Some Problems of the Design and Quality of Automatically Welded Joints on Ship Hull Structure

It is well known that ship structure experiences residual stresses due to heat process of steelmaking and assembly (cutting, bending, welding, straightening, etc.), and that these stresses affect ship hull strength. However, such stresses are usually not considered in strength calculations, because they are quantitatively ambiguous. This paper reviews the residual stresses in ship hull structure in accordance with each production step, including steel material, with reference to past measurements and analyses.

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INVESTIGATION OF TRANSVERSE CRACKS IN ANNULAR WELDED JOINTS OF MAIN GAS PIPELINES LINEAR PART

Kontrol Diagnostika ◽

10.14489/td.2021.09.pp.034-041 ◽

2021 ◽

pp. 34-41

Author(s):

V. A. Zaznobin ◽

A. V. Nekrasov ◽

A. V. Pankratov

Keyword(s):

Welded Joints ◽

Linear Part ◽

Correct Identification ◽

Gas Pipelines ◽

Destructive Testing ◽

Transverse Cracks ◽

Additional Control ◽

Non Destructive

Statistics of accidents and incidents on main gas pipelines in recent years indicate that almost half of the technogenic events occur due to depressurization in the area of annular welded joints, mainly joints containing defects made during construction and installation work during the construction of gas pipelines. The assessment of the degree of danger and the timing of external inspection and repair or replacement of defective annular welded joints largely depends on the quality of non-destructive testing, the correct identification of the types of defects and the objective determination of their geometric dimensions. To increase the reliability of the assessment of the degree of danger of the detected defects, it is necessary to use additional control methods, in particular, destructive ones. The paper presents the results of surveys and tests of metal fragments of annular welded joints of main gas pipelines containing transverse cracks of annular welded joints in order to determine the causes of the formation of these defects and to assess the degree of danger of the detected transverse cracks of the installation welds of main gas pipelines.

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Features of ultrasonic control of butt welded joints of polyethylene pipes

10.36652/0042-4633-2020-11-46-52 ◽

2020 ◽

pp. 46-52

Author(s):

N.P. Aleshin ◽

D.M. Kozlov ◽

L.YU. Mogilner

Keyword(s):

Quality Control ◽

Welded Joints ◽

Ultrasonic Testing ◽

Ultrasonic Inspection ◽

Mechanical Tests ◽

Ultrasonic Control ◽

Lack Of Fusion ◽

Polyethylene Pipes ◽

End To End

The reliability of ultrasonic testing (UT) of the quality of welded joints of polyethylene pipelines, made end-to-end with a heated tool, is considered in comparison with mechanical tests and radiography. The greatest detection of solid defects is provided by ultrasonic inspection with the use of chord tipe probes (not less than 90 %). When detecting defects translucent for ultrasound (lack of penetration, lack of fusion, etc.), the reliability decreases to 70÷80 %. Keywords: welding, polyethylene pipeline, quality control, ultrasonic testing, chord tipe probe. [email protected]

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Assessment of the quality of spot-welded joints by ultrasonic testing

Welding International ◽

10.1533/wint.2006.3593 ◽

2006 ◽

Vol 20 (5) ◽

pp. 350-354

Author(s):

A Ambroziak ◽

Z Koralewicz ◽

M Korzeniowski ◽

P Kustron

Keyword(s):

Welded Joints ◽

Ultrasonic Testing ◽

Spot Welded

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DEVELOPMENT OF STRUCTURAL SOLUTIONS FOR PREVENTION OF WAVE RUN-UP OF THE BOW

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES MARINE ENGINEERING AND TECHNOLOGIES ◽

10.24143/2073-1574-2017-2-7-14 ◽

2017 ◽

pp. 7-14

Author(s):

Pavel Evgenievich Burakovskiy

Keyword(s):

Hydrodynamic Force ◽

Stability Loss ◽

Critical Value ◽

Ship Hull ◽

Hydrodynamic Impact ◽

Hull Structure ◽

Run Up ◽

Hull Damage ◽

Structural Solutions ◽

Navigation Safety

One of the most dangerous situations for seagoing ships is wave run-up in a head sea. In such a case, significant hydrodynamic forces appear resulting in stability loss or ship hull damage. The paper presents structural solutions that contribute towards navigation safety by means of decreasing probability of wave run-up of the ship bow in a head sea. A design has been developed of a ship stabilizer in the form of hinge-mounted stabilizing wings which deflect from the hull when the bow submerges in water and then cling to it when it emerges. The paper presents a new design of the bulwark with rotating sections able to rotate in the direction from the deck to the board. These designs can reduce dipping in a wave and reduce hydrodynamic impact on the bow. Apart from this, a hull structure has been proposed with a detachable bow to prevent capsizing of a ship. If the hydrodynamic force reaches a critical value, destruction of a permanent joint will happen in the proposed design, resulting in the situation when leak-proof aft and bow parts detach and remain afloat, which will allow the crew to evacuate. The proposed designs will increase navigation safety in storm conditions.

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Contributions Regarding the Use of Mechanical Vibrations in Order to Improve the Properties of Steels and Welded Joints Used in Metal Constructions

RECENT - REzultatele CErcetărilor Noastre Tehnice ◽

10.31926/recent.2020.61.067 ◽

2020 ◽

Vol 21 (2) ◽

pp. 67-71

Author(s):

Gheorghe Novac ◽

Bogdan Novac

Keyword(s):

Welded Joints ◽

Arc Welding ◽

Significant Contribution ◽

Welding Process ◽

Internal Stresses ◽

Welding Equipment ◽

Welding Technology ◽

Submerged Arc ◽

Very High

The paper presents aspects regarding the influence of vibrations on the mechanical properties of welded joints, made with basic materials of Spanish and Romanian origin. In this research is presented the practical way to make the necessary assemblies for the proposed tests. The tests show that vibrations have a significant contribution to the quality of welded joints. This is explained by the appearance of several crystallization centres which makes the structure finer. By using vibrations, the atoms are rearranged in the structure, ensuring a proper de-tensioning. The stresses induced in welded metals are significantly reduced by the use of vibration during welding process. The addition materials have a significant contribution to the emergence of stresses in welded joints as well. These stresses can contribute to the appearance of microstructural constituents with significant hardness. The welding equipment and technologies used also have a significant contribution to the emergence of the remaining stresses. For example, the submerged arc welding technology (SAF) can introduce very high internal stresses. By using vibrations during the welding process, it is achieved a fine structure and a significant reduction of remaining stresses in the welded joints.

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Possibilities of using scanning acoustic microscopy to analyze incompatibilities in braze welded joints

Welding Technology Review ◽

10.26628/wtr.v91i10.1074 ◽

2019 ◽

Vol 91 (10) ◽

pp. 7-15

Author(s):

Tomasz Piwowarczyk ◽

Marcin Korzeniowski ◽

Dawid Majewski

Keyword(s):

Aluminum Alloys ◽

Welded Joints ◽

Acoustic Microscopy ◽

Scanning Acoustic Microscopy ◽

Ultrasonic Techniques ◽

Titanium Grade ◽

Non Destructive

This article explores the possibilities of using non-destructive ultrasonic techniques to analyze the quality of lapped braze-welded joints. The tests were performed for 4 material groups (DC03+ZE steel and X5CrNi18-19 steel, aluminum alloys AW-5754 and AW-6061, titanium Grade 2 and copper Cu-ETP). As part of the work, additional materials and joint processes and its parameters were selected (TIG, MIG, laser). The quality of joints was monitored using scanning acoustic microscopy. Based on the A-scan andC-scan images, potential joints imperfections were determined. The possibilities of using advanced ultrasonic techniques to analyze the quality of braze joints was assessed.

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Laser Welding Of Finned Tubes Made Of Austenitic Steels

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0309 ◽

2015 ◽

Vol 60 (3) ◽

pp. 1807-1812

Author(s):

M. Stolecki ◽

H. Bijok ◽

Ł. Kowal ◽

J. Adamiec

Keyword(s):

Laser Welding ◽

Austenitic Steel ◽

Technological Process ◽

Welded Joints ◽

Austenitic Steels ◽

Tube Production ◽

High Quality ◽

Manufacturing Costs ◽

Finned Tubes

Abstract This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

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