The Effect of Pipe Thickness on Residual Stresses due to Girth Welds

1982 ◽  
Vol 104 (3) ◽  
pp. 204-209 ◽  
Author(s):  
E. F. Rybicki ◽  
P. A. McGuire ◽  
E. Merrick ◽  
J. Wert
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
304 Stainless Steel ◽  
Stress Distributions ◽  
Intergranular Stress Corrosion ◽  
Steel Pipes ◽  
Inner Surface ◽  
Girth Welds ◽  
Intergranular Stress Corrosion Cracking

This paper addresses the question of what effect the pipe thickness has on weld residual stresses in 304 stainless steel piping. Two diameters are considered. These are nominal 4-in. and 10-in. diameters. Four pipe wall thicknesses corresponding to schedules 10, 40, 80, and 160 are examined for each pipe. The focus is on residual stress distributions on the pipe inner surface because this is a primary site for intergranular stress corrosion cracking in 304 stainless steel pipes. The trends in residual stress values are toward more compressive stresses at the pipe inner surface for thicker pipes with the same nominal diameter. Residual axial stresses for the thick 10-in. schedule 160 pipe were found to be compressive while those for the thinner schedule 80 pipe were tensile. X-ray residual stress data for a 6-in-dia schedule 160 pipe fall between the results for the 4-in. and 10-in. schedule 160 pipes and support the findings of the study.

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.

Residual Stress Simulation in Multi-Pass Weld of Stainless Steel Pipes

2012 ◽  
Vol 578 ◽  
pp. 82-86 ◽  
Author(s):  
Long Shi Gao
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Mechanical Analysis ◽  
304 Stainless Steel ◽  
The Finite Element Method ◽  
Steel Pipes ◽  
Integrity Assessment ◽  
Temperature Distributions ◽  
Stress Simulation

Multi-pass welds are used in pipes with stainless steel. The complicated temperature field and residual stresses in these welded structures are very important. The finite element method is used to simulate residual stress in multi-pass butt-welds in this paper. Element birth technique is implemented to model multi-pass welded 304 Stainless Steel Pipes. One-way coupled Thermo-mechanical analysis is adopted to calculate the residual stresses, that the structural analysis takes the temperature distributions as thermal input. The results provide reference for the structure integrity assessment of welded pipes.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (3) ◽  
pp. 188-192 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (1) ◽  
pp. 42-46 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Improvement of Residual Stresses of Circumferential Joint of Pipe by Heat-Sink Welding

1986 ◽  
Vol 108 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Y. Ueda ◽  
K. Nakacho ◽  
T. Shimizu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Heat Sink ◽  
Welding Residual Stress ◽  
Water Cooling ◽  
Intergranular Stress Corrosion ◽  
Steel Pipes ◽  
Nuclear Plants ◽  
Intergranular Stress Corrosion Cracking ◽  
Theoretical Analyses

Intergranular stress corrosion cracking may occur in some specific conditions on the inner surface of the welded joints of stainless steel pipes which are furnished in nuclear plants. One of the remedies for this cracking is to convert welding residual stress on this surface into compression. In this research, in order to improve welding residual stress, the authors investigated the effectiveness of the heat-sink welding (water cooling) by conducting theoretical analyses and experiments on SUS 304 pipes of different sizes in comparison with the conventional welding. The mechanisms of production of residual stresses by both methods are clarified and conditions for effective application of the heat-sink welding such as limitation of heat input, procedure of welding are indicated.

On the Mechanics of Residual Stresses in Girth Welds

2006 ◽  
Vol 129 (3) ◽  
pp. 345-354 ◽  
Author(s):  
P. Dong
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Relative Importance ◽  
Stress Distributions ◽  
Unified Framework ◽  
Joint Geometry ◽  
Weld Residual Stress ◽  
Girth Welds ◽  
Welding Procedure

In this paper, some of the important controlling parameters governing weld residual stress distributions are presented for girth welds in pipe and vessel components, based on a large number of residual stress solutions available to date. The focus is placed upon the understanding of some of the overall characteristics in through-wall residual stress distributions and their generalization for vessel and pipe girth welds. In doing so, a unified framework for prescribing residual stress distributions is outlined for fitness-for-service assessment of vessel and pipe girth welds. The effects of various joint geometry and welding procedure parameters on through thickness residual stress distributions are also demonstrated in the order of their relative importance.

scholarly journals Residual Stresses Induced by Surface Working and Their Improvement by Emery Paper Polishing

2020 ◽  
Vol 4 (2) ◽  
pp. 21
Author(s):  
Makoto Hayashi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Diffraction Method ◽  
304 Stainless Steel ◽  
Heat Treated ◽  
Emery Paper ◽  
Type 304 ◽  
Type 304 Stainless Steel

In many of machine parts and structural components, materials surface would be worked. In this study, residual stresses on the surfaces were measured by X-ray diffraction method, and effects of surface working on the residual stresses were examined. In case of lathe machining of type 304 stainless steel bar, the residual stresses in circumferential directions are tensile, and those in axial directions are almost compressive. Highly tensile residual stresses in the circumferential directions were improved by emery paper polishing. 10 to 20 times of polishing changes high tensile residual stresses to compressive residual stresses. In the case of shot peening on a type 304 stainless steel plate, the compressive residual stress inside is several hundred MPa lower than that on the surface. By applying the emery paper polishing to the shot peened surface 10 or 20 times, the residual stress on the surface is improved to −700 MPa. While fatigue strength at 288 °C in the air of the shot peened material is 30 MPa higher than solution heat treated and electro-polished material, the fatigue strength of the shot peened and followed by emery paper polished material is 60 MPa higher. Thus, the emery paper polishing is simple and a very effective process for improvement of the residual stresses.

Residual Stresses Prediction for CO2 Laser Butt-Welding of 304-Stainless Steel

2006 ◽  
Vol 3-4 ◽  
pp. 125-130 ◽  
Author(s):  
Khaled Y. Benyounis ◽  
Abdul Ghani Olabi ◽  
M.S.J. Hashmi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Laser Power ◽  
Travel Speed ◽  
304 Stainless Steel ◽  
Hole Drilling ◽  
Design Matrix ◽  
Butt Welding ◽  
Input Variables

Residual stresses are an integral part of the total stress acting on any component in service. It is important to determine and/or predict the magnitude, nature and direction of the residual stress to estimate the life of important engineering parts, particularly welded components. This work aims to introduce experimental models to predict residual stresses in the heat-affected zone (HAZ). These models specify the effect of laser welding input parameters on maximum residual stress and its direction. The process input variables considered in this study are laser power (1.03 - 1.368 kW), travel speed (26.48 – 68.52 cm/min) and focal point position (- 1 to 0 mm). Laser butt-welding of 304 stainless steel plates of 3 mm thick were investigated using a 1.5 kW CW CO2 Rofin laser as a welding source. Hole-drilling method was employed to measure the magnitude, and direction of the maximum principal stress in and around the HAZ, using a CEA-06- 062UM-120 strain gauge rosette, which allows measurement of the residual stresses close to the weld bead. The experiment was designed based on Response Surface Methodology (RSM). Fifteen different welding conditions plus 5 repeat tests were carried out based on the design matrix. Maximum principal residual stresses and their directions were calculated for the twenty samples. The stepwise regression method was selected using Design-expert software to fit the experimental responses to a second order polynomial. Sequential F test and other adequacy measures were then used to check the models adequacy. The experimental results indicate that the proposed mathematical models could adequately describe the residual stress within the limits of the factors being studied. Using the models developed, the main and interaction effect of the process input variables on the two responses were determined quantitatively and presented graphically. It is observed that the travel speed and laser power are the main factors affecting the behavior of the residual stress. It is recommended to use the models to find the optimal combination of welding conditions that lead to minimum distortion.

Effects of Pipe Dimensions and Outer Surface-Buttering Weld Conditions on Residual Stress Distributions

2008 ◽  
Author(s):  
Nobuyoshi Yanagida
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Outer Surface ◽  
Hoop Stress ◽  
Axial Stress ◽  
Butt Joint ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Butt Joints ◽  
Inner Surface

Effects of pipe dimensions and outer surface-buttering weld conditions on residual stress distributions were evaluated using the finite element method. Residual stresses were analyzed for 508–mm-diameter (500A) pipe 38.1 mm thick, 508–mm-diameter (500A) pipe 15.1 mm thick, and 267–mm-diameter (250A) pipe 15.1 mm thick. After the residual stresses at pipe butt joints were analyzed, residual stresses at these joints subjected to the outer surface-buttering welds were analyzed. Residual stresses were determined for various weld widths, thicknesses, and heat inputs. These analyses indicate that tensile axial stress occurred at inner surface of the pipe butt joint and that it decreased with increasing the outer surface buttering-weld width or heat input. They also indicate that compressive hoop stress occurred at inner surface of the joint and that outer surface-buttering weld increased it. The outer surface-buttering weld conditions that generate compressive residual stress at the inner surface of the pipe butt joints were determined.

Sign in / Sign up

Export Citation Format

Share Document