scholarly journals Autogenous Fiber Laser Welding of 316L Austenitic and 2304 Lean Duplex Stainless Steels

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2930 ◽  
Author(s):  
Michał Landowski ◽  
Aleksandra Świerczyńska ◽  
Grzegorz Rogalski ◽  
Dariusz Fydrych
Keyword(s):  
Fiber Laser ◽  
Stainless Steels ◽  
Welded Joints ◽  
Duplex Stainless Steels ◽  
Bending Test ◽  
Ferrite Content ◽  
Magnetic Method ◽  
Destructive Testing ◽  
Non Destructive

This study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non-destructive testing (visual and penetrant), destructive testing (static tensile test, bending test, and microhardness measurements) and structure observations (macro- and microscopic examinations, SEM, element distribution characteristics, and ferrite content measurements). Non-destructive tests and metallographic examinations showed that the welded joints meet the acceptance criteria for B level in accordance with EN ISO 13919–1 standard. Also the results of the destructive tests confirmed the high quality of the joints: specimens were fractured in base material with lower strength—316L austenitic stainless steel and a 180° bending angle was obtained confirming the high plasticity of the joints. Microscopic examination, SEM and EDS analysis showed the distribution of alloying elements in joints. The microhardness of the autogenous weld metal was higher by about 20 HV0.2 than that of the lean duplex steel. Ferrite content in the root was about 37% higher than in the face of the weld. The Schaeffler phase diagram was used to predict the phase composition of the welded joints and sufficient compliance with the magnetic method was found. The presented procedure can be used for welding of 316L–2304 stainless steels dissimilar welded joints of 8 mm thickness without ceramic backing.

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

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.

Grading of structural timber of Populus × euramericana clone I-214

Holzforschung ◽  
2012 ◽  
Vol 66 (5) ◽  
pp. 633-638 ◽  
Author(s):  
Milagros Casado ◽  
Luis Acuña ◽  
Luis-Alfonso Basterra ◽  
Gemma Ramón-Cueto ◽  
Daniel Vecilla
Keyword(s):  
High Strength ◽  
Bending Test ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Visual Grading ◽  
Populus Euramericana ◽  
Four Point Bending ◽  
Low Elastic Modulus ◽  
Non Destructive

Abstract Grading tests were performed on 338 poplar wood samples (Populus × euramericana I-214) with dimensions of 150×50 mm2, 150×80 mm2, and 200×100 mm2 prepared for structural utilization. The non-destructive testing methods included ultrasound (Sylvatest) and induced vibrations (Portable Lumber Grader) combined with visual grading criteria. Additionally, screw withdrawal resistance was tested by the instrument Fakopp. These results were compared with those obtained by a four-point bending test according to the EN 408 (2004) standard. Ultrasound and induced vibrations overestimated the quality of this type of wood. Correlation equations are proposed to determine the true characteristics for each testing method. It can be concluded that poplar timber from clone I-214 has acceptable flexural strength, but a comparatively low elastic modulus, whereby it is not graded within a high strength class according to the EN 338 (2009) standard.

scholarly journals Analysis of Using Acoustic Microscopy to Evaluate Defects in Spot Welding Joints

2016 ◽  
Vol 61 (2) ◽  
pp. 1009-1019 ◽  
Author(s):  
M. Korzeniowski ◽  
B. Białobrzeska
Keyword(s):  
Light Microscopy ◽  
Welded Joints ◽  
Spot Welding ◽  
Acoustic Microscopy ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Welding Joints ◽  
Microscopy Techniques ◽  
Non Destructive

AbstractThe article presents the possibilities of using acoustic microscopy to evaluate defects in resistance spot welding joints. For this purpose, the welded joints were made from two grades of aluminium plates EN AW5754 H24 and EN AW6005 T606, which were then subjected to non-destructive testing using acoustic microscopy and conventional destructive testing using traditional light microscopy techniques. Additionally, the study examined the influence of the typical contaminants found in industrial conditions on the quality of the joint.

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