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1

Hardfacing of mild steel with wear-resistant Ni-based powders containing tungsten carbide particles using powder plasma transferred arc welding technology

Appiah Augustine Nana Sekyi, Bialas Oktawian, Żuk Marcin, Czupryński Artur, Konadu Sasu David, Adamiak Marcin

Materials Science Poland

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2022

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Vol. 40, No. 3

42--63

EN

This study explores the use of powder plasma transferred arc welding (PPTAW) as a surface layer deposition technology to form hardfaced coatings to improve upon the wear resistance of mild steel. Hardfaced layers were prepared using the PPTAW process with two different wear-resistant powders: PG 6503 (NiSiB + 60% WC) and PE 8214 (NiCrSiB + 45% WC). By varying the PPTAW process parameters of plasma gas flow rate (PGFR) and plasma arc current, hardfaced layers were prepared. Microscopic examinations, penetration tests, hardness tests, and abrasive wear resistance tests were carried out on the prepared samples. Hardfacings prepared with PG 6503 had a hardness of 46.3–48.3 HRC, while those prepared with PE 8214 had a hardness of 52.7–58.3 HRC. The microhardness of the matrix material was in the range of 573.3–893.0 HV, while that of the carbides was in the range of 2128.7–2436.3 HV. The abrasive wear resistance of the mild steel was improved after deposition of hardfaced layers by up to 5.7 times that of abrasion-resistant heat-treated steel, Hardox 400, having a nominal hardness of approximately 400 HV. The hardness and wear resistance were increased upon addition of Cr as an alloying element. Increasing the PGFR increased the hardness and wear resistance of the hardfacings, as well as increasing the number of surface cracks. Increasing the plasma transferred arc (PTA) current resulted in hardfacings with fewer cracks but lowered the wear resistance.

2

Microstructure, toughness and hardness of a simulated HAZ in steel S1100QL and of the HAZ of an actual MAG-welded joint made using a metallic flux-cored wire

Łomozik Mirosław

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2021

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Vol. 65, No. 5

47--65

EN

Simulation tests discussed in the article involved structural steel S1100QL having a yield point of more than 900 MPa. The simulations included single (Tmax = 1250°C) and double welding thermal cycle (Tmax = 1250°C + 600°C, Tmax = 1250°C + 760°C and Tmax = 1250°C + 900°C) as well as cooling times t8/5 = 3, 5 and 10 s. Specimens with the simulated heat affected zone (HAZ) were subjected to impact strength tests performed at a temperature of -40°C and +20°C, Vickers hardness tests (HV10) and microscopic metallographic tests (involving light microscopy). Test results were presented in diagrams and photographs. Related comparisons included results of the structural, hardness and toughness tests of simulated HAZs with analogous results obtained during the actual repair welding of a MAG-welded joint made of steel S1100QL. The final part of the article contains discussion concerning the test results and the statement concerning the obtainment of the significant conformity of the phase composition and the morphology of the microstructure as well as the average hardness values of the HAZ areas obtained in the simulations and those of the HAZ area obtained in the actual welded joint. In relation to all tested simulation variants, the impact energy of the simulated HAZ area of steel S1100QL satisfied the minimum criterion of KV = 27 J both in relation to a test temperature of -40°C and that of +20°C. The number of repeated (1 through 4) thermal cycles having preset parameters did not trigger explicitly noticeable changes in impact energy values as regards the simulated HAZ of steel S1100QL.

PL

Przedmiotem badań symulacyjnych opisanych w artykule była stal konstrukcyjna o granicy plastyczności powyżej 900 MPa typu S1100QL. Zostały przeprowadzone symulacje dla pojedynczego (Tmax= 1250°C) i podwójnego cyklu cieplnego spawania (Tmax= 1250°C + 600°C, Tmax 1250°C + 760°C oraz Tmax= 1250°C + 900°C), dla czasów chłodzenia t8/5= 3, 5 i 10 s. Próbki z zasymulowanymi obszarami SWC poddano badaniom udarności w temperaturach -40°C oraz +20°C, pomiarom twardości sposobem Vickersa HV10 oraz badaniom metalograficznym mikroskopowym przy użyciu mikroskopii świetlnej. Wyniki badań zestawiono na wykresach i na zdjęciach fotograficznych. Porównano uzyskane wyniki badań: strukturalnych, twardości oraz udarności symulowanych obszarów SWC z analogicznymi wynikami badań rzeczywistego naprawczego złącza spawanego stali S1100QL, wykonanego metodą MAG. Na zakończenie omówiono wyniki badań i stwierdzono m.in. że uzyskano dużą zgodność składu fazowego i morfologii mikrostruktury oraz średnich wartości twardości obszarów SWC otrzymanych w wyniku symulacji i obszaru SWC w naprawczym złączu spawanym. Ponadto praca łamania symulowanego obszaru SWC stali S1100QL, dla wszystkich badanych wariantów symulacji, spełniała kryterium minimalnego KV = 27 J zarówno przy temperaturze badania -40°C, jak i +20°C. Krotność powtórzeń cyklu cieplnego o zadanych parametrach w zakresie od jednokrotnego do czterokrotnego nagrzewania nie powodowała jednoznacznej tendencji zmian wartości pracy łamania symulowanych obszarów SWC stali S1100QL.

3

Analysis of selected properties of induction welded seamed tubes

Techmański Zbigniew, Stępień Mariusz, Stępień Jacek

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2021

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Vol. 65, No. 5

31--36

EN

The article discusses research work concerning an innovative welding technology enabling the continuous joining of steel tubes using the high-frequency induction heating process. The article focuses primarily on issues related to weld formation, particularly as regards the formation of the heat affected zone (HAZ), enabling the obtainment of the proper angle of a material flow line (referred to as the upsetting line), appropriate proportions of the HAZ and the ferritic line. The proper performance of the technological process enables the obtainment of a high-quality joint (tube seam) superior to that obtained using previous solutions and satisfying safety-related requirements concerning pipelines used in the transport of liquids and gases characterised by low operating pressure. The results presented in the article were obtained in metallographic tests of the joints. The test results revealed the obtainment of joints characterised by required quality.

PL

Artykuł poświęcony jest pracom nad innowacyjną technologią zgrzewania rur stalowych w sposób ciągły w procesie nagrzewania indukcyjnego wysokiej częstotliwości. Artykuł, w główniej mierze, odnosi się do zagadnień związanych z procesem powstawania zgrzeiny, a w szczególności do sposobu kształtowania strefy wpływu ciepła SWC pozwalającego na uzyskanie właściwego kąta linii płynięcia materiału – tzw. linii spęczania – właściwych proporcji SWC i linii ferrytycznej. Przeprowadzenie procesu technologiczno-technicznego we właściwy sposób pozwala na uzyskanie wysokiej jakości połączenia (szwu rury) przewyższającego dotychczasowe rozwiązania i tym samym spełniającego wymogi bezpieczeństwa dla rurociągów transportowych cieczy i gazów o niskich ciśnieniach roboczych. Zamieszczone w artykule wyniki odnoszą się do badań metalograficznych wykonanych na połączeniach testowych. Badania te wykazały uzyskanie oczekiwanych właściwości połączeń.

4

Microstructural evaluation of the high-frequency induction welded joints of low carbon steel pipes

Bunsch Adam, Krawczyk Janusz, Matusiewicz Piotr

Advances in Materials Science

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2021

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Vol. 21, nr 4(70)

19--33

EN

The work presents the results of research on the structure of welded joints in the area of heat affected zone (HAZ). Based on precisely performed metallographic tests, the contribution of individual structural components in the area of welds of pipes welded with the induction method was assessed. The volume fraction of individual structural components in various areas of the heat affected zone, the size of the grain formed in the welding process, as well as its shape coefficients were determined. On the basis of metallographic observations, an attempt was made to describe the course of the pressure induction welding process, taking into account the structural changes, phase changes and the recovering and recrystallization processes taking place in this process.

5

Processing of printed circuit boards using a 532 nm green laser

Ciszewski Piotr, Sochacki Mariusz

Opto-Electronics Review

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2020

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Vol. 28, No. 4

197--202

EN

The paper describes a research on assessing the quality of edges resulting from the interaction of laser pulses with a material of rigid and flexible printed circuits. A modern Nd:YVO4 crystal diode-pumped solid-state laser generating a 532 nm wavelength radiation with a nanosecond pulse time was used for the research. Influence of laser parameters such as beam power and pulse repetition frequency on a heat affected zone and carbonization was investigated. Quality and morphology of laser-cut substrates were analyzed by optical microscopy. High quality laser cutting of printed circuit board substrates was obtained without delamination and surface damage, with a minimal carbonization and heat affected zone. The developed process was implemented on the printed circuit assembly line.

6

PC-GMAW effect on the welding thermal cycle and weld metal geometry for high strength steels

Zavdoveev Anatoliy, Poznyakov Valeriy, Kim Hyuong Seop, Rogante Massimo, Heaton Mark, Baudin Thierry

International Journal of Engineering and Safety Sciences

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2020

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Vol. 1

5–16

EN

Welding of medium carbon alloy steels used in the manufacture of special purpose machinery imposes to solve two mutually exclusive problems - to increase the depth of penetration of the base metal and to reduce the width of the thermal impact zone of the welded joints. To successfully solve this problem, it is necessary to use arc welding processes with a concentrated heat source. One of these processes is pulsed current gas metal arc welding (PC-GMAW). The present researches have allowed establishing, that with PC-GMAW change of welding current is a difficult character, namely: on high-frequency impulse signal (60 kHz), impulses of the current of low frequency (from 90–150 Hz) are imposed. The change in the values of the mean welding current at PC-GMAW is achieved by increasing the pause current and the frequency of high amplitude current pulses. It is shown that the PCGMAW allows reducing the amount of metal splashing, to increase the depth of penetration (almost 2 times) in comparison with stationary welding. At the same time, the cooling rate of HAZ metal in the temperature range 600-500°C decreases almost 1.5 times, which allowed to reduce the width of HAZ by 40%.

7

Analiza warunków technologicznych wytwarzania matryc kuziennych

Figna Anna, Figna-Zientz Ewa, Góral Jan, Górecki Artur, Rozpondek Maciej

Hutnik, Wiadomości Hutnicze

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2020

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Vol. 87, nr 11-12

264--267

PL

Przedstawiono parametry procesu technologicznego wytwarzania matryc kuziennych. Przeanalizowano wpływ czynników oddziaływujących bezpośrednio na trwałość matryc. Scharakteryzowano kryteria doboru materiałów na podłoże matrycy (rdzeń) i napoinę w aspekcie dostępności rynkowej w celu wykonania badań weryfikujących ich parametry technologiczne. W oparciu o teorię podobieństwa określono wartości strumieni cieplnych zapewniających stabilizację temperatury matrycy podczas procesu napawania.

EN

Parameters of the technological process of manufacturing forging closed - dies are presented. The influence of factors directly affecting the durability of the closed - dies was analyzed. The criteria for the selection of materials for the closed - dies substrate (core) and the padding weld were characterized in terms of market availability, in order to perform tests verifying their technological parameters. Based on the theory of similarity, the values of thermal fluxes ensuring the stabilization of the closed - dies temperature during the padding process were determined.

8

Influence of the welding joint type on safety properties of the armor steel ARMOX 500t

Lazić Vukić, Arsić Dušan, Nikolić Ružica, Uhričik Milan, Hadzima Branislav

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

753--759

EN

Steels of the ARMOX class belong into a group of the fine-grained, increased strength steels, which are manufactured by the quenching and low tempering procedure, with intensive thermo-mechanical treatment at high temperatures. Combination of the heat and mechanical treatments provides for the fine grains and exceptionally good properties of these steels, while the low-tempering enables relatively high hardness and good ballistic properties. This is why the welding of these steels can negatively affect the material properties in individual zones of the welded joint, what could lead to worsening of the material's ballistic properties, as well. The model plates were welded with the specially prescribed technology; the joints were the but-joint, corner joint and the joint with the shielding plate. In this paper are presented results obtained from the ballistic tests of the plates welded by the prescribed technology; tests consisted of shooting with three types of live ammunition at different types of the welded joints.

9

Heat affected zone analysis of Ti6Al4V after WEDM

Poroś Dariusz, Zaborski Stanisław, Karolczak Paweł

Mechanik

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2019

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R. 92, nr 12

833--835

EN

Perspectives of applications WEDM for cutting titanium alloys are presented. There is space to explore how application of proper time parameters and the material of wire electrode for WEDM of titanium alloys affects the surface roughness, structure, the stress and the chemical composition of the formed surface layer.

PL

Przedstawiono problematykę obróbki elektroerozyjnej tytanu z uwzględnieniem doboru parametrów czasowych oraz materiału elektrody drutowej. Podjęto także temat analizy geometrii obrobionej powierzchni i strefy wpływu ciepła.

10

Laser treatment with 625 Inconel powder of hot work tool steel using fibre laser YLS-4000

Dobrzański L. A., Jonda E., Pakieła W., Dziekońska M.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 91, nr 2

60--67

EN

Purpose: The purpose of this investigation was to determine the changes in the surface layer (Inconel 625), obtained during the laser treatment of tool-steel alloy for hot work by the use high-power fibre laser. Design/methodology/approach: Observations of the layer structure, HAZ, and substrate material were made using light and scanning microscopy. The composition of elements and a detailed analysis of the chemical composition in micro-areas was made using the EDS X-ray detector. The thickness of the resulting welds, heat affected zone (HAZ) and the contribution of the base material in the layers was determined. Findings: As a result of laser cladding, using Inconel 625 powder, in the weld overlay microstructure characteristic zones are formed: at the penetration boundary, in the middle of weld overlay and in its top layer. It was found that the height of weld overlay, depth of penetration, width of weld overlay and depth of the heat affected zone grows together with the increasing laser power. Practical implications: Laser cladding is one of the most modern repair processes for eliminating losses, voids, porosity, and cracks on the surface of various metals, including tool alloys for hot work. Laser techniques allow to make layers of materials on the repaired surface, that can significantly differ in chemical composition from the based material (substrate material) or are the same. Originality/value: A significant, dynamic development in materials engineering as well as welding technologies provides the possibility to reduce the cost of production and operation of machinery and equipment, among others by designing parts from materials with special properties (both mechanical and tribological) and the possibility of regeneration of each consumed element with one of the selected welding technologies.

11

About weldability and welding of Al alloys: case study and problem solving

Fracchia E., Gobber F., Rosso M.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 85, nr 2

67--74

EN

Purpose: Among many disciplines within engineering, welding is probably one of the most inexact – rather more of an art than a science. As weldment is meant the complete joint comprising the weld metal, heat affected zones (HAZ) and the adjacent parent metal and should have the same properties as the parent metal. This paper aims provides a basic understanding of the metallurgical principles involved in how aluminium alloys achieve their strength and how welding can affect these properties. The most important and applied welding processes to Al alloys are here shortly introduced, as well as the preparation of parent metals prior to welding and good welding practice to avoid and/or keep under control defects and failures. Some case studies with possible failures will be introduced together with actions and suggestions to solve the observed problems. Design/methodology/approach: Two sheets of the EN AW 5454 (AlMg3Mn) alloy were weld with resistance welding process and after a mechanical processing of lamination was observed the presence of the defect. The microstructure of the defect as well as the welded part were evaluated with stereomicroscope (LEICA MS5), optical microscope (LEICA MEF4M), and with SEM analysis (LEO 1540 VP equipped with an energy dispersive X-ray spectroscope Oxford Link Pentafet). Findings: The well welded part was analysed with optical microscopy and electronic microscopy resulting with the attended mechanical properties. Micro-hardness indentations on the joint demonstrated the good mechanical properties of the joint while with the microscopic observations were identified the orientation and presence of precipitates typical of this alloy. In the defect, microscopically observations showed the presence of oxide inclusions. Research limitations/implications: There are a number of problems associated with the welding of aluminium and its alloys that make it difficult to achieve this ideal. The features and defects that may contribute to the loss of properties comprise the following: gas porosity, oxide inclusions and oxide filming, solidification (hot) cracking or hot tearing, reduced strength in the weld and HAZ, lack of fusion, reduced corrosion resistance and reduced electrical resistance. Originality/value: This case study illustrated clearly the importance of the cleaning on the surfaces to obtain a well welded joint ensuring the desired mechanical properties.

12

The Influence of Different Assist Gases on Ductile Cast Iron Cutting by CO2 Laser

Meško J., Nigrovič R., Zrak A.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 4

109--114

EN

This article deals with the technology and principles of the laser cutting of ductile cast iron. The properties of the CO2 laser beam, input parameters of the laser cutting, assist gases, the interaction of cut material and the stability of cutting process are described. The commonly used material (nodular cast iron - share of about 25% of all castings on the market) and the method of the laser cutting of that material, including the technological parameters that influence the cutting edge, are characterized. Next, the application and use of this method in mechanical engineering practice is described, focusing on fixing and renovation of mechanical components such as removing the inflow gate from castings with the desired quality of the cut, without the further using of the chip machining technology. Experimental samples from the nodular cast iron were created by using different technological parameters of laser cutting. The heat affected zone (HAZ), its width, microstructure and roughness parameter Pt was monitored on the experimental samples (of thickness t = 13 mm). The technological parameters that were varied during the experiments included the type of assist gases (N2 and O2), to be more specific the ratio of gases, and the cutting speed, which ranged from 1.6 m/min to 0.32 m/min. Both parameters were changed until the desired properties were achieved.

13

A study on numerical analysis of the resistance spot welding process

Zhigang H., Kim I. S., Son J. S., Kim H.-H., Seo J. H., Jang K. C., Lee D. K., Kuk J.M.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 14, nr 1-2

140--145

EN

Purpose: Over the last few years, there has been a growing interest in quantitative representation of heat transfer and fluid flow phenomena in weld pools in order to study relationships between the processing variables and the quality of the weldment produced and to use this information for the optimization and mobilization of the welding process. Design/methodology/approach: A 2D axisymmetric Finite Element Method (FEM) model has been developed to analyze the transient thermal behaviors of Resistance Spot Welding (RSW) process. In this model, the temperature dependent material properties, phase change and convectional boundary conditions were taken account for the improvement of the calculated accuracy, but the determination of the contact resistance at the surface is moderately simplified in order to reduce the calculating time through the analysis. Findings: The developed model has been employed the thermal history of the whole process (including cooling) and temperature distributions for any position in the weldment. Research limitations/implications: Future research in the field of RSW processing could focus on analysis of the stress and strain distributions as well as deformation in the weldment. Originality/value: It can be concluded that the maximum temperature was up to 1346°C, nearly the molten point of mild steel, and verified by the observation of the surface of the weldment after welding

14

Analityczne oszacowanie zakresu strefy wpływu ciepła (SWC) podczas spawania

Śloderbach Z.

Dozór Techniczny

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2000

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z. 1

14--16