Nondestructive residual-stress measurement on the inside surface of stainless-steel pipe weldments

1984 ◽  
Vol 24 (2) ◽  
pp. 162-168 ◽  
Author(s):  
C. O. Ruud ◽  
P. S. DiMascio ◽  
D. M. Melcher
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Inside Surface ◽  
Steel Pipe ◽  
Stainless Steel Pipe

Analysis of Eddy-Current Measurement System for Residual Stress Assessment in Stainless Steel Grade 304

2015 ◽  
Vol 659 ◽  
pp. 623-627 ◽  
Author(s):  
Cherdpong Jomdecha ◽  
Isaratat Phung-On
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Eddy Current ◽  
Measurement System ◽  
System Analysis ◽  
Stress Measurement ◽  
Steel Grade ◽  
Current Measurement ◽  
Residual Stress Measurement ◽  
Stress Assessment

The objective of this paper is an analysis of statistical discreteness and measurement capability of an eddy-current measurement system for residual stress assessment in stainless steel Grade 304 (SS304). Cylindrical specimens with 50 mm in diameter and 12 mm thickness were prepared to generate residual stress by Resistance Spot Welding at which the welding currents were set at 12, 14, and 16 kA. The eddy-current measurement system was including a probe with frequency range of 0.1 to 3 MHz and an eddy current flaw detector. They were performed by contacting the probe on the specimen. The measurements were performed particularly in the vicinity of heat affected zone (HAZ). In order to determine the results of the residual stress measurement, the calibration curves between static tensile stress and eddy current impedance at various frequencies were accomplished. The Measurement System Analysis (MSA) was utilized to evaluate the changed eddy-current probe impedance from residual stress. The results showed that using eddy current technique at 1 MHz for residual stress measurement was the most efficient. It can be achieved the Gauge Repeatability & Reproducibility %GR&R at 16.61479 and Number of Distinct Categories (NDC) at 8. As applied on actual butt welded joint, it could yield the uncertainty of ± 58 MPa at 95 % (UISO).

Numerical Simulation of Residual Stress in Multi-Pass Butt-Welded Stainless Steel Pipe

2009 ◽  
Author(s):  
S. Kasa ◽  
M. Mouri ◽  
M. Tsunori ◽  
D. Takakura
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Three Dimensional ◽  
Structural Response ◽  
Welding Residual Stress ◽  
Steel Pipe ◽  
Inelastic Behavior ◽  
Axisymmetric Model ◽  
Stiffness Method ◽  
Stainless Steel Pipe

It is necessary to obtain an accurate welding residual stress distribution for the evaluation of stress corrosion cracking (SCC) behavior. However, a welding residual stress simulation for pipes is often performed by a two dimensional axisymmetric model because this type of simulation requires significant time to analyze the complicated inelastic behavior. This approximation deteriorates the modeling accuracy since the welding heat input and the structural response are approximated by axisymmetric responses although they are originally three dimensional. The authors propose “a virtual additional stiffness method” in order to improve the accuracy of the axisymmetric model. With this method, the difference between the axisymmetric model and a three dimensional behavior was greatly reduced. The virtual additional stiffness method was used to reproduce three dimensional constraints that were not taken into account in the axisymmetric model. In the case of the axisymmetric model, an unrealistic large thermal expansion was observed because of simultaneous heating along a hoop direction of the whole pipe. In order to compensate this unrealistic deformation, a virtual additional stiffness was added in axial and radial directions on the axisymmetric model. This stiffness was added by using spring elements whose positions and spring constants were determined by comparing the two and three dimensional models. Results obtained by this new method in the multi-pass butt-welded stainless steel pipe were in very good agreement with measurements of the mock-up specimens.

Post Welding Heat Treatment Simulation in Welded Stainless Steel Pipe and Comparison with Experiment

2009 ◽  
Vol 83-86 ◽  
pp. 237-243
Author(s):  
Mohammad Sedighi ◽  
B. Davoodi
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Distribution ◽  
Numerical Models ◽  
Welding Process ◽  
Steel Pipe ◽  
Hole Drilling ◽  
Distribution Data ◽  
Stainless Steel Pipe

Due to the intense concentration of heat in the welding process, residual stresses are produced in the specimen. One of the most effective ways to relief welding stress is Post Welding Heat Treatment (PWHT). In this paper, finite element method is employed to model and analyze PWHT for two pass butt-welded SUS304 stainless steel pipe. In this simulation, firstly, the welding process has been modeled. Then the stress distribution of the specimen has been transferred to a second analysis for stress relaxation modeling. Norton law is used to investigate creep in stress relief process. Experimental tests are also carried out to verify the effectiveness of the proposed numerical models. The hole drilling method is used to measure the stress distribution in the specimen. The residual stress distribution data before and after PWHT are compared to investigate the effect of heat treatment on residual stress. Based on the modeling and experimental results, the tensile and compressive stresses distributions have been reduced. They are in a reasonable agreement with each other and prove the capability of the proposed modeling technique to simulate PWHT.

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.

Curvature-based residual stress measurement for ion-implanted stainless-steel sheet

Vacuum ◽  
2004 ◽  
Vol 75 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Q Wang ◽  
H Ishikawa ◽  
S Nakano ◽  
H Ogiso ◽  
J Akedo
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Steel Sheet ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Stainless Steel Sheet ◽  
Ion Implanted
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