Download or read book Improving the Fatigue Life of High Strength Steel Welded Structures by Post Weld Treatments and Specific Filler Material FATWELDHSS written by and published by . This book was released on 2015 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the FATWELDHSS project was to study post-weld treatment techniques and their effect on the fatigue life of MAG welded attachments in High Strength Steel (HSS). Fatigue cracks in steel structures often occur at welded joints, where stress concentrations due to the joint geometry and tensile residual stresses are relatively high. Fatigue life improvement techniques, which rely on improving the stress field and/or the surface geometry around the welded joints, are generally known to be beneficial. Therefore, within the framework of this project, the following were examined: diode laser weld toe re-melting; High Frequency Mechanical Impact (HFMI) treatment; Low Transformation Temperature (LTT) filler wires Laser diode re-melting was used to improve the surface profile at the weld toe and thus reduce stress concentrations. HFMI treatment involving high frequency hammering of the weld toe is another technique that can produce a smooth weld toe profile but, more significantly, which also can introduce compressive residual stresses. Lastly, two new LTT filler wires were developed within the project as these can decrease or even remove tensile residual stresses resulting from weld zone shrinkage. An extensive fatigue testing programme was set up to establish the levels of improvement in the fatigue lives of the welded attachments achieved by application of the selected improvement techniques. Furthermore, two industrial demonstrators were selected that could show the project achievements in terms of facilitating the introduction of high strength steels by overcoming the limitations posed by the fatigue properties of the welded joints. In addition, modelling tools were developed to predict the residual stresses at the welded joint. Finally, practical guidelines were developed for enhancing the fatigue strength of HSS welded structures.
Download or read book Fatigue Performance of Welded High Strength Steels written by Welding Institute and published by . This book was released on 1974 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Weld detail fatigue life improvement techniques written by K. J. Kirkhope and published by . This book was released on 1996 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracks in steel ships often occur at welded joints where stress concentrations due to the joint geometry are relatively high and the fatigue strength of the weld is reduced in comparison to that of the base metal. This becomes more critical in ships built of High Strength Steels (HSS) because the fatigue strength of steel in the a welded condition does not increase in proportion to the yield or tensile strength. In many cases, the fatigue performance of severely loaded details can be improved by employing good detail design practices, for example by upgrading the welded detail class to one having a higher fatigue strength. In some cases, however, there may be no better alternatives to the detail in question and modification of the detail may not be practicable. As an alternative to strengthening the structure at a considerable increase in costs, procedures which reduce the severity of the stress concentration at the weld, remove imperfections, and/or introduce local compressive stresses at the weld can be used for improvement of the fatigue life. Similarly, these fatigue improvement techniques can be applied as remedial measures to extend the fatigue life of critical welds that have failed prematurely and have been repaired. To date, weld fatigue life improvement techniques have been successfully applied in several industries. While there has been increasing interest in the application of fatigue life improvement techniques to ship structures, at present there is a lack of guidance on the use of such techniques for design, construction and repair. Hence the key elements of this project were to compile available data on fatigue life improvement techniques, assess the feasibility and practicality for their application to ship details, identify gaps in the technology, and finally to recommend design, construction and repair requirements.
Download or read book Fatigue Strength of Welded Structures written by Kenneth George Richards and published by Woodhead Publishing Limited. This book was released on 1969 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recommendations for Fatigue Design of Welded Joints and Components written by A. F. Hobbacher and published by Springer. This book was released on 2015-12-23 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a basis for the design and analysis of welded components that are subjected to fluctuating forces, to avoid failure by fatigue. It is also a valuable resource for those on boards or commissions who are establishing fatigue design codes. For maximum benefit, readers should already have a working knowledge of the basics of fatigue and fracture mechanics. The purpose of designing a structure taking into consideration the limit state for fatigue damage is to ensure that the performance is satisfactory during the design life and that the survival probability is acceptable. The latter is achieved by the use of appropriate partial safety factors. This document has been prepared as the result of an initiative by Commissions XIII and XV of the International Institute of Welding (IIW).
Download or read book Improving the Fatigue Performance of Welded Stainless Steels written by and published by . This book was released on 2007 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: As with C-Mn steels, fillet welds in stainless steels can display low fatigue strengths. Therefore, possible ways of improving their fatigue performance were investigated, by choice of welding process or the application of a post-weld improvement technique. Three types of fillet welded specimen were made from three stainless steels, namely 10 mm thick 304L austenitic and higher strength S31803 duplex and 3 mm thick high-strength Cr-Mn austenitic steel. One aim was to show that the higher strength steels gained more benefit from an improvement technique. The basic test series were MAG welded, but TIG and powder plasma arc welds (PPAW) were included to investigate possible improved fatigue performance from these welding processes. In addition, four weld toe improvement techniques were applied, namely weld profile improvement by grinding or re-melting the weld toe with a TIG or plasma torch (TIG or plasma dressing) and the introduction of compressive residual stress by ultrasonic impact treatment (UIT). The specimens were fatigue tested axially at R = 0.1 or under high tensile mean stress conditions. Most tests were performed in air under constant amplitude loading, but toe ground and plasma dressed specimens were also tested in 3 % NaCl solution, while some TIG dressed and UIT specimens were tested under variable amplitude loading. Many testing conditions were selected specifically to investigate features of actual service operation that might reduce the benefit of an improvement technique. The TIG and PPA welds did not produce better fatigue performance than MAG welds. However, all the improvement techniques were beneficial, the improvement increasing with decrease in applied stress range. The basic level of improvement in fatigue strength in air for R = 0.1 was 30 %. However, this could be greater; especially the increase in fatigue limit, or less, depending on the method of application of the improvement technique, the operating conditions and to some extent the original weld profile. Thus, success with the re-melting techniques depended on the achievement of a generous weld toe radius, while UIT of a poor profile weld could leave flaws in the deformed weld toe material and actually reduce the fatigue performance. Grinding was the most tolerant technique, but it was less suitable for the 3 mm Cr-Mn austenitic steel because of the significant loss of thickness. The benefit of the weld profile improvement techniques was reduced in 3 % NaCl solution but not under high tensile mean stress or variable amplitude loading. However, UIT, which relies on the presence of compressive residual stress, was of little benefit under such conditions. There was no fundamental difference in the effect of an improvement technique when applied to the low and high-strength steels, except that the higher strength duplex and Cr-Mn austenitic steels could sustain stresses above the yield strength of Type 304L austenitic. However, ground or dressed duplex welds performed slightly better than the austenitic steel in 3 % NaCl solution.
Download or read book Fatigue Design of Welded Joints and Components written by A Hobbacher and published by Woodhead Publishing. This book was released on 1996-10-31 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: These recommendations present general methods for the assessment of fatigue damage in welded components, which may affect the limit states of a structure, such as ultimate limit state and serviceability limited state. Fatigue resistance data is given for welded components made of wrought or extruded products of ferritic/pearlitic or banitic structural steels up to fy = 700 Mpa and of aluminium alloys commonly used for welded structures.
Download or read book Bibliography on the Fatigue of Welded Structures written by and published by . This book was released on 1970 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Techniques for Improving the Fatigue Strength of Welded Structures written by J. D. Harrison and published by . This book was released on 1965 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Life Analyses of Welded Structures written by Naman Recho and published by . This book was released on 2005* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methods of Fatigue Life Improvement for Welded Joints in Medium and High Strength Steels written by S. Manteghi and published by . This book was released on 1998 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture Mechanics Fatigue Life Assessment of Welded Joints Under Ultrasonic Impact Treatment written by Mehrdad Sarafrazi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Welding joints are the most used joining method to fabricate engineering structures due to their low cost, structural strength, and geometric flexibility. Irregular geometries, micro cracks, defects, high stress concentration and tensile residual stresses are some of the results of a highly metallurgical process considered as welding. Thus, an important subject of growing concern in product design is to consider some of the critical factors caused from the weld process including high tensile residual stresses and stress concentrations to properly evaluate the fatigue life of the structures. Lightweight design of welded steel and aluminum structures in cyclic service requires the use of post-treatment approaches like Ultrasonic Impact Treatment (UIT). In this thesis, an evaluation of fatigue tests carried out recently on welded specimens exposed to UIT under the effect of the constant amplitude (CA) loading on the fatigue strength is described. First, the effects of the various fatigue damage parameters on the as-welded (AW) condition and the impact treated welds are described in the literature review. Furthermore, fatigue test data have been taken from literature for both conditions under CA loading for several different stress ranges for each material. Following the tests, residual stress distributions below the weld toe surface have been specified by x-ray diffraction of untested specimens. More importantly, the test data obtained from the literature were analyzed through out the thesis and were used to define input parameter values for fracture mechanics analyses of the welded joint specimens. After that, the crack growth assessment of welded structures is provided. For comparison purposes, both Walker and Forman fatigue crack growth models are thoroughly reviewed and their advantages as invaluable tools for predicting the effects of UIT on fatigue performance for welded joints are examined. Subsequently, the benefit of the models in predicting fatigue crack growth behaviors for nine distinct materials are examined and the effects of the various material strength parameters on the impact treatment performance are assessed. Then, fatigue crack propagation life of the materials is displayed. In the end, the crack shape evolution of the materials is depicted. In conclusion, the outcomes of this investigation accompanied by proposed future work are mentioned.
Download or read book P 1060 Schwingfestigkeitsverbesserung hochfester Schwei verbindungen mit Hilfe neuartiger LTT Zusatzwerkstoffe written by and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Weldments on the Fatigue Strength of Steel Beams written by John W. Fisher and published by . This book was released on 1963 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue of Welded Steel Structures written by W. H. Munse and published by . This book was released on 1964 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improvement of Fatigue Strength in Welded High Tensile Strength Steel by Toe Treatment written by Mitsugu Hanzawa and published by . This book was released on 1977 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Lack of Penetration on Fatigue Resistance of High strength Structural Steel Welds written by Y. Tobe and published by . This book was released on 1977 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zero-to-tension fatigue tests were carried out on double-V butt welds of ASTM A514 steel plate, 20 mm in thickness, which contained full-length lack of penetration (LOP) defects. The fatigue crack initiation and propagation portions of the specimens' fatigue lives were experimentally separated. Compression-to-tension fatigue tests were carried out on prime base plate, as-welded sound joints, and reinforcement-removed welds to experimentally determine the fatigue strength reduction factor (Kf) of the LOP defects. LOP defects as small as 0.5 mm wide had a profound effect on fatigue life. The fatigue crack initiation life was found to be short-only 10 percent of the total life-and could be predicted using fatigue crack initiation concepts. The use of KF(max), the maximum possible fatigue strength reduction factor, was found to be appropriate. In a separate substudy, the fatigue resistance of ASTM A514 butt-welded joints containing clustered porosity was determined. (Author).
