Analysis of Quality of Welded Joints of Iron-Concrete Products

2019 ◽  
Vol 942 ◽  
pp. 121-130 ◽  
Author(s):  
Ludmila Redko ◽  
Inna Plotnikova ◽  
Nataliya Chicherina ◽  
Olga Tchaikovskaja ◽  
Josefa Bastida
Keyword(s):  
Economic Development ◽  
Life Cycle ◽  
Statistical Methods ◽  
Welded Joints ◽  
Failure Modes ◽  
Welding Process ◽  
Negative Effects ◽  
High Quality ◽  
Welded Structures

The search for effective methods of management is one of the strategic directions of economic development. To obtain high-quality products, organizations should manage nonconformities and causes of product defects. The paper focuses on the analysis of groups of defects of welded joints using statistical methods. Welding process was considered as one of the processes of management. The possible causes of nonconformities were indicated. The method of failure modes and effects analysis was used to quantify the level of risk. A matrix of consequences and probabilities was presented, and critical risks and risk situations were selected. The proposed measures to eliminate or minimize negative effects enable identification of problem areas of the life cycle of welded structures.

Features of the Heating Process in Ultrasonic Welding of Polycarbonate Products under Independent Pressure

2020 ◽  
pp. 54-62
Author(s):  
S.S. Volkov ◽  
A.L. Remizov ◽  
A.S. Pankratov
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Heating Process ◽  
Mechanism Of Formation ◽  
High Quality ◽  
Acoustic Contact ◽  
Welding Pressure

This paper presents a mechanism of formation of a hard-to-weld polycarbonate joint by ultrasonic welding. The method utilizes internal and external friction occurring in the welded joint area on abutting surfaces due to shear vibrations of the end of the upper part relative to the lower part. A layer of the heated welded material is formed, localized by thickness, in which predominant absorption of the ultrasonic vibrations occurs, which allows one to obtain high-quality and durable welded joints without significant deformation due to the concentration of thermal energy in the welding zone. The effect of independent welding pressure on the strength of the welded joint of polycarbonate is considered. A new method of ultrasonic welding under the conditions of independent pressure is proposed. The method consists of dividing the static welding pressure into two components: the pressure of the acoustic contact in the zone of contact of the waveguide with the product, and the welding pressure that compresses the welded products, with the latter component being lower than the former. In order to obtain high-quality welded joints made of polycarbonate and to prevent displacement of the welded edges during the welding process relative to each other, a special preparation of the welded edges is developed, which allows one part to be moved vertically relative to the other during the welding process. It is established that the quality of welding depends on the speed of movement and the angle of cutting the edges.

Evaluation of Influence of Thermal Methods of Metal Separation Cutting on Welding Quality

2017 ◽  
Vol 265 ◽  
pp. 755-761 ◽  
Author(s):  
A.K. Tingaev ◽  
M.A. Ivanov ◽  
A.M. Ulanov
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Heat Input ◽  
Experimental Studies ◽  
Welding Process ◽  
Regulatory Requirements ◽  
High Quality ◽  
Thermal Methods ◽  
Welding Seam

We have investigated a possibility of obtaining high-quality welded joints after oxygen and plasma cutting of steel С355 without removing the heat-affected zone (HAZ), in which the changes in chemical, phase and structural compositions are observed. Numerical and experimental studies of the effect of heat input of MAG and Submerged Arc welding on the quality of welded joints are performed. In particular, it was found that when the heat input of welding is at least 6.5 kJ/cm, the metal of HAZ of the edges after cutting is heated during the welding to temperatures above Ас3, which leads to its full recrystallization. When the heat input of welding is at least 10 kJ/cm, the edges after cutting are completely melted and become a part of the welding seam metal. The presence of extensive areas of melting and recrystallization of the edges in the welding process contributes to obtaining high-quality welded joints without removing the HAZ of the edges after cutting. To verify the results of numerical studies, experimental tests of control welded joints were conducted, which showed that the values of bending angle and impact toughness of the welding seam metal and heat affected zone are significantly above the regulatory requirements to quality of welded joints, and not less than the same requirements for steel С355. The obtained results confirm the possibility of revising domestic regulatory requirements for the steel constructions production in terms of the preparation of edges for welding using technologies of thermal cutting without subsequent machining.

SCIENTIFIC BASIS OF POSTGRADUATE TRAINING FOR OFFICER WORKING ETHNIC AFFAIRS USING STATE BUDGET IN THE PERIOD OF 2018 – 2025

2017 ◽  
Author(s):  
La Duc Minh ◽  
Nguyen Thi Hao ◽  
Vu Thi Thuy
Keyword(s):  
Economic Development ◽  
Ethnic Groups ◽  
Human Resource ◽  
Postgraduate Training ◽  
Scientific Basis ◽  
National Defense ◽  
High Quality ◽  
State Budget ◽  
International Integration

Ethnic affairs play an important role in socio of ethnic groups’ solidarity, assurance of security and national defense stability. In -economic development, maintenanceorder to improve the quality of ethnic affairs, it is practical to carry out postgraduate training of officer implementing ethnic affairs using state budget with the aim of encouraging and enhancing officer quality to satisfy high-quality human resource in international integration.

scholarly journals A study of the impact of information disclosure quality on the efficiency of corporate investment—Based on civil engineering listed companies

2020 ◽  
Vol 198 ◽  
pp. 03032
Author(s):  
Liying Zhang
Keyword(s):  
Life Cycle ◽  
Civil Engineering ◽  
Listed Companies ◽  
Investment Efficiency ◽  
Disclosure Quality ◽  
High Quality ◽  
Life Cycle Stages ◽  
Quality Disclosure ◽  
The Impact

Most of the existing studies on the impact of disclosure quality of listed companies on the investment efficiency of enterprises are based on the static level, and the article investigates the evolution of disclosure quality on the investment efficiency of enterprises from the dynamic level by dividing the life cycle of enterprises. Taking the data of Shenzhen civil engineering companies from 2013-2017 as the research sample, it uses multiple regression analysis to empirically test the impact of disclosure quality of listed companies on the investment efficiency of enterprises at different life cycle stages. The results show that when no distinction is made between life cycle stages, high quality disclosure can significantly inhibit the inefficient investment behavior of firms; in the growth and maturity samples, high quality disclosure can significantly inhibit underinvestment and overinvestment; in the recessionary samples, high quality disclosure can significantly inhibit underinvestment and has no significant effect on overinvestment.

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

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.

scholarly journals Laser Welding Of Finned Tubes Made Of Austenitic Steels

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.

scholarly journals Updated meta-review of evidence on support for carers

2018 ◽  
Vol 23 (3) ◽  
pp. 196-207 ◽  
Author(s):  
Jane Dalton ◽  
Sian Thomas ◽  
Melissa Harden ◽  
Alison Eastwood ◽  
Gillian Parker
Keyword(s):  
Mental Health ◽  
Systematic Reviews ◽  
Mental Health Problems ◽  
Psychosocial Support ◽  
Psychosocial Interventions ◽  
Negative Effects ◽  
High Quality ◽  
People With Dementia ◽  
Meta Review

Objective To update a 2010 meta-review of systematic reviews of effective interventions to support carers of ill, disabled, or older adults. In this article, we report the most promising interventions based on the best available evidence. Methods Rapid meta-review of systematic reviews published from January 2009 to 2016. Results Sixty-one systematic reviews were included (27 high quality, 25 medium quality, and nine low quality). The quality of reviews has improved since the original review, but primary studies remain limited in quality and quantity. Fourteen high quality reviews focused on carers of people with dementia, four on carers of those with cancer, four on carers of people with stroke, three on carers of those at the end of life with various conditions, and two on carers of people with mental health problems. Multicomponent interventions featured prominently, emphasizing psychosocial or psychoeducational content, education and training. Improved outcomes for carers were reported for mental health, burden and stress, and wellbeing or quality of life. Negative effects were reported in reviews of respite care. As with earlier work, we found little robust evidence on the cost-effectiveness of reviewed interventions. Conclusions There is no ‘one size fits all’ intervention to support carers. There is potential for effective support in specific groups of carers, such as shared learning, cognitive reframing, meditation, and computer-delivered psychosocial support for carers of people with dementia. For carers of people with cancer, effective support may include psychosocial interventions, art therapy, and counselling. Carers of people with stroke may also benefit from counselling. More good quality, theory-based, primary research is needed.

Using of Welding Virtual Numerical Simulation as the Technical Support for Industry

2016 ◽  
Vol 1138 ◽  
pp. 49-55
Author(s):  
Marek Slováček ◽  
Josef Tejc ◽  
Mojmír Vaněk
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Welded Joints ◽  
Welding Process ◽  
Austenitic Steels ◽  
Welding Parameters ◽  
Efficient Production ◽  
Weld Joints ◽  
Mechanical Properties Prediction

Welding as a modern, highly efficient production technology found its position in almost all industries. At the same time the demands on the quality of the welded joints have been constantly growing in all production areas. Great demand on the quality of the welded joints consequently causes more experimental or prototype – so called – validation joints that take place before the welding of final construction. These experiments, prototypes aim at – for instance – defining the appropriate welding technology, material, pre-heating, welding parameters, clamping condition and optimizing the welding process. Naturally, these experiments and prototypes make production more expensive. Numerical simulations of welding – in the area of production preparation as well as of production proper – have been frequently used recently. Numerical simulations supported by experimental measurements can simulate the actual welding process very close to reality. The new material models for hardness and mechanical properties prediction based on numerical simulation solution will be introduced.The paper covers some typical welding cases from energy industrial sector. The homogenous and heterogeneous weld joints from modern energy Cr-Mo-Ni-V steels (including modern austenitic steels) were done as prototype welding. The numerical simulation of these weld joints including post weld heat treatment process were done and welding technologies were optimised based on the numerical simulation results. The calculated hardness was compared with real measurements. During project the complete material properties which are needed for numerical simulation were measured. Simplify numerical lifetime prediction of weld joints including results from numerical welding analyse (as residual stresses and plastic deformation) were done.

scholarly journals Socio-economic Development and its Impact on Health Personnel in Regions of Visegrad Group Plus Countries

2019 ◽  
Vol 19 (1) ◽  
pp. 3-24
Author(s):  
Ingrid Majerová
Keyword(s):  
Economic Development ◽  
Health Personnel ◽  
Positive Impact ◽  
Generalized Method Of Moments ◽  
Environmental Issues ◽  
Socioeconomic Indicators ◽  
Negative Effects ◽  
The Impact ◽  
Visegrad Group

Abstract The quality of life and economic development of economies and their regions is influenced by socio-economic indicators such as unemployment, healthcare and education, environmental issues or household equipment. The question remains whether these indicators within regions can also influence each other and whether they have positive or negative effects. The paper aims to describe the impact of the selected socioeconomic indicators on health personnel, which was also divided from the gender perspective. For this purpose, the regions of the Visegrad Group Plus countries at NUTS II level were selected. The research was performed in the period from 2004 to 2013. According to our results based on the Generalized Method of Moments with panel data, we found out that a change in household income and a change in the number of vehicles in the monitored regions have the greatest (positive) impact on staff in hospitals. The research may contribute to the discussion about levels of regional economic development and the related competitiveness in terms of the socio-economic approach, and it may also provide a basis for further discussion on its measurement and use of appropriate indicators.

scholarly journals Environmental Regulations, the Industrial Structure, and High-Quality Regional Economic Development: Evidence from China

Land ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 517 ◽  
Author(s):  
Lingming Chen ◽  
Wenzhong Ye ◽  
Congjia Huo ◽  
Kieran James
Keyword(s):  
Economic Development ◽  
Industrial Structure ◽  
Environmental Regulations ◽  
Regional Economic Development ◽  
National Average ◽  
Mediating Effect ◽  
High Quality ◽  
Regional Economic ◽  
Regulatory Policies

Environmental regulation is an important means of restraining enterprises and protecting the environment. Rationalization of environmental regulatory policies can promote high-quality regional economic development. The optimization and upgrading of the industrial structure has an intermediary effect on the impact of environmental regulations on the high-quality development of the regional economy. After collating and analyzing previous research, this article proposes to classify 30 Chinese provinces into regions with higher than the national average HDI (human development index) and lower than the national average HDI based on the average HDI of Chinese provinces. We explore the mediating effect of industrial structure on environmental regulation and high-quality regional economic development. The model passed the full-sample robustness test and the robustness test with GDP as the replacement variable. The empirical results show that environmental regulations of different intensities have different effects on the quality of regional economic development. The effect of environmental regulations on development quality is mainly mediated through the transformation and upgrading of the industrial structure. Enterprises need reasonable incentives from environmental regulations to transform and upgrade. The mediating effect of the industrial structure on environmental regulations is greater in regions with below-average HDI values than in regions with above-average HDI values, which shows that the industrial structure is the mechanism underlying the effect of environmental regulations on the quality of regional economic development. This result proves that adjusting environmental regulatory policies can effectively promote the upgrading of industrial structure, thereby promoting high-quality regional economic development. Based on this, the article puts forward several policy recommendations.

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