machine parts in the industry by producing a thin surface layer of compressive residual stresses that prevents crack initiation and retards crack growth during service. Nondestructive evaluation of the prevailing compressive residual stresses in the shallow subsurface layer is realized by the critically refracted longitudinal (Lcr) waves. This paper presents experimental data obtained on SMAT (surface mechanical attrition treatment) steel alloy S355 sample. Comparative travel-time shows that there are statistically significant differences in treated and untreated specimen. With knowledge of the acoustoelastic constants which are obtained by a test calibration, the experimental data indicates that compressive residual stresses are distributed near subsurface (hundreds of micron). These stress results show that the Lcr technique is efficient for evaluation of residual stresses after the surface treatment.

The Residual Stresses Generated by Deep Rolling and their Stability in Fatigue & Application to Deep-Rolled Crankshafts

2006 ◽  
Vol 524-525 ◽  
pp. 45-50 ◽  
Author(s):  
H. Michaud ◽  
Jean Michel Sprauel ◽  
F. Galzy
Keyword(s):  
Residual Stresses ◽  
Fatigue Resistance ◽  
Experimental Validation ◽  
Crack Arrest ◽  
Cyclic Fatigue ◽  
Rolling Process ◽  
Fatigue Behaviour ◽  
Deep Rolling ◽  
Bending Fatigue ◽  
Compressive Residual Stresses

In this work, the effect of steel grade on the fatigue resistance of deep-rolled crankshafts is analysed. In the first part of this paper, the mechanisms leading to the increase of the fatigue resistance brought by the deep rolling treatment, is presented. This reinforcement is mainly linked to crack arrest due both to a decrease of the in-depth stress concentration factor and to remaining compressive residual stresses induced by the deep rolling. In a second part, an analytical model of residual stresses generation by deep-rolling and fatigue is presented. In this model the low cyclic fatigue behaviour of the steel is taken into account, and the residual stress stability with bending fatigue cycling can be predicted. After a presentation of the experimental validation on two different microstructures (baintic and ferrito- perlitic), this model is used for analysing the main parameters of the deep-rolling process and fatigue resistance.

Estimation of Residual Stress in Spiral Welded Pipe: Regression and Numerical Model

2012 ◽  
Author(s):  
Abul Fazal M. Arif ◽  
Ahmad S. Al-Omari ◽  
Anwar K. Sheikh ◽  
Yagoub Al-Nassar ◽  
M. Anis
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Critical Role ◽  
Large Diameter ◽  
Element Model ◽  
Regression Equation ◽  
Field Analysis ◽  
Welding Parameters ◽  
Splitting Test ◽  
Welded Pipe

Double submerged spiral-welded pipe (SWP) is used extensively throughout the world for large-diameter pipelines. Fabrication-induced residual stresses in spiral welded pipe have received increasing attention in gas, oil and petrochemical industry. Several studies reported in the literature verify the critical role of residual stresses in the failure of these pipes. Therefore, it is important that such stresses are accounted for in safety assessment procedures such as the British R6 and BS7910. This can be done only when detailed information on the residual stress distribution in the component is known. In industry, residual stresses in spiral welded pipe are measured experimentally by means of destructive techniques known as Ring Splitting Test. In this study, statistical analysis and linear-regression modeling were used to study the effect of several structural, material and welding parameters on ring splitting test opening for spiral welded pipes. The experimental results were employed to develop an appropriate regression equation, and to predict the residual stress on the spiral welded pipes. It was found that the developed regression equation explains 36.48% of the variability in the ring opening. In the second part, a 3-D finite element model is presented to perform coupled-field analysis of the welding of spiral pipe. Using this model, temperature as well as stress fields in the region of the weld edges is predicted.

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