Comparison of Neutron Diffraction Measurements of Residual Stress of Steel Butt Welds With Current Fitness-for-Purpose Assessments

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Anna M. Paradowska ◽  
John W. H. Price ◽  
Trevor R. Finlayson ◽  
Ronald B. Rogge ◽  
Ronald L. Donaberger ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Stress Distributions ◽  
Fitness For Purpose ◽  
Full Penetration ◽  
Heat Treated ◽  
Strain Stress ◽  
Steel Welds ◽  
Neutron Diffraction Technique ◽  
Weld Heat

In this research, the neutron diffraction technique was used to investigate the residual stress distributions in constrained carbon steel welds. Two full penetration welds were studied using (a) the stringer bead and (b) the temper bead weld techniques in 25 mm thick plate. The welds were not post-weld heat treated. The focus of the measurements is on the values of the subsurface and through-thickness strain/stress variation near the middle of the weld and the toe. The experimental results showed that both processes had high residual stresses particularly through the thickness. The measurements were compared with current fitness-for-purpose approaches, such as BS7910 and R6. It was found that the residual stress distribution in the temper bead welded specimen was not as favorable as suspected and post-weld heat treatment should be recommended to reduce residual tensile stresses in this type of steel welds.

Comparison of Neutron Diffraction Residual Stress Measurements of Steel Welded Repairs With Current Fitness-for-Purpose Assessments

2008 ◽  
Author(s):  
Anna M. Paradowska ◽  
John W. H. Price ◽  
Trevor R. Finlayson ◽  
Ronald B. Rogge ◽  
Ronald L. Donaberger ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Thick Plate ◽  
Stress Distributions ◽  
Fitness For Purpose ◽  
Stress Variation ◽  
Full Penetration ◽  
Heat Treated ◽  
Strain Stress ◽  
Neutron Diffraction Technique

In this research the neutron diffraction technique was used to investigate the residual stress distributions in carbon steel components with weld repairs. Two full penetration weld repairs were studied using a) the stringer bead and b) the temper bead weld techniques in 25 mm thick plate. The welds were not post weld heat treated. The focus of the measurements is on the values of the sub-surface and through-thickness strain/stress variation near the middle of the weld and the toe. The experimental results showed that both processes had high residual stresses particularly through the thickness. The measurements were compared with current fitness-for-purpose approaches, such as BS7910 and R6 showing that these approaches underestimated and overestimated the stresses in various regions.

Neutron Diffraction Evaluation of Residual Stress for Several Welding Arrangements and Comparison With Fitness-for-Purpose Assessments

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Anna M. Pardowska ◽  
John W. H. Price ◽  
Raafat Ibrahim ◽  
Trevor R. Finlayson
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Assessment Procedure ◽  
Stress Distributions ◽  
Fitness For Purpose ◽  
Single Bead ◽  
Surface Measurements ◽  
Number Of Passes ◽  
Neutron Diffraction Technique ◽  
Level 2

In this research, the neutron diffraction technique was used to investigate and compare the residual stress characteristics in several weld arrangements. This research has focused on the effects on residual stress of restraint condition applied during welding, the start and end of the weld for a single bead, and increasing the number of passes. The measured residual stress distributions are normalized by the yield strength of the material and compared with distribution provided in fitness-for-purpose procedures. It is found that the current safety assessment procedure BS 7910 and R6 Level 1 significantly conservative for longitudinal stresses outside the weld and heat affected zone, and for transverse residual stress across the weldment for surface measurements. For a less conservative assessment, R6 Level 2 is recommended, however, even if this assessment is often conservative, in particular, for transverse residual stresses.

Neutron Diffraction Evaluation of Residual Stress for Several Welding Arrangements and Comparison With Fitness-for-Purpose Assessments

2006 ◽  
Author(s):  
Anna M. Paradowska ◽  
John W. H. Price ◽  
Raafat Ibrahim ◽  
Trevor Finlayson ◽  
Richard Blevins ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Assessment Procedure ◽  
Stress Distributions ◽  
Fitness For Purpose ◽  
Single Bead ◽  
Level 1 ◽  
Number Of Passes ◽  
Neutron Diffraction Technique ◽  
Level 2

In this research the neutron diffraction technique was used to investigate and compare the residual stress characteristics in a several weld arrangements. This research has focused on the effects on residual stress of: • restraint condition applied during welding, • the start and end of the weld for a single bead, and • increasing the number of passes. The measured residual stress distributions are normalized by the yield strength of the material and compared with distribution provided in fitness-for-purpose procedures. It is found that the current safety assessment procedure BS 7910 and R6 Level 1 are significantly conservative. For a less conservative assessment R6 Level 2 is recommended, however even this assessment is often conservative, in particular for transverse residual stresses.

scholarly journals SPR Characteristics Curve and Distribution of Residual Stress in Self-Piercing Riveted Joints of Steel Sheets

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Rezwanul Haque ◽  
Yat C. Wong ◽  
Anna Paradowska ◽  
Stuart Blacket ◽  
Yvonne Durandet
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Steel Sheet ◽  
Sheet Material ◽  
Stress Distributions ◽  
Steel Sheets ◽  
Riveted Joints ◽  
Lower Magnitude ◽  
Thick Joint ◽  
Neutron Diffraction Technique

Neutron diffraction was used to describe the residual stress distributions in self-piercing riveted (SPR) joints. The sheet material displayed a compressive residual stress near the joint, and the stress gradually became tensile in the sheet material far away from the joint. The stress in the rivet leg was lower in the thick joint of the softer steel sheet than in the thin joint of the harder steel sheet. This lower magnitude was attributed to the lower force gradient during the rivet flaring stage of the SPR process curve. This study shows how the residual stress results may be related to the physical occurrences that happened during joining, using the characteristics curve. The study also shows that neutron diffraction technique enabled a crack in the rivet tip to be detected which was not apparent from a cross-section.

Interpretation of residual stress distributions in previously loaded cracked beams

1992 ◽  
Vol 27 (2) ◽  
pp. 77-83 ◽  
Author(s):  
D J Smith ◽  
M A M Bourke ◽  
A P Hodgson ◽  
G A Webster ◽  
P J Webster
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Crack Tip ◽  
Stress Distributions ◽  
Element Analysis ◽  
Sampling Volume ◽  
Neutron Diffraction Technique ◽  
Good Agreement

The measurement and prediction of residual stress distributions in a fatigue pre-cracked and a plastically overloaded A533B steel beam are described. The residual stresses were obtained experimentally using the neutron diffraction technique. Finite element analysis was employed to predict the elastic-plastic response and residual stresses introduced after overloading. Comparison of the experimental results have been made with the finite element predictions (for both plane stress and strain conditions) averaged over the same sampling volume used to make the neutron diffraction measurements. It has been found that good agreement is achieved away from the near crack tip region. However, close to the crack tip the measured compressive residual stresses are significantly smaller than predicted. This difference is attributed to the A533B steel exhibiting a Bauschinger effect and yielding at a lower stress after a stress reversal.

Neutron Diffraction Studies of Residual Stress Distribution in the Vicinity of the Single Pass Fillet Steel Welds

2015 ◽  
Vol 732 ◽  
pp. 13-19
Author(s):  
Ľuboš Mráz ◽  
Leif Karlsson ◽  
Miroslav Vrána ◽  
Pavol Mikula
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Strain ◽  
Residual Stress Distribution ◽  
Filler Materials ◽  
Single Pass ◽  
Stress Measurements ◽  
Strain Stress ◽  
Steel Welds

In this contribution the results of residual strain/stress measurements performed on several single pass fillet steel welds which were carried out at different welding conditions, namely, with different filler materials are presented.

The Effectiveness of Cold Rolling for Residual Stress Reduction in Quenched 7050 Aluminium Alloy Forgings

2016 ◽  
Vol 716 ◽  
pp. 521-527 ◽  
Author(s):  
Ran Pan ◽  
Catrin Mair Davies ◽  
Wei Zhang ◽  
Zhusheng Shi ◽  
Thilo Pirling ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Cold Rolling ◽  
Stress Reduction ◽  
Stress Distributions ◽  
Effective Technique ◽  
The Core ◽  
Cold Rolled ◽  
Neutron Diffraction Technique

Residual stresses are often introduced into aluminum alloys through quenching processes performed to generate the required microstructure. Such residual stresses are known to be deleterious to the integrity of the component. Methods to mitigate residual stresses in quenched components are therefore of great importance. Cold rolling has been proposed as an effective technique to remove residual stresses in large components. In this work, the effectiveness of cold rolling in reducing the residual stresses in quenched blocks AA7050 has been quantified using the neutron diffraction technique. Neutron diffraction measurements have been performed on two blocks one quenched and the other quenched & cold rolled block. Comparing the residual stress distributions pre and post rolling it has been found that cold rolling almost eliminates the tensile residual stresses in the core of the block, however it generates large tensile residual stresses d in a shallow region near the surface of the block.

Design Optimisation of a Ferritic Ring Weld Specimen Using FE Modelling

2009 ◽  
Author(s):  
Christopher M. Gill ◽  
Paul Hurrell ◽  
John Francis ◽  
Mark Turski
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Finite Element Modelling ◽  
Post Weld Heat Treatment ◽  
Stress Fields ◽  
Element Modelling ◽  
Weld Heat

This paper describes the design optimisation of an SA508 ferritic steel ring weld specimen using FE modelling techniques. The aim was to experimentally and analytically study the effect of post weld heat treatment upon a triaxial residual stress field. Welding highly constrained geometries, such as those found in some pressure vessel joints, can lead to the formation of highly triaxial stress fields. It is thought that application of post weld heat treatments will not fully relax hydrostatic stress fields. Therefore a ferritic multi-pass ring weld specimen was designed and optimised, using 2D finite element modelling, to generate a high magnitude triaxial stress field. The specimen thickness and weld-prep geometry was optimised to produce a large hydrostatic stress field and still allow efficient use of neutron diffraction to measure the residual stress. This paper reports the development of the test specimen geometry and compares the results of welding FE analysis and neutron diffraction measurements. Welding residual stresses were experimentally determined using neutron diffraction; both before post weld heat treatment. Three dimensional moving heat source weld finite element modelling has been used to predict the residual stresses generated by the welding process used. Finite element modelling examined the effect of phase transformation upon the residual stress field produced by welding. The relaxation of welding stresses by creep during post weld heat treatment has also been modelled. Comparisons between the modelled and measured as-welded residual stress profiles are presented. This work allows discussion of the effect of post weld heat treatment of triaxial stress fields and determines if finite element modelling is capable of correctly predicting the stress relaxation.

Residual Stress Analysis Considering Phase Transformation and Transformation Plasticity for Heat-Treated Large Size Shaft

2016 ◽  
Vol 725 ◽  
pp. 647-652 ◽  
Author(s):  
Yusuke Yanagisawa ◽  
Yasuhiro Kishi ◽  
Katsuhiko Sasaki
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Air Cooling ◽  
Water Cooling ◽  
Stress Distributions ◽  
Transformation Plasticity ◽  
Large Size ◽  
Heat Treated ◽  
Good Agreement

The residual stress distributions of the forgings after both water-cooling and air-cooling were measured experimentally. The residual stress occurring during the heat-treatment was also simulated considering the phase transformation and the transformation plasticity. A comparison of the experiments with the simulations showed a good agreement. These results shows that the transformation plastic strain plays an important role in the heat treatment of large forged shafts.

Effect of post-weld heat treatment on thermal diffusivity in UNS S32304 duplex stainless steel welds

2017 ◽  
Vol 2 (88) ◽  
pp. 49-58
Author(s):  
E.G. Betini ◽  
C.S. Mucsi ◽  
T.S. Luz ◽  
M.T.D. Orlando ◽  
M-N. Avettand-Fènoël ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Thermal Diffusivity ◽  
Duplex Stainless Steel ◽  
Welding Process ◽  
Austenite Phase ◽  
Shielding Gas ◽  
Heat Treated ◽  
Steel Welds ◽  
Weld Heat

Purpose: The thermal diffusivity variation of UNS S32304 duplex stainless steel welds was studied after pulsed GTA welding autogenous process without filler addition. This property was measured in the transverse section of thin plates after welding process and post-heat treated at 750°C for 8 h followed by air-cooling. Design/methodology/approach: The present work reports measurements of thermal diffusivity using the laser-flash method. The thermal cycles of welding were acquired during welding by means of k-type thermocouples in regions near the weld joint. The used shielding gas was pure argon and 98% argon plus 2% of nitrogen. The temperature profiles were obtained using a digital data acquisition system. Findings: It was found an increase of thermal diffusivity after welding process and a decrease of these values after the heat treatment regarding the solidified weld pool zone, irrespective of the welding protection atmosphere. The microstructure was characterized and an increase of austenite phase in the solidified and heat-affected zones was observed for post-weld heat-treated samples. Research limitations/implications: It suggests more investigation and new measurements about the influence of the shielding gas variation on thermal diffusivity in the heat-affected zone. Practical implications: The nuclear industry, especially, requests alloys with high thermal stability in pipes for power generation systems and safe transportation equipment’s for radioactive material. Thus, the duplex stainless steel grades have improved this stability over standard grades and potentially increase the upper service temperature reliability of the equipment. Originality/value: After heat treatment, the welded plate with 98%Ar plus 2%N2 as shielding gas presented a thermal diffusivity closer to the as received sample. By means of 2%-nitrogen addition in shielding gas during GTAW welding of duplex stainless steel may facilitate austenite phase reformation, and then promotes stability on the thermal diffusivity of duplex stainless steels alloys.

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