Evaluation of Residual Stresses Induced by Repairs to Small Diameter Stainless Steel Pipe Welds

2015 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Steel Pipe ◽  
Limited Information ◽  
Diameter Pipe ◽  
Stainless Steel Pipe ◽  
Lower Magnitude ◽  
The Impact

Residual stresses within stainless steel pipe welds may cause or exacerbate in-service cracking. Significant investigative efforts have been devoted to the examination of piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. Even less information is available for small diameter piping welds which have been repaired or re-worked during initial fabrication. This investigation used both experimental methods and analytical modeling to assess the impact of repair welding during initial fabrication on the residual stresses along the inner diameter (ID) of small diameter pipe specimens. The investigation showed that tensile axial residual stresses were located in the heat affected zone (HAZ) along the ID of the pipe specimens adjacent to regions which were excavated and re-welded. Such repair welds were also shown to markedly increase the magnitude of the tensile axial residual stresses for weld configurations which otherwise had lower magnitude residual stresses.

Residual Stress Evaluation of Small Diameter Stainless Steel Piping by Experimental Measurements and Finite Element Analysis

2014 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Axial Stress ◽  
Large Diameter ◽  
Small Diameter ◽  
Thick Wall ◽  
Outer Diameter ◽  
Thin Wall ◽  
The Impact

Residual stresses within stainless steel pipe welds may impact both component inspections and in-service cracking. Various investigators have examined piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. This investigation uses both experimental methods and analytical modeling to evaluate the impact of welding on the residual stresses along the inner diameter (ID) of two small diameter pipe specimens. Results of the investigation showed that tensile axial residual stresses were observed in the heat affected zone (HAZ) along the ID of the thin-wall pipe specimen with distinct regions of tensile and compressive axial stress which correlate well with the location where the last weld segments of the final weld pass were deposited. Higher stresses were also observed in the HAZ on the side where the final weld pass was deposited. By contrast, testing of the thick-wall pipe specimen showed significantly lower levels of tensile stresses along the pipe ID with the higher stress regions being biased toward the pipe outer diameter (OD).

scholarly journals Ultrasonic inspection of a welded stainless steel pipe to evaluate residual stresses through thickness

2013 ◽  
Vol 49 ◽  
pp. 591-601 ◽  
Author(s):  
Yashar Javadi ◽  
Hamed Salimi Pirzaman ◽  
Mohammadreza Hadizadeh Raeisi ◽  
Mehdi Ahmadi Najafabadi
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Ultrasonic Inspection ◽  
Steel Pipe ◽  
Stainless Steel Pipe

Evaluation of Residual Stresses in Small Diameter Stainless Steel Pipe Welds by Two-Dimensional and Three-Dimensional Finite Element Analyses

2014 ◽  
Author(s):  
Francis H. Ku ◽  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Steel Pipe ◽  
3D Analysis ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Stainless Steel Pipe

Two-dimensional (2D) and three-dimensional (3D) weld-induced residual stress finite element analyses have been performed for 2-inch Schedule 80 Type-304 stainless steel pipe sections joined by a multi-layer segmented-bead pipe weld. The analyses investigate the similarities and differences between the two modeling approaches in terms of residual stresses and axial shrinkage induced by the pipe weld. The 2D analyses are of axisymmetric behavior and evaluate two different pipe end constraints, namely fixed-fixed and fixed-free, while the 3D analysis approximates the non-axisymmetric segmented welding expected in production, with fixed-free pipe end constraints. Based on the results presented, the following conclusions can be drawn. The welding temperature contour results between the 2D and 3D analyses are very similar. Only the 3D analysis is capable of simulating the non-axisymmetric behavior of the segmented welding technique. The 2D analyses yield similar hoop residual stresses to the 3D analysis, and closely capture the maximum and minimum ID surface hoop residual stresses from the 3D analysis. The primary difference in ID surface residual stresses between the 2D fixed-fixed and 2D fixed-free constraints cases is the higher tensile axial stresses in the pipe outside of the weld region. The 2D analyses under-predict the maximum axial residual stress compared to the 3D analysis. The 2D ID surface residual stress results tend to bound the averaged 3D results. 2D axisymmetric modeling tends to significantly under-predict weld shrinkage. Axial weld shrinkage from 3D modeling is of the same magnitude as values measured in the laboratory on a prototypic mockup.

Measurement of the residual stresses in a stainless steel pipe girth weld containing long and short repairs

2005 ◽  
Vol 82 (4) ◽  
pp. 299-310 ◽  
Author(s):  
P.J. Bouchard ◽  
D. George ◽  
J.R. Santisteban ◽  
G. Bruno ◽  
M. Dutta ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Steel Pipe ◽  
Stainless Steel Pipe

The Measurement and Modelling of Residual Stresses in a Stainless Steel Pipe Girth Weld

2008 ◽  
Author(s):  
K. Ogawa ◽  
L. O. Chidwick ◽  
E. J. Kingston ◽  
R. Dennis ◽  
D. Bray ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Outer Surface ◽  
Mixed Mode ◽  
Steel Pipe ◽  
Outer Diameter ◽  
Hardening Model ◽  
Inner Surface ◽  
Stainless Steel Pipe

This paper presents results from a program of residual stress measurements and modelling carried out for a pipe girth weld of 369 mm outer diameter and 40 mm thickness. The component consisted of two 316 stainless steel pipe sections joined together using a “single-V” nickel base alloy (alloy 82) weld. The residual stresses were measured using the Deep-Hole Drilling (DHD) technique and modelled using ABAQUS. Biaxial, through-thickness residual stresses were measured through the weld centreline at a total of 6 different locations around the component. At three of the measurement locations the DHD process was carried out from the outer surface of the component with the remaining three, one of which coinciding with the weld start/stop position, carried out from the inner surface of the component. The differences in DHD process application (i.e. outer-to-inner or inner-to-outer) was carried out as a sub-objective to investigate the sequence of residual stress relaxation and its influence on the measured results. Good measurement repeatability was found between all locations. The hoop residual stresses were tensile at the outer surface, increasing to a maximum of 350 MPa at 10 mm depth, then decreasing to a minimum of −325 MPa at a depth of 34 mm, before increasing again towards the inner surface. The axial residual stresses were found to be similar in profile to the hoop residual stresses albeit lower in absolute magnitude by roughly 100 MPa. For this component it was found that the hoop residual stresses showed an influence of process direction, whereas for the axial residual stresses no influence was found. The modelling of the residual stresses generated was undertaken using a 2D axisymmetric finite element analysis containing 25 discrete weld beads. Each of the 25 weld beads were analysed sequentially using the following stages: heat source modelling, thermal analysis, elastic-plastic mechanical analysis. The sensitivity of the residual stresses generated with respect to the material hardening model used was investigated (i.e. kinematic, isotropic and mixed mode – kinematic/isotropic). Generally, the isotropic hardening model produces the highest predictions, the kinematic hardening model produces the lowest predictions with the mixed mode model lying in-between. Good agreement was found between the measured and modelled residual stresses. The main discrepancy existed in the hoop direction with the modelled residual stresses being the most tensile by roughly 200 MPa at depths within 15 mm of the outer surface of the pipe.

Surface melting technique of small diameter stainless steel pipe by means of yttrium aluminium garnet laser

1994 ◽  
Vol 153 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Fujito Katahira ◽  
Kenji Hirano ◽  
Yasuhiro Tanaka ◽  
Kazuo Yoshida ◽  
Munetaka Kuribayashi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Small Diameter ◽  
Surface Melting ◽  
Steel Pipe ◽  
Yttrium Aluminium Garnet ◽  
Yttrium Aluminium ◽  
Melting Technique ◽  
Stainless Steel Pipe ◽  
Yttrium Aluminium Garnet Laser
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