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2 edition of Methods of fatigue life improvement for welded joints in medium and high strength steels found in the catalog.

Methods of fatigue life improvement for welded joints in medium and high strength steels

S. Manteghi

Methods of fatigue life improvement for welded joints in medium and high strength steels

by S. Manteghi

  • 142 Want to read
  • 37 Currently reading

Published by TWI in Cambridge .
Written in English


Edition Notes

Includes bibliographical references.

Statementby S. Manteghi.
Series637/1998
ContributionsWorld Centre for Materials Joining Technology.
The Physical Object
PaginationVarious pagings :
ID Numbers
Open LibraryOL18965637M

Welding is a manufacturing method used to join various materials in order to form an assembly. During welding, joints are formed between two or more separate pieces of material. A welded joint subjected to cyclic loading could fail due to fatigue. Fatigue results from this cyclic loading, as well as strains, in the material. Throughout a welded assembly's life, cracks, which reduce the fatigue. The article presents the results of research on low cycle fatigue strength of welded joints of structural steel SQL. Two types of butt welds were analysed: I-joints and V-joints. The tests were performed under load controlled using the total strain amplitude εac. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue.

fatigue strength in other environments - E.g. ASME Boiler& Pressure Vessel Code fatigue design curves founcl to be non-conservativefor steels in high temperature water-Sea waterreduces fatigue strength ofwelded tubular connections in offshore oil rigs • Termed "corrosion fatigue" • Fatigue data for the specific environment should be used. L. High-frequency mechanical impact is a recent improvement method which is probably one of the most effective for treating welded assemblies. A number of experimental results relating to this process are presented in this article. These results lead to better understand the mechanisms of the process, to outline the influence of the operating parameters and to confirm the role played by the.

All the test specimens are welded with robotized GMAW except of two butt joints that are welded by fiber laser. In addition, the effect of post-weld treatments on the fatigue strength is investigated. Some of the joints are post-weld treated by high frequency impact treatment (HiFIT) or . curve for improved weld is quite high. Two of the specimens treated by ultrasonic impact treatment failed outside the weld, the cracks initiated at small defects on the plate. The improvement in fatigue strength at two million cycles is more than 90 %, corresponding to a factor on life of 20 over the entire range of the data. As welded.


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Methods of fatigue life improvement for welded joints in medium and high strength steels by S. Manteghi Download PDF EPUB FB2

Methods of fatigue life improvement for welded joints in medium and high strength steels (Industri [pdf / MB] Member Report / TWI Industrial Member Report Summary / S Manteghi.

The fatigue strength of mild and high strength steel plates and their welded joints is studied with respect to stress concentration factor (Kt) and welding residual stress.

Fatigue strength improvement of welded joints using SBHS by applying ICR treatment. With Y. Ono, K. Kinoshita In the background of requirements to weight reduction and cost saving, the application of high strength steels in steel bridges has been : Y.

Ono, K. Kinoshita. From a fatigue strength consideration a welded joint represents a weak link in a structure. While the fatigue limit in terms of stress range for a polished specimen is approximately equal to the ultimate tensile strength (UTS) of the material, the fatigue strength of unnotched plates with as-rolled surface is of the order of one-third of this (Gurney, ).Cited by: 3.

Watkinson F, Bodger PH and Harrison JD: The fatigue strength of welded joints in high strength steels and methods for its improvement. Proceeding Conference Fatigue of Welded Structure, The Welding Institute, Google ScholarCited by: 4. Fatigue life is a key concern in welded-steel frames for mobile equipment that experience large and varying dynamic loads.

For engineers who design welded-steel structures subject to dynamic. Furthermore, the knowledge of the cumulative fatigue behavior is required for reliable fatigue life assessment.

Therefore, in this paper the cumulative damage of four fine-grained steels with different strength grades (medium to high) SN, SM, SQ and SQ in welded.

This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel.

The processes investigated are: burr grinding, TIG dressing and ultrasonic impact treatment. In a review of published experimental data on the fatigue strength of welded joints improved by HFMI peening methods, Yildirim and Marquis identified 19 publications containing fatigue data for welded steel joints improved by one of the HFMI methods mentioned in the introduction.

Some of these studies contained multiple materials, improvement. To improve the fatigue properties in the welded joints of high strength steels, we developed an elongated bead method for low transformation temperature (LTT) welding materials. The proposed method intensifies the compressive residual stress and reduces the stress concentration.

We investigated the length of the elongated bead in the boxing fillet portion of the gusset front, the. Fatigue life curves of butt joints, transverse stiffeners and sample components with tube-clevis connections, manufactured by active gas metal arc welding (GMAW) of SQL, SM and SQL high-strength steels, show a linear extension into the low cycle fatigue (LCF) regime with a constant slope up to the yield strength of the material.

In the past decade, high-frequency mechanical impact (HFMI) has significantly developed as a reliable, effective, and user-friendly method for post-weld fatigue strength improvement technique for welded structures.

During this time, period 46 documents on HFMI technology or fatigue improvements have been presented within Commission XIII of the International Institute of Welding. By rearranging existing fatigue test results, fatigue performance of typical welded joints, (longitudinal, cruciform and out‐of‐plane gusset welded joint) are discussed with respect to the dependence on steel strength and on joint size.

The relationship between fatigue strength and steel strength was not clear for longitudinal welded joints. Fatigue resistance of welded joints of SQL high strength steels. Ádám Dobosy*, Dr. János Lukács ** *, ** Institute of Materials Science and Technology, University of Miskolc, Miskolc, Hungary * [email protected], **@ Abstract—In our days the high strength steels are used increasingly greater fields, especially in welded structures.

Abstract. paper provides an overview of published experimental data on the fatigue strength of welded joints by high frequency mechanical impact (HFMI) treatment methods, In total, data points from four specimen types are available,tests were performed using constant amplitude R = axial tension fatigue, but some data for other R rations, variable amplitude testing and bending fatigue.

The latter improvement methods, however, need to be performed separately and, in the literature, they are generally known as fatigue strength improvement by post-weld treatment methods. Post-weld treatment methods can be classified into two groups, (i) weld profile modification methods and (ii) weld residual stress modification methods.

1) The method yields the highest fatigue strength improvement compared to other post-weld improvement techniques such as grinding, TIG-dressing or shot peening, especially in the high.

“Fatigue strength improvement of steel structures by high- frequency mechanical impact: proposed procedures and quality assurance guidelines,” Welding in the World, vol. High frequency mechanical impact (HFMI) treatment is a reliable and utmost effective method for post-weld fatigue strength improvement of steel joints, especially in case of high-strength steel.

Other methods include peening, or remelting the toe by TIG or plasma dressing. All these techniques require definition of a detailed method statement and appropriate training for the operator.

If fatigue failure occurs in the throat of a fillet weld, simply increasing the weld size or changing to a full penetration weld will give an improvement. High-frequency mechanical impact (HFMI) has emerged as a reliable, effective and user-friendly method for post-weld fatigue strength improvement technique for welded structures.characteristic of as-welded joints is that the fatigue strength is almost independent of the material strength, which results in the impossibility of using higher strength steel to meet the requirements of high dynamic load projects.

At present, all the fatigue design criteria of welded joints are established based on this point.The fatigue strength of welded joints can be substantially improved by a number of methods.

This paper will investigate the high cycle fatigue strength that is attainable in joints of high strength steels in the as-welded and hammer peened condition. A T-joint with a longitudinal fillet weld.