Corrosion-mechanical resistance of 2219 alloy welded joints under simulated service conditions

L.I. Nyrkova;  ; T.M. Labur; E.I. Shevtsov; O.P. Nazarenko; A.V. Dorofeev;  ;  ;  ;

doi:10.37434/tpwj2021.10.03

Corrosion and mechanical resistance of welded joints of aluminium B1341T alloy, produced by argon arc welding using free and constricted arc

The Paton Welding Journal ◽

10.37434/tpwj2020.12.06 ◽

2020 ◽

Vol 2020 (12) ◽

pp. 40-47

Author(s):

L.I. Nyrkova ◽

◽

T.M. Labur ◽

S.O. Osadchuk ◽

M.R. Yavorska ◽

...

Keyword(s):

Welded Joints ◽

Arc Welding ◽

Mechanical Resistance

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The Influence of Heating Time on the Mechanical Properties of Laser Though-Transmission Welded Polyamide PPA40GF Joint

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.320.139 ◽

2021 ◽

Vol 320 ◽

pp. 139-143

Author(s):

Simonas Mindaugas Jankus ◽

Regita Bendikiene

Keyword(s):

Mechanical Properties ◽

Cross Section ◽

Welded Joints ◽

Laser Power ◽

Weld Seam ◽

Optical Microscope ◽

Heating Time ◽

Thermoplastic Composite ◽

Time Range ◽

Mechanical Resistance

The goal of this work was to investigate effect of heating time during welding on mechanical properties of High Performance Polyamide thermoplastic composite material PPAGF40. Studies showed that welded joints with shorter heating time from 6.1 s to 6.7 s had a higher amount of pores and burn mark defects compared to the welded joints with longer heating time. Cross-section analysis of welded samples revealed tendency, that samples with higher heating time from 7.4 s to 11.5 s possessed more homogenous weld seam and higher resistance to burst pressure, respectively from 5.1 bar to 7.5 bar, while the resistance to pressure values of shortest heating time range, respectively are varying from 3.3 bar to 3.9 bar. The weld seam defects like pores and burn marks weakened the welded joint. 470 W of laser power energy input influenced fast melt-down of a cover and a housing, which caused material partial evaporation and later on formation of pores inside weld seam. By using lower 450 W of laser power and scanning speed of 1900 – 1700 mm/s, we can observe more homogenous weld seam. The cross-section of the samples were examined by using optical microscope. Mechanical resistance to pressure was performed in order to evaluate the performance of welded joints of different heating time of PPAGF40.

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Aging Mechanism of Welded Joints of P92 Steels

Volume 3: Design, Materials and Manufacturing, Parts A, B, and C ◽

10.1115/imece2012-87497 ◽

2012 ◽

Author(s):

Changzheng Huang ◽

Cliff Yi Guo ◽

Jun Liang ◽

Jinfeng Du

Keyword(s):

Welded Joints ◽

Power Plants ◽

Weak Link ◽

Microscopic Analysis ◽

Aging Effect ◽

P92 Steel ◽

Aging Mechanism ◽

Service Conditions ◽

Carbide Particles

This paper concerns the study of aging mechanism of welded joints of P92 steels. Alloys like P92 steel are commonly used in ultra-supercritical (USC) power plants. Depending on the service conditions, the welded joints may become a critical weak link between component connections, showing crack openings and even failures. In this study, the long-term aging effect on the welded joints of P92 steels was investigated under the expected service temperature of 650°C. Microscopic analysis showed that under normal heat treatment, a weld joint has martensitic micro-structure with carbide particles of size 0.1∼0.2μm distributed along grain boundaries. After aging 1000h, white deposits are seen to precipitate from the grain and lath boundaries. Further aging makes these deposits to grow bigger and denser. After 7000h, the Laves phase may grow up to 1μm, causing the material to weaken and fail.

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The limits of human performance

Essays in Biochemistry ◽

10.1042/bse0440011 ◽

2008 ◽

Vol 44 ◽

pp. 11-26 ◽

Cited By ~ 14

Author(s):

Ralph Beneke ◽

Dieter Böning

Keyword(s):

Human Performance ◽

Safety Margin ◽

Afferent Input ◽

Metabolic Energy ◽

Human Organism ◽

Mechanical Resistance ◽

As Doping ◽

Gene And Protein Expression ◽

Underlying Mechanisms ◽

Biochemical Research

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

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