Residual Stress Engineering in Fatigue Resistant Welds

2013 ◽  
Vol 768-769 ◽  
pp. 613-619
Author(s):  
Majid Farajian ◽  
Zuheir Barsoum ◽  
Arne Kromm
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Body Of Knowledge ◽  
Fatigue Design ◽  
Welding Technology ◽  
Stress Engineering ◽  
Solid Foundation ◽  
Stress States ◽  
The Many ◽  
Quantitative Consideration

The developments in the field of residual stress determination during the last decades have contributed to a better understanding of the origins and sources of residual stresses in different engineering disciplines. The many investigations concerning the behavior of residual stresses under mechanical loading have also provided a solid foundation to clarify the important aspects of residual stresses and fatigue. The question that arises now is if this available body of knowledge is being used effectively in the field of welding technology to design and construct structures with better fatigue performances. In this paper the necessity of the development of the concept residual stress engineering for welds in which wanted residual stress states are tailored for specific cases by appropriate means will be discussed. The possibilities of the quantitative consideration of the benefits in the fatigue design codes will be presented in a practical example.

Influence of Initial and Welding Residual Stresses on Low Cycle Fatigue and Ratcheting Response Simulations of Elbows

2017 ◽  
Author(s):  
Nazrul Islam ◽  
Tasnim Hassan
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Low Cycle Fatigue ◽  
Simulation Models ◽  
Cycle Fatigue ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Girth Welding ◽  
Stress States ◽  
Welding Processes

Earlier studies [1] showed that the ANSYS software package customized with an advanced rate-independent constitutive model was unable to simulate some of the low-cycle fatigue responses of elbow components. Hence, simulations are performed to investigate the influence of manufacturing and welding residual stresses on elbow low-cycle fatigue responses. The sequentially coupled thermo-mechanical finite element analysis is performed to determine the initial residual stress states in elbows due to the elbow manufacturing processes and welding of elbows to straight pipes. Real-time girth-welding processes are taken into account to simulate the welding induced residual stress field. Incorporating these initial residual stresses in the computations, low-cycle fatigue and strain ratcheting responses are simulated by ANSYS. The simulation responses demonstrate that the influence of manufacturing and welding residual stresses in elbows on its low-cycle fatigue responses is negligible. Hence, the question remains what is missing in the simulation models that some of the elbow low-cycle fatigue responses cannot be simulated.

Residual Stress in Tools and Components in Case of Thermo-Mechanical Metal Forming Processes

2011 ◽  
Vol 681 ◽  
pp. 340-345 ◽  
Author(s):  
Alexander Grüning ◽  
Markus Lebsanft ◽  
Berthold Scholtes
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Process Parameters ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Manufacturing Operations ◽  
Challenging Tasks ◽  
Steel Aisi ◽  
Stress States ◽  
Adapted Process

Residual stresses play a key role in thermo-mechanically coupled forming processes for industrial mass production. They are an unavoidable consequence of the alternating inhomogeneous fields of temperature and mechanical stress developing in tools and components dependent on the process parameters applied. Because of their influence on the behavior of the components produced, a great interest exists to get reliable information about origin and distribution of the relevant residual stress fields and to understand the basic principles of their formation. In this paper the development of residual stress in tools (steel AISI H11) used for the thermo-mechanical forming operation of cylindrical flange shafts (steel SAE 6150) is outlined. The loading situation of the tool is simulated by thermal fatigue tests, providing information about cyclic stress and plastic deformation during the manufacturing process. Furthermore the residual stress states of the flange shafts manufactured are presented and discussed. Chip forming manufacturing operations are challenging tasks and tensile residual stresses can be avoided using adapted process parameters.

X-Ray Diffraction Measurements of Residual Stress Induced by Surface Compressing Methods

2012 ◽  
Vol 729 ◽  
pp. 199-204 ◽  
Author(s):  
Dávid Cseh ◽  
Valéria Mertinger
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Surface Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardened Alloy ◽  
Compressive Stresses ◽  
Machine Parts ◽  
Stress States ◽  
Operational Behaviour

Residual stresses have a fundamental effect on the operational behaviour and lifetime of industrial products. The fatigue resistance of machine parts can be increased by introducing residual compressive stresses into the surface region. For certain machine parts especially in the vehicle industry the residual stress is strongly demanded by the quality control. For this reason, measuring the stress accurately is becoming increasingly important. The Almen test, which only gives a qualitative result, is widely used in the industry. Shot peening and rolling are methods which are suitable for creating elastic residual stresses. This paper examines the technologies used by Rába Futómű Nyrt. to increase the lifetime by means of residual stress. We performed analysis of the residual stress of samples shot peened the same way but under different heat treatment states. We compared the residual stress values of burnished and hardened shaft joints, and the residual stress states of gear made of hardened alloy, comparing the carbonized ones to ones which were shot peened under small intensity.

Residual Stresses in Steel-Titanium Composite Manufactured by Explosive Welding

2012 ◽  
Vol 726 ◽  
pp. 125-132 ◽  
Author(s):  
Aleksander Karolczuk ◽  
Krzysztof Kluger ◽  
Mateusz Kowalski ◽  
Fabian Żok ◽  
Grzegorz Robak
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Residual Stresses ◽  
Hole Drilling ◽  
Element Analysis ◽  
Welded Steel ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Before And After ◽  
Stress States

The main aim of the paper is determination of residual stresses in explosively welded steel-titanium bimetal. The analysis considers two bimetallic specimens: before and after the heat treatment. In residual stress determination the hole drilling method along with finite element analysis were applied. The results show different residual stress states depending on the heat treatment. The obtained results are confirmed by thermal stress calculation.

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

2016 ◽  
Author(s):  
Yao Ren ◽  
Anna Paradowska ◽  
Bin Wang ◽  
Elvin Eren
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Residual Stresses ◽  
Outer Surface ◽  
Post Weld Heat Treatment ◽  
Stress Profiles ◽  
Stress States ◽  
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. Two pipe spools were fabricated using identical pipeline production procedures for manufacturing multi-pass narrow gap welds. Non-destructive neutron diffraction strain scanning was carried out on girth welded pipe spools and stress-free comb samples and also thin slices for the determination of 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 of two pipe spools (in the as-welded condition) were measured through the thickness in the weld material and adjacent parent metal starting from the weld toe. Three line-scans were completed 3mm below outer surface, at mid thickness and 3mm above the inner surface. PWHT was adopted for stress relaxation; 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 were measured after PWHT at exactly the same locations as those used for the as-welded condition. Residual stress states of the two 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 (3mm 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 states of the two pipe spools measured in the 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.

scholarly journals On the Behavior of Mechanical Stress Fields at Indentation of Materials with Residual Stresses

2021 ◽  
Author(s):  
Per-Lennart Larsson
Keyword(s):  
Residual Stresses ◽  
Contact Region ◽  
Empirical Relations ◽  
Solid Foundation ◽  
The Subject ◽  
Sharp Indentation ◽  
Stress States ◽  
Indentation Problem ◽  
Semi Empirical ◽  
Compressive Residual Stresses

AbstractIt is an obvious fact that residual stresses can have a detrimental effect on the mechanical integrity of structures. Measuring such stresses can often be a tedious task and for that reason sharp indentation testing has been proposed as an alternative for this purpose. Correlation between global indentation properties and residual stresses has been studied quite frequently, and a solid foundation has been laid down concerning this issue. Empirical, or semi-empirical, relations have been proposed yielding results of quite good accuracy. Further progress and mechanical understanding regarding this matter will require a more in-depth understanding of the field variables at this particular indentation problem and this is the subject of the present study. In doing so, finite element simulations are performed of sharp indentation of materials with and without residual stresses. Classical Mises plasticity and conical indentation are considered. The main conclusion from this study is that the development of stresses in materials with high or medium-sized compressive residual stresses differs substantially from a situation with tensile residual stresses, both as regards the level of elastic deformation in the contact region and the sensitivity of such stresses. Any attempt to include such stress states in a general correlation effort of indentation quantities is therefore highly unlikely to be successful.

Hochdynamisches Festwalzwerkzeug/New approaches to an innovative surface treatment of functional components – Highly dynamic deep rolling tool

2021 ◽  
Vol 111 (11-12) ◽  
pp. 851-856
Author(s):  
Vannila Prasanthan ◽  
Berend Denkena ◽  
Bernd Breidenstein ◽  
Alexander Krödel-Worbes ◽  
Oliver Maiß
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Surface Treatment ◽  
Deep Rolling ◽  
New Approaches ◽  
Stress States ◽  
Functional Components ◽  
Compressive Residual Stresses

Das Festwalzen ist ein etabliertes Verfahren, um gezielt Druckeigenspannungen in der Bauteilrandzone einzustellen. Aktuell existieren keine Werkzeuge, die lokal hochaufgelöst unterschiedliche Eigenspannungen erzeugen. Mit der Entwicklung eines hochdynamischen Festwalzwerkzeugs lassen sich lokal unterschiedliche Eigenspannungszustände belastungsangepasst einstellen. Die hierfür notwendigen Anforderungen werden mittels Analogieuntersuchungen identifiziert. Darauf basierend wird ein Konzept für das Werkzeug erstellt und konstruktiv umgesetzt.   Deep rolling is a well-established process to induce compressive residual stresses into the subsurface of a component. Currently, there are no rolling tools that generate different residual stresses with high local resolution. With the development of a highly dynamic deep rolling tool, locally varying residual stress states can be adjusted to the load. The necessary requirements for this are identified by means of analogy studies. Based on this, a concept for the tool is developed and implemented constructively.

About the Effects of Residual Stress States Coming from Manufacturing Processes on the Behaviour of Riveted Joints

2008 ◽  
Vol 385-387 ◽  
pp. 25-28 ◽  
Author(s):  
Francesco Caputo ◽  
Giuseppe Lamanna ◽  
Alessandro Soprano
Keyword(s):  
Residual Stress ◽  
Failure Modes ◽  
Pressure Effects ◽  
Load Pressure ◽  
Aerospace Applications ◽  
Joint Characteristics ◽  
Riveted Joints ◽  
Stress States ◽  
The Many ◽  
Operational Behaviour

A very large number of variables affect the response of bolted or riveted joints typically used in aerospace applications: geometry of the joint, characteristics of the sheets, friction between sheets, geometry of head and kind of fastener, amplitude of clearance before assembly, mounting axial load, pressure effects after manufacture. It must be also recalled that these parameters influence the many failure modes existing for such joints, among which a relevant importance is attributed to bearing. The present paper deals with the study of the influence of assembly parameters on the joint operational behaviour and in particular with the analysis, performed through numerical simulations, of the influence of the residual stress-strain state coming from the riveting operation on the bearing resistance of an aluminium alloy joint. This work has been developed within the FP6 research project called MUSCA (Non linear static multiscale analysis of large aero-structures).

Generation and Determination of Compressive Residual Stresses of Short Penetration Depths

2013 ◽  
Vol 768-769 ◽  
pp. 580-586 ◽  
Author(s):  
Regina Weingärtner ◽  
Jürgen Hoffmeister ◽  
Volker Schulze
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Fatigue Limit ◽  
Electrochemical Machining ◽  
Beneficial Effects ◽  
Integral Width ◽  
High Gradients ◽  
Stress States ◽  
Penetration Depths

Generating compressive residual stress states with high gradients and low penetration depths offers high capability regarding increase of fatigue limit of parts. In this work the determination of such specific residual stress distributions by using X-ray diffraction and a little material removal is introduced. Measurements are compared using two interference peaks of different penetration depths, at which confocal microscopy enables high accuracy in determination of the step sizes in electrochemical machining. Furthermore the realisation of these states by two different peening processes using micro blasting media is described. The suitability of the processes micro peening and ultrasonic wet peening as surface treatment methods to improve fatigue limit are shown. Micro peening is based on the shot peening principle with small shots and ultrasonic wet peening on the acceleration of small blasting particles by cavitation. The investigations were conducted at AISI 4140 in a quenched and tempered state. Besides the residual stresses and the integral width of interference peaks as well as the depth distributions, the surface topography was examined. The beneficial effects of these conditions on the fatigue limit in bending tests are described.

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