scholarly journals Experimental Investigation of Vibration Stress Relief of A106 Steel Pipe T-Welded Fittings

2019 ◽  
Vol 25 (8) ◽  
pp. 52-61
Author(s):  
Hameed Dwech Lafta ◽  
Sarkawt Rostam ◽  
Fryad Jalal Mahmud ◽  
Ronya Osman Abdulrahman ◽  
Rebin Omer Ali ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Experimental Investigation ◽  
Residual Stresses ◽  
Vibration Frequency ◽  
Stress Relief ◽  
Steel Pipe ◽  
Pipe Fitting ◽  
Material Stability ◽  
Vibration Stress

This research examines the use of vibratory treatments to reduce residual stresses in small welded parts. In this experimental investigation, a post weld vibration treatment was applied to T- A106 steel pipe fitting specimens to study the effect of the treatment on the residual stress and the hardness of the material. The vibratory stress relief treatment was carried out at different vibration frequency. The results have demonstrated that post-weld vibratory stress relief of small size fittings is possible and residual stress may be relieved, and the treatment may be an alternative method for heat treatment especially when unchange in dimensions and material stability are required.  

Research on Vibration Stress Relief for Cured SU-8 Photoresist Layer

2015 ◽  
Vol 1094 ◽  
pp. 487-490
Author(s):  
Qun Feng Yang ◽  
Jian Yi Zheng ◽  
Jun Qing Wang ◽  
Xue Nan Zhao ◽  
Da Yin Wei ◽  
...  
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
Stress Relief ◽  
Excitation Current ◽  
Photoresist Layer ◽  
Before And After ◽  
Vibration Stress ◽  
Vibration Time ◽  
Vibration Parameters

The aim of this work is to reduce the residual stress in cured SU-8 Photoresist layer by vibration stress relief (VSR) method. The vibration device was designed according to the results of the ANSYS modal simulation, which was used for the thin film VSR. Meanwhile, some important influencing factors, such as the excitation current and the vibration time, have been discussed. The residual stress in the SU-8 layer was measured by profile method, and the values of residual stresses in the SU-8 layer before and after VSR were compared. The experimental results show that residual stress in SU-8 layer can be effectively eliminated or homogenized by VSR if the proper vibration parameters were chosen in the experiment.

scholarly journals Residual Stress State of X65 Pipeline Girth Welds Before and After Local and Furnace Post Weld Heat Treatment

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Yao Ren ◽  
Anna Paradowska ◽  
Bin Wang ◽  
Elvin Eren ◽  
Yin Jin Janin
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Residual Stresses ◽  
Outer Surface ◽  
Post Weld Heat Treatment ◽  
Pipe Length ◽  
Stress Profiles ◽  
Girth Welds ◽  
Welded Pipe ◽  
Weld Heat

This research investigated the effects of global (in other words, furnace-based) and local post weld heat treatment (PWHT) on residual stress (RS) relaxation in API 5L X65 pipe girth welds. All pipe spools were fabricated using identical pipeline production procedures for manufacturing multipass narrow gap welds. Nondestructive neutron diffraction (ND) strain scanning was carried out on girth welded pipe spools and strain-free comb samples for the determination of the lattice spacing. All residual stress measurements were carried out at the KOWARI strain scanning instrument at the Australian Nuclear Science and Technology Organization (ANSTO). Residual stresses were measured on two pipe spools in as-welded condition and two pipe spools after local and furnace PWHT. Measurements were conducted through the thickness in the weld material and adjacent parent metal starting from the weld toes. Besides, three line-scans along pipe length were made 3 mm below outer surface, at pipe wall midthickness, and 3 mm above the inner surface. PWHT was carried out for stress relief; one pipe was conventionally heat treated entirely in an enclosed furnace, and the other was locally heated by a flexible ceramic heating pad. Residual stresses measured after PWHT were at exactly the same locations as those in as-welded condition. Residual stress states of the pipe spools in as-welded condition and after PWHT were compared, and the results were presented in full stress maps. Additionally, through-thickness residual stress profiles and the results of one line scan (3 mm below outer surface) were compared with the respective residual stress profiles advised in British Standard BS 7910 “Guide to methods for assessing the acceptability of flaws in metallic structures” and the UK nuclear industry's R6 procedure. The residual stress profiles in as-welded condition were similar. With the given parameters, local PWHT has effectively reduced residual stresses in the pipe spool to such a level that it prompted the thought that local PWHT can be considered a substitute for global PWHT.

Finite Element Simulation Analysis on Residual Stress Relief of 7075 Aluminum Alloy Ring

2021 ◽  
Vol 1032 ◽  
pp. 135-140
Author(s):  
Shao Feng Wu ◽  
Xiang Sheng Gao ◽  
Xian Rang Zhang ◽  
Han Jun Gao
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Simulation Analysis ◽  
Material Model ◽  
Stress Relief ◽  
Isotropic Hardening ◽  
7075 Aluminum Alloy ◽  
Vibration Stress ◽  
Structural Parts ◽  
Creep Constitutive Model

Vibration stress relief (VSR) and thermal stress relief (TSR) are important method to eliminate the residual stress of structural parts. The thermal vibratory stress relief (TVSR) is a new method to decrease and homogenize the residual stress. Based on the stress relaxation tests and the equivalent vibration equation of modal analysis, the creep constitutive model and the bilinear isotropic hardening plasticity material model (BISO) are combined to establish the numerical simulation model of TVSR of 7075 aluminum alloy ring part. The simulation results show that four different initial blank residual stress levels are obtained after quenching process, and the residual stress elimination and homogenization effect of TSR and TVSR is better than that of VSR. TVSR has a better effect on both residual stress elimination and homogenization, and the residual stress relief rate can reach more than 20%.

Experimental Investigation of Residual Stresses after Heat Treatment and Grinding Processes in the Production of Ball Bearing Rings

2008 ◽  
Vol 571-572 ◽  
pp. 27-32 ◽  
Author(s):  
Volkan Güley ◽  
A. Erman Tekkaya ◽  
Turhan Savaş ◽  
Feridun Özhan
Keyword(s):  
Heat Treatment ◽  
Experimental Investigation ◽  
Residual Stresses ◽  
Process Parameters ◽  
Treatment Process ◽  
Ball Bearing ◽  
Grinding Process ◽  
Heat Treatment Process ◽  
Grinding Processes ◽  
Bearing Rings

Experimental investigation of residual stresses after heat treatment and grinding processes in the production of ball bearing rings has been carried out. The residual stresses were measured by X-ray diffraction method utilizing chromium radiation, which has an average penetration depth of 5 μm incident on 100Cr6 (AISI-E52100) ball bearing steel. The process parameters of heat treatment and grinding processes were varied so as to represent the extreme values that can be applied in the respective processes. Hardness and percent retained austenite limit the heat treatment process parameters; while roundness, surface roughness and form the grinding process. Tensile surface residual stresses on the raceway of ball bearing rings changes to compression after grinding in both circumferential and axial directions. In grinding relatively higher compressive stresses were measured in axial direction compared to the circumferential direction. This experimental investigation also showed that the influence of heat treatment process parameters on the magnitude and distribution of residual stresses survived even after grinding process; i.e. heat treatment and grinding processes cannot be evaluated independently in process design for favourable residual stresses.

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.

Residual Stress Relief in the Aluminium Alloy 7075

2017 ◽  
Vol 905 ◽  
pp. 31-39 ◽  
Author(s):  
Jeremy S. Robinson ◽  
Christopher E. Truman ◽  
Thilo Pirling ◽  
Tobias Panzner
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Stress Relief ◽  
Residual Stress Distribution ◽  
Cold Compression ◽  
Heat Treated ◽  
Minimum Residual

The residual stresses in heat treated 7075 aluminium alloy blocks have been characterised using two neutron diffraction strain scanning instruments. The influence of uniaxial cold compression (1-10%) on relieving the residual stress has been determined. Increasing the magnitude of cold compression from 1 to 10% has been shown to have a beneficial effect on the residual stress distribution by reducing the range between the maximum and minimum residual stresses. The effect of over aging 7075 on residual stress has also been characterised using neutron diffraction and this was found to reduce the residual stress by 25-40%. A relationship between {311} peaks widths and amount of cold compression was also observed.

Research on Vibration Stress Relief Based on FEM

2010 ◽  
Vol 42 ◽  
pp. 35-38
Author(s):  
Chun Mei Li ◽  
Feng Kui Cui
Keyword(s):  
Residual Stress ◽  
Finite Elements ◽  
Stress Distribution ◽  
Stress Relief ◽  
Residual Stress Distribution ◽  
Exciting Force ◽  
Finite Elements Method ◽  
Machining Process ◽  
Exciting Frequency ◽  
Vibration Stress

In order to improve VSR(Vibration Stress Relief) effect, finite elements method is applied to study VSR process factors. Simulation on moulding process, rough machining process and heat treatment are used to study the residual stress distribution of casting. The modal analysis is carried out to determine exciting frequency, exciting position and support position. Based on residual stress distribution, harmonic response analysis is applied to find relationship between dynamic stress and exciting force. Then the exciting force can be determined. The research results indicate that finite elements method can be used to determine VSR process parameters quickly and accurately.

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.

Relationship between the Microstructure of the Welded Steel Plates and the Efficiency of Vibration Stress Relief

2014 ◽  
Vol 941-944 ◽  
pp. 2062-2065
Author(s):  
Shu Qi Li ◽  
Hong Yuan Fang ◽  
Xue Song Liu ◽  
Wei Cui
Keyword(s):  
Residual Stress ◽  
Stress Relief ◽  
Steel Plates ◽  
Low Alloy Steels ◽  
Welded Steel ◽  
Welded Structures ◽  
Vibration Stress ◽  
Alloy Steels ◽  
The Difference ◽  
Main Factor

Welded components of low alloy steels are widely used in various applications. Stress reliving is very important to these welded structures. Vibration stress relief (VSR) is an relatively new method for this purpose. In this study, Q235 and Q345 steel plates were welded. Then they were treated by VSR. The microstructure of the welded lines were investigated and the residual stresses in two directions in these welded structures were measured. The difference of the efficiency of VSR on the two materials were investigate. It is found that, the decreasing amplitude of the residual stress in the Q235 welded structures significantly exceeded that in the Q345 welded structures. The grain size in the area near the weld lines is the main factor that affects the efficiency of the VSR treatment.

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