Gliwice, Poland
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Restecka M.,Instytut Spawalnictwa | Wolniak R.,Silesian University of Technology
Archives of Metallurgy and Materials | Year: 2016

The most important issue for the producers nowadays is to meet the requirements of customers, satisfying their perceived but also the unperceived needs. In order to control the quality of welding processes correctly one must have knowledge of welding drawings, symbols, designs of welded joints, welding procedures, requirements set in codes and standards, also have knowledge of the techniques of inspection and testing connected with the automotive industry. The article shows ways to increase quality in the industry through the use of robotization and computerization. Presented examples and application of IT systems in aid of welding processes quality management in the automotive industry. © 2016 Polish Academy of Sciences.

Klobcar D.,University of Ljubljana | Kosec L.,University of Ljubljana | Pietras A.,Instytut Spawalnictwa | Smolej A.,University of Ljubljana
Materiali in Tehnologije | Year: 2012

A study was made of the weldability of 4-mm-thick aluminium-alloy 5083 plates using friction-stir welding. A plan of experiments was prepared based on the abilities of a universal milling machine, where the tool-rotation speed varied from 200 r/min to 1250 r/min, the welding speed from 71 mm/min to 450 mm/min and the tool tilt angle was held constant at 2°. The factors feed per revolution (FPR) and revolution per feed (RPF) were introduced to get a better insight into the friction-stirring process. Samples for microstructure analyses, Vickers micro-hardness measurements and special miniature tensile-testing samples were prepared. The microstructure was prepared for observation on a light microscope under a polarised light source. A set of optimal welding parameters was determined at a FPR of 0.35 mm/r, at which quality welds can be made with a minimal increase in the weld hardness and an up to 15 % drop in the tensile strength.

Agency: European Commission | Branch: FP7 | Program: BSG-SME | Phase: SME-1 | Award Amount: 1.20M | Year: 2011

The SignaStir project will develop an effective in-process quality assurance system for the inspection of friction stir welds (FSW) predominantly used in the manufacture of aluminium rolling stock and marine vessels. The SignaStir system will determine the unique and holistic weld quality signature. There is currently no capable inspection system available on the market either as a stand-alone unit or integrated with a welding machine to perform this task. Welding is an enabling manufacturing technology for joining materials, which directly affects cost, safety and reliability and therefore has significant economic impact. Production and supply of flawed or defective welds is unacceptable and may result in unsafe products of low structural integrity. To overcome the technical barriers to development of such an inspection system an SME partnership will require the services of research and technology providing organisations to deliver precompetitive research leading to the development of the product. There is a need for a low cost welding method, which can overcome the limitations of conventional fusion welding techniques. FSW has many economic, environmental and safety advantages over conventional welding but is a relatively new development and potential users require added confidence to make the initial capital investment required. The full benefit of the FSW process can only be achieved through application where weld quality is guaranteed to be correct each and every time. When developed the SignaStir system will give European manufacturers added confidence in their welded products and reduce costly off-line inspection of production parts. Scrap and re-work rates will be reduced as quality issues will be detected immediately after welding by the SignaStir system.

Pilarczyk W.,Silesian University of Technology | Pilarczyk A.,Instytut Spawalnictwa
Materiali in Tehnologije | Year: 2015

The primary objective of the article is to present an innovative workstation and the test results related to iron-based bulk metallic glasses made by pressure casting into a copper die that is cooled with Peltier modules. A production of bulk metallic glasses by pressure casting into a copper die, including an innovative cooling method is presented in this article. The equipment for the casting, including a modern high-frequency induction heater and a control-measuring apparatus, which enables the repeatability and maintenance of the process parameters, is discussed. Semiconductor Peltier modules for cooling the molds are presented. The tests show that the semiconductor Peltier modules are a suitable substitute for the water cooling of the molds. They enable the casting at 0 °C of the molds. Additionally, the ecological and economic aspects of the introduced new methods are presented. The application of the innovative cooling technology also has an influence on a simplification of the equipment construction for the casting process. The test results for the bulk metallic glasses based on iron and obtained with the designed devices are presented in this paper. A structure analysis using X-ray examination and microscopic observation was performed. The diffraction pattern and microscopic observation revealed that the studied as-cast Fe-Co-B-Si-Nb alloy is in the amorphous state. The test results confirmed the amorphous structure of the obtained materials.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP-2008-2.5-2;NMP-2008-2.5-1 | Award Amount: 4.82M | Year: 2009

Welding is the most economical and effective way to join metals permanently, and it is a vital component of our manufacturing economy. In welding, work-pieces are mixed with filler materials and molten, to form a pool of metal that upon solidification becomes a strong, permanent joint. Our ability to weld a metal to itself and to other materials is determined by the chemistry at the interface and by the complex morphology of the individual crystals at the weld centre. These boundaries are the critical regions where most catastrophic failures occur. Our project will establish the capability to design and engineer welding processes with a multi-scale, multi-physics computational modelling approach. An integrated suite of modeling software will be developed and validated, able to describe the key phenomena of the welding process at all relevant length scales, with a special emphasis on the solid-liquid interface evolution, including the description of macro-scale mass flow and thermal profiles, meso-scale solid/liquid interface movements, micro/nano-scale grain boundary and morphology evolution, mechanical integrity, and service life of the welded product. A unique aim of this project will be the prediction of interface evolution in industrially relevant systems, such as steel/steel and steel/Ni-based alloys. Validation will be ensured by state-of-the-art experimental techniques, including real-time synchrotron X-ray imaging, to observe morphological evolution of the interfaces, and electron microscopy and atom probe measurements to characterise chemistry in grain boundaries. This project will deliver an accurate, predictive, and cost-effective tool that will find widespread application in the relevant European industry for penetrating novel markets of high economic and strategic importance enabled by a new capability for intelligent design of high performance welded systems and interfaces, an essential task to ensure that Europe maintains its competitiveness.

The paper deals with an investigation of technological possibilities to produce T-joints of Al 6082 by friction stir welding technique and mechanical properties of the joints. It was indicated the importance of preparation proper welding stand by showing joints quality, presented on macrostructures, obtained with and without specially designed equipment for welding T-joints. Different ways of base metal preparation prior to welding (T-joints welded as two pieces and as three pieces), as well as two various shapes of steel dies directly forming the shape of tee connections, were used in experiments. It was shown how welding conditions influence structure and static properties of friction stir welding joints. Results show that for specified tool speeds significant imperfections, like voids, were formed. The best experimentally defined welding parameters, ensures lack of voids, were used to produce test joints for fatigue test. For the tested friction stir welding T-joints the fatigue category FAT were determined and compared to FAT categories of equivalent T-joints welded by conventional fusion welding. The study reveals also metallographic macroscopic and microscopic examination results, indicated typical imperfections arising during friction stir welding process of T-joints, as well as results of hardness measurement of joints cross section. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Weglowski M.S.,Instytut Spawalnictwa
Key Engineering Materials | Year: 2013

The effect of rotational and travelling speeds and down force on the torque in Friction Stir Processing (FSP) process are presented. To find a dependence combining the spindle torque acting on the tool with the rotational speed, travelling speed and the down force, the artificial neural networks have been applied. Studies have shown that the increase in the rotational speed causes decrease in the torque while the increase in the travelling speed and down force causes the increase in the torque at the same time. The relationship between parameters of the process and the temperature of the tool, based on measurement head TermSTIR, were presented. Tests were conducted on casting aluminium alloy AlSi9Mg. Application of FSP process resulted in a decrease in the porosity in the modified material and microstructure refining. Copyright © 2013 Trans Tech Publications Ltd.

The aim of the study was to investigate the effect of vibration welding parameters on the structure ofwelding region in polyamide 66 joints. The quality of jointswas examined under an optical microscope using polarized light. Differential scanning calorimetry (DSC) was used to study the influence of welding parameters: vibration amplitude (a),welding pressure (pz) andweld time (tz) on the melting temperature and the crystalline phase content in the weld as well as the base material of the joints. For low welding pressure and amplitude values, an amorphous phase was dominant in the welding region (Fig. 6a), while for higher values of these parameters an increase in the crystalline phase contentwas observed (Fig. 7). The mechanical strength of PA 66 joints was evaluated using a static tensile test (Table 3). Maximum tensile strength was in the range of 70 to 77 % of the value for the base material.

Pietras A.,Instytut Spawalnictwa | Rams B.,Instytut Spawalnictwa
Archives of Foundry Engineering | Year: 2016

The article contains basic information associated with the impact of the FSW process parameters on the forming of a weld while friction welding of aluminium casting alloys. Research was conducted using specially made samples containing a rod of casting alloy mounted in the wrought alloy in the selected area of FSW tool acting. Research has thrown light on the process of joining materials of significantly dissimilar physical properties, such as casting alloys and wrought alloys. Metallographic testing of a weld area has revealed the big impact of welding conditions, especially tool rotational speed, on the degree of metal stirring, grain refinement and shape factor of a weld. As the result of research it has been stated that at the high tool rotational speed, the metals stirring in a weld is significantly greater than in case of welding at low rotational speeds, however this fails to influence the strength of a weld. Plastic strain occurring while welding causes very high refinement of particles in the tested area and changing of their shape towards particles being more equiaxial. In the properly selected welding conditions it is possible to obtain joints of correct and repeatable structure, however in the case of the accumulation of cavities in the casting alloy the FSW process not always eliminates them. © 2016 A. Pietras et al., published by De Gruyter Open 2016.

Weglowska A.,Instytut Spawalnictwa | Pietras A.,Instytut Spawalnictwa
Archives of Civil and Mechanical Engineering | Year: 2012

Because of very attractive mechanical properties, nylons make interesting group of materials, used in many engineering applications. Vibration welding is a welding method used to join various kinds of thermoplastics. Almost 15% of all welds of thermoplastics are made with the use of vibration welding. The ability of vibration welding of different kind of polymers may present cost advantage over the other welding techniques and may allow to produce elements of lower weight and of a high quality. This work presents results of vibration welding of dissimilar materials joints made of nylon 66 (PA66) and 30% glass fibres nylon 66 (PA66 GF30). The aim of the studies was to determine the influence of the welding conditions on the quality of vibration welded joints. The quality assessment was done on the base of tensile tests and microscopy examination, conducted on light microscopy and scanning electron microscopy (SEM). Results of the tensile test indicate that it is possible to achieve good quality of joints at the proper welding conditions. The light microscopy examination showed that the welding parameters influence the orientation of the glass fibres in the weld zone, on the continuity of the material in the weld and on the thickness of the weld. The results of the SEM indicate that the vibration welded joint is formed as a result of joining of the matrixes of two welded nylons. © 2012 Published by Elsevier Ltd.

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