Welding Metallurgy Research Papers - Academia.edu (original) (raw)

Plasma metal deposition (PMD) is an additive manufacturing process capable of layer by layer construction , repair, and reconstruction of metallic parts. One of the important characteristics of cladding with PMD is the ability to control the wire feed, plasma arc energy, thus allowing the melt pool to be controlled. In this paper stainless steel 316L was deposited in the form of wire on a block of mild steel. Experiments were focused to infer the influence of plasma power, travel speed and wire feed rate on the quality of track. Different parameters were varied to observe the various geometrical parameters and their relationship with the energy source and material feed rate was established. The results show that plasma power and wire feed rate have a significant impact on height and width of the deposited track. Aspect ratios ranging from 0.85 to 4.6 were obtained. Higher values of aspect ratio at lower wire feed rates and at optimum plasma power was further used for deposition of defect free surface. An overlapping distance of 1.73 mm was used for surface cladding. This method can also be used for remanufac-turing of surface of moulds and die.

- by Francisco Ager
- •
- Etruscan, X-Ray Fluorescence (XRF) Spectroscopy, Soldering, Welding Metallurgy

В отходах пирометаллургического производства меди накоплено значительное количество отвальных шлаков. Даже при среднем содержании меди в них 0,30–0,80 %, видно, что потери металлы
составляет значительных. В этой связи задача создания рациональной и комплексной технологии переработки шлаков и промпродуктов медного производства является весьма актуальной. В статье рассмотрен инновационный метод снижения потерь меди со шлаком. Для проведения этого исследования
использованы восстановительно-сульфидирующих комплексы (ВСК), состоящие из клинкеров цинкового производства и хвостов обогатительных фабрик АГМК. Полученные результаты показывает, что внедрение данной технологии в промышленность позволит повысить комплексности использование сырья.

The scanning electron microscopy (SEM) and energy dispersive X-Ray analysis of the Al-Fe alloy revealed the formation of varying ironaluminide intermetallic compounds. The Al-Fe alloys were produced by varying the composition of Fe. The pure 'Al' billets were heated up to 750 о c and in the molten condition of aluminium 'Fe' powder was added resulting in an exothermic reaction. The exothermic reaction raised the molten bath temperature to ~ 1400 о c which activated the formation of intermetallic compound.

- by Ananthapadmanaban D
- •
- Manufacturing, Metal Casting, Welding Metallurgy

Har yili dunyo miqyosida insonlarning koʻpayishi, ishlab chiqarish va
sanoatning kengayishi katta shaharlarning globallashuvi bu - oziq-ovqat tanqisligi, ishlab chiqarish va sanoat chiqindi gazlari, qattiq hamda suyuq chiqindilari, maishiy chiqindilarni hosil boʻlishiga olib kelmoqda. Misol qilib aytsak, yer yuzida har kuni 11 250 000 tonnadan ortiq chiqindi hosil boʻladi va bu balandligi 3 km, eni 1 km boʻlgan chiqindi togʻi deganidir. Bundan tashqari, sanoat va ishlab chiqarish chiqindilari hajmi maishiy chiqindidan bir necha marotaba koʻproq miqdorni tashkil etadi. Bu holat esa kelajakda inson va atrof-muhitni qanday katta ekologik muammolarga duch kelishi mumkinligini isbotidir.

- by Sérgio Barra
- •
- Welding, Welding Metallurgy, Defeitos, Descontinuidades

The aim of this work is to investigate the influence of the welding process parameters on the weld bead geometry, microstructure characteristics, and mechanical properties of weldments curried out using TIG welding with pulsed/non pulsed current processes. The cooling state was introduces as an input parameter to investigate the main effects on the structure morphology and thereby the mechanical property. In this work the selected pulse frequency levels were 5-500 Hz in order to show the effect of low and high frequencies on the weldment characteristics of AISI 304L plates using filler metal of ER 308LSi. In this work, three levels four factors Taguchi L9 orthogonal array was used to analyze the aspect ratio of the welded specimens. Taguchi analysis was performed for the main effects plot to optimize the process parameters. Furthermore, the microstructure evolution has been investigated. Thus key findings of this work clarified that the pulse frequency has significant effect on the breaking of the dendrite arms during welding process and so strongly affects on the tensile strength. The cooling state also affects on the microstructure texture and thereby, the mechanical properties. The most important factor affects the bead geometry and aspect ratio is the travel speed.

There has been an increase in Advanced High-Strength Steels (AHSS) use in the automotive industry , including Complex-Phase (CP) steels that have a good combination of strength and ductility. However , despite the potential benefits of its higher mechanical strength (800 MPa), autoparts manufactured of CP steel are submitted to welding process with consumables with much lower level of mechanical strength. In order to offer an option to rationalize the use of this material in terms of welded joint, it were investigated joint performance of a pulsed GMAW welding process using ER70S-6 (class 70 psi or 482 MPa UTS) and ER110S-G (class 110 psi or 760 MPa UTS) consumables to join samples of CP-800 hot rolled steel (class 800 MPa UTS) with the same welding commercial parameters used nowadays. For this they were performed tensile, impact, hardness and metallographic tests in adequate welding samples. The results obtained in this work point to a better performance by using the ER110S-G consumable, but due to the lack of penetration in 4.0 mm thick plates it is recommended to use this consumable, under the same conditions of consumable welding ER70S-6 only on sheets up to 2.0 mm.

- by Willy Ank Morais
- •
- Welding Metallurgy, AHSS

Heat Affected Zone (HAZ) simulation by Gleeble is a useful method for evaluating welding process parameters to improve the toughness of weld HAZ by optimizing process parameters. The HAZ Toughness in low alloy steels is strongly influenced by the welding parameters (as HAZ microstructure is influenced by the heat input and cooling rate). In the present work different regions of weld HAZ of API 5L X52 steel have been simulated by using Gleeble @ 3800 Thermal-Mechanical Simulator. Two cooling rates (t) 10 s to simulate low heat input 8/5 (LHI) welding conditions without preheating, (t) 40s to simulate high heat input (HHI) welding were used. 8/5 Charpy V-notch impact tests were conducted on the simulated as well as on the base material at room temperature (25º C) and at-40º C. Results showed that HHI simulated coarse grain HAZ (CGHAZ) region attributed highest Impact energy of 300 J in comparison to 199 J of base material at 25º C. In HAZ regions, lowest room temperature toughness was observed in sub critical HAZ (SCHAZ) for both HHI and LHI conditions. Lowest impact energy at-40º C was observed in fine grained HAZ (FGHAZ) for both HHI and LHI conditions. Hardness test showed that LHI samples exhibited slightly higher hardness than HHI condition and the hardness profile for HAZ regions was similar for both HHI and LHI conditions.

Almalyk Mining and Metallurgical Plant plans to increase copper production to 400 thousand tons by 2029. Almalyk Mining and Metallurgical Combine (AGMK) plans to increase copper production to 400 thousand tons in 2020-2028, follows from the decree of the President of Uzbekistan Shavkat Mirziyoyev of May 26. According to the document, the project for expanding the production of non-ferrous metals at AGMK is divided into two stages. In 2020-2025, the plant plans to build an open pit at the Yoshlik-I deposit, as well as a new copper-processing plant (MOF) with a processing capacity of 60 million tons of ore per year. According to the calculations of the plant, it is planned to build a factory of such capacity for the first time in the CIS. For its implementation at AGMK, similar productions were studied at copper quarries in Chile and Peru. As Gazeta.uz was informed at the plant, "the uniqueness of the new factory will be in the use of a rational scheme for the enrichment of minerals, which, among other things, will increase the production of molybdenum and gold". The resolution approved the proposal of the AMMC to attract the Russian Renaissance Heavy Industries (a subsidiary of the Turkish Ronesans Holding) for the construction of the MOF. Two contracts will be signed with the company-for the execution of engineering works and design until the end of 2020, as well as for the supply of equipment on a turnkey basis. The implementation of the first stage will make it possible to increase the output of copper at the plant to 290 thousand tons, gold-up to 38 tons, silver-up to 203 tons. In February of this year, during the visit of Shavkat Mirziyoyev to Turkey with Ronesans Holding, agreements were reached on the implementation of projects in metallurgy, medicine and real estate in Uzbekistan worth about $ 8 billion. In particular, the modernization of the AMMC provides for the attraction of funds for $ 4.1 billion. The second stage of the project (2022-2028) involves the expansion of the Yoshlik-I open pit capacity and the construction of another MPF, already the fourth at the AGMK, to process 50 million tons of ore per year. This will increase the production of cathode copper-up to 400 thousand tons per year, gold-up to 50 tons, silver-up to 270 tons.

Исследование относится к переработке металлсодержащих отходов металлургического производства с использованием отходов вторичной переплавки алюминиевых материалов. Процесс осуществляется в шлаковой ковш при 1250 о С с получением бедного штейна и шлака. Это исследование позволит повысить интенсивность протекания процессов возгонки летучих металлов и восстановления железа и меди, повысить степень утилизации отходов металлургического производства. Ключевые слова: отходы металлургического производства, пирометаллургия, рециклинг, обеднение шлака.
Annotation. The study relates to the processing of metal-containing wastes of metallurgical production using wastes of aluminum producing plant. The process is carried out into the metallurgical ladle during 1250 о С with recovering depleted matte and slag. This study will increase the intensity of the processes of sublimation of flying metals and reduction of iron and copper, increase the degree of utilization of metallurgical waste.
Annotatsiya. Mazkur tadqiqot tarkibida metall saqlagan chiqindilarni alyuminiyli xomashyolarni ikkilamchi eritishdan olingan chiqindisi bilan birga qayta ishlab metall olish jarayoniga asoslangan. Jarayon metallurgik kovshlarda olib borilib harorat 1250 о С ni tashkil etadi va natijada metallga nisbatan kambag'allashgan shlak va shteyn olinadi. Ushbu tadqiqot haydash yo'li bilan olinadigan uchuvchan metallarni olish jarayonini jadallashtirishga va temir hamda misni tiklashga, metallurgiya chiqindilarini utilizatsiya qilish darajasini oshirishga yordam beradi. Kalit so'zlar: metallurgiya sanoati chiqindilari, pirometallurgiya, retsikling, shlakni kambag'allashtirish.

Comminution as an energy-intensive operation must be economically feasible for a meaningful trade in mineral resource. Therefore, the energy required to grind one tonne of an ore from a given feed particle size to a specified product particle size is a critical material property. This study evaluates the resistance of Ningi Graphite Ore to grinding using coal as a reference ore. Ore samples were extracted, homogenized, and transported to the laboratory. Crushing and grinding were done under standardized conditions using pulverizer and ball mill respectively. Fractional sieving was carried out using automatic sieve shaker. From Gates-Gaudin-Schuhmann Expression, particle size analyses of the mill feeds and products indicate the mesh grinds to be 415µm and 168µm for the test sample, and 2659µm and 178µm for the reference ore sample. The study shows that approximately 39.77Kwh of energy is required to reduce one tonne of Ningi Graphite ore from 80% passing of 415.43µm size to 80% passing of 167.83µm.

- by Olabode Akinyele and +1
- •
- Mineral Processing, Minerals Engineering, Casting, Welding Metallurgy

Lead-free perovskites are a class of promising optoelectronic materials that emerged recently as a nontoxic and stable alternative to lead halide perovskites. Herein, we report the growth and properties of a Cs4FeBiBr10 single crystal, an example of a new-type A4BB′X10 lead-free metal halide perovskite. High-quality single crystals were grown by a solution temperature-lowering method, and a needle shaped crystal with dimensions up to 4 mm × 1 mm × 1 mm was obtained. The black colored product crystallized in orthorhombic symmetry with Pnma space group as analyzed by single crystal XRD. The existence of Bi octahedra and Fe tetrahedra in the crystal lattice indicates the unique feature of the A4BB′X10 perovskite. The Cs4FeBiBr10 single crystals absorb light across the UV–visible region with an optical band gap of 1.62 eV. Temperature-dependent photoluminescence measurements indicate that the Cs4FeBiBr10 single crystals show photoluminescence emission over a wide range of the spectrum covering UV, green, and red regions. The discovery of the new-type A4BB′X10 family enriches the categories of lead-free perovskites and provides more choices of optically active materials for optoelectronic applications.

- by Zahid Mehmood
- •
- Welding Metallurgy
- by Samir Rabia
- •
- Welding Technology, Welding Engineering, Welding and Joining, Welding

The present study elaborately discussed the effect of different modes of metal transfer (i.e., short circuit mode, spray mode and pulse mode) on grain structure and direction of grain growth in low nickel austenitic stainless steel weld metals. Electron backscattered diffraction (EBSD) analysis was used to study the grain growth direction and grain structure in weld metals. The changes in grain structure and grain growth direction were found to be essentially varied with the weld pool shape and acting forces induced by modes of metal transfer at a constant welding speed. Short circuit mode of metal transfer owing to higher Marangoni force (Ma) and low electromagnetic force (Rm) promotes the lowerweld pool volume(Γ) and higherweld pool maximumradius (rm). Short circuit mode also shows curved and tapered columnar grain structures and the grain growth preferentially occurred in <001> direction. In contrast, spray mode of metal transfer increases the Γ and reduces the rm values due to very high Rm and typically reveals straight and broad columnar grain structures with preferential growth direction in <111>. In the pulse mode of metal transfer relatively high Ma and Rm simultaneously increase the weld pool width and the primary penetration which might encourage relatively complex grain growth directions in theweld pool and cause a shift of major intensity from <001> to <111> direction. It can also be concluded that the fusion zone grain structure and direction of grain growth are solely dependent on modes of metal transfer and remain constant for a particular mode of metal transfer irrespective of filler wire used.

- by Dr. Manidipto Mukherjee and +1
- •
- Mechanical Engineering, Phase Transformations, Microstructure, Metallurgy

In this study, a study on welding aluminum weldings with techniques such as TIG welding, MIG welding, Friction Stir welding, Laser Beam welding is compiled. Problems such as porosity, weld seam cracks and unstable arc that may occur as a result of the mentioned welding techniques have been investigated. The main purpose of this study is to examine the weldability of aluminum alloys and the causes and solutions of damage during or after welding. Apart from this purpose, information about the welding of aluminum alloys with other materials can be obtained. The effects of welding parameters on obtaining smooth welding products are mentioned. At the same time, the effect of the internal structure and chemical components of the alloys used on the welding process is not ignored.

- by Ahmet Enes Önder
- •
- Welding and Joining, Laser Welding, Aluminum, Aluminium Alloys

Методические указания составлены на основании типовых и рабочих программ по курсу «Теория гидрометаллургических процессов». Данное методическое указания написан на основе предмета "Теория гидрометаллургических процессов" и содержит в своем составе текст лекций, практических занятий и других материалов. В нем рассматриваются такие темы как, общие сведения о термодинамике электролитных растворов, термодинамика простого выщелачивания, термодинамика процессов химического выщелачивания, кинетика и механизм процессов выщелачивания, методы ускорения процессов выщелачивания, кинетика и механизм процессов выщелачивания самородков, оксидов и сульфидов металлов, основы процессов экстракции, основы ионообменных процессов, а также основы выделения металлов и их соединений из водных растворов.

Proceso de soldadura FCAW

- by Gianfranco Esquivel Luque
- •
- Welding Metallurgy

Physical Vapor Deposition (PVD) - surface coating technology used for decorative coating, tool coating, and other equipment coating applications. The basic mechanism - an atom by atom transfer of material from the solid phase to the... more

Physical Vapor Deposition (PVD) - surface coating technology used for decorative coating, tool coating, and other equipment coating applications.
The basic mechanism - an atom by atom transfer of material from the solid phase to the vapor phase and back to the solid phase, gradually building a film on the surface to be coated.

- by Ratan Peru
- •
- Welding Metallurgy

Dunyoda ishlab chiqariladigan misning 80 % miqdori pirometallurgik
usulga toʻgʻri keladi. Shu jumladan, Bizning mamlakatimizda ham mis eritish zavodida pirometallurgik usuldan keng foydalaniladi. Bu usul oʻzining qulayliklari bilan birgalikda bir qancha kamchiliklarga ham ega. Shulardan biri mis ishlab chiqarishda juda katta miqdorda chiqindi-shlaklarning hosil
boʻlishidir.

- by ABRAHAM SILVA HERNANDEZ and +1
- •
- Welding Technology, Welding Metallurgy, Resistance Spot Welding
- by Aong J
- •
- Welding and Joining, Welding, Welding Metallurgy, WELDING METALLURGY SECOND EDITION
- by gargouri abdelaziz
- •
- Welding Metallurgy

A laser beam welding process via heat conduction was applied to join DC01 steel with aluminum (Al)in overlap conﬁguration without ﬁller wire. The effect of the applied laser power (1.7, 1.8, 2.1, and2.4kW) on the formation and evolution of the interfaces between steel and Al was analyzed. Twointermetallic compounds were found at the interface, namely, one adjacent to the steel layer (Al
5
Fe
2
)and one close to the solidiﬁed Al (Al
13
Fe
4
). The thickness of the intermetallic reaction layer increaseswith laser power, while the morphology of its individual components evolves due to differences inaccumulated thermal cycles. Correlations between simulations and measurements show that the peaktemperature has signiﬁcantly stronger inﬂuence on the thickness of the intermetallic reaction layerthan cooling time and the integral of temperature over the time. Shear/tensile strength tests reveal thatall the specimens fail in the Al heat affected zone

- by Dierk Raabe
- •
- Electron Backscatter Diffraction (EBSD), Laser Welding, Welding Metallurgy, EBSD
- by Hassan Shaaban
- •
- Welding Metallurgy

Olmaliq kon-metallurgiya kombinati (OKMK) singari dunyoning aksariyat korxonalarida xomaki misni ishlab chiqarishning klassik
pirometallurgik sxemasi qoʻllaniladi. Bunga koʻra, sulfidli mis rudalari dastlab
flotatsion usulda boyitilib, tarkibida 16 – 20 % mis tutgan konsentrat olinadi.
Olingan misli konsentrat yuqori haroratda termik qayta ishlash maqsadida
metallurgik pechlarga yuklanadi. Metallurgik zavodlarda misli xomashyolarni qayta ishlashga moʻljallangan bir necha xil eritish pechlari mavjud. Ularga Yalligʻ qaytaruvchi, Kislorod-mashʼalali va Vanyukov kabi eritish pechlarini misol tariqasida keltirish mumkin. Bu eritish pechlarining ishlash prinsiplari har xil boʻlishiga qaramay olinadigan mahsulotlari bir-biriga oʻxshash boʻladi, yaʼni
mahsulot sifatida misli shteyn (30 – 50 % Cu), shlak va sanoat gazlari hosil boʻladi. Oraliq mahsulot – misli shteynni konvertorlash jarayoniga beriladi, u yerda havo kislorodi ishtirokida shteyn tarkibidagi keraksiz elementlarni oksidlantirish yoʻli bilan misni tozalab xomaki mis olinadi (96 – 98 % Cu). Soʻngra xomaki misni olovli tozalash jarayonida anod qoliplarga quyib
elektroliz jarayoniga yuboriladi va natijada yuqori sifatli misli katodlar olinadi
(99,99 % Cu).

In order to meet the demand for lighter and more fuel efficient vehicles, a significant attempt is currently being focused toward the substitution of aluminum for steel in the car body structure. It generates vital challenge with respect to the methods of joining to be used for fabrication. However, the conventional fusion joining has its own difficulty owing to formation of the brittle intermetallic phases. In this present study AA6061-T6 of 2 mm and HIF-GA steel sheet of 1 mm thick are metal inert gas (MIG) brazed with 0.8 mm Al–5Si filler wire under three different heat inputs. The effect of the heat inputs on bead geometry, microstructure and joint properties of MIG brazed Al-steel joints were exclusively studied and characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), electron probe micro analyzer (EPMA) and high resolution transmission electron microscopy (HRTEM) assisted X-ray spectroscopy (EDS) and selective area diffraction pattern. Finally micro-structures were correlated with the performance of the joint. Diffusion induced intermetallic thickness measured by FESEM image and concentration profile agreed well with the numerically calculated one. HRTEM assisted EDS study was used to identify the large size FeAl 3 and small size Fe 2 Al 5 type intermetallic compounds at the interface. The growth of these two phases in A2 (heat input: 182 J mm −1) is attributed to the slower cooling rate with higher diffusion time (~61 s) along the interface in comparison to the same for A1 (heat input: 155 J mm −1) with faster cooling rate and shorter diffusion time (~ 24 s). The joint efficiency as high as 65% of steel base metal is achieved for A2 which is the optimized parameter in the present study.

- by Dr. Sushovan Basak and +1
- •
- Welding Technology, Aluminium Alloys, Welding Metallurgy, Zinc Coated Steel

Reliability centered maintenance (RCM) has a key role in the quality system of thermal power plants. Electricity production is definitely not only production of a product, but also becomes a customer service. Reliability is the top quality tier of this service. Incorporation in the Integrated energy system means fast transformations of organization on all levels. The reliability of modern generation components basically influences the efficiency and capacity of a power plant as a whole. This paper presents the results of RCM practice on Unit Two of The Thermal Power Plant ″Nikola Tesla -B″, 2x600 MW, Yugoslavia. RCM implementation on current problems during exploitation emphasized problems with the boiler tubing system. The methodological approach included outages analyses, marking of the most significant ones, determination of main causes of damage (determination of the material exhaustion state based on expert analyses), application of adequate remaining life assessment methodology and finally the recommendations. Based on these analyses, certain technical solutions were performed and as a result, the mean time between failures of the plant increased, as well as its reliability. According to cost efficiency, RCM methodology presented the most effective cost-benefit method for reliability upgrade.

- by Milos Djukic
- •
- Materials Engineering, Materials Science, Quality Management, Materials Chemistry

The metal 3-D printing market is currently dominated by high-end applications, which make it inaccessible for small and medium enterprises, fab labs, and individual makers who are interested in the ability to prototype and additively manufacture final products in metal. Recent progress led to low-cost open-source metal 3-D printers using a gas metal arc welding (GMAW)-based print head. This reduced the cost of metal 3-D printers into the range of desktop prosumer polymer 3-D printers. Consequent research established good material properties of metal 3-D printed parts with readily-available weld filler wire, reusable substrates, thermal and stress properties, toolpath planning, bead-width control, mechanical properties, and support for overhangs. These previous works showed that GMAW-based metal 3-D printing has a good adhesion between layers and is not porous inside the printed parts, but they did not proceed far enough to demonstrate applications. In this study, the utility of the GMAW approach to 3-D printing is investigated using a low-cost open-source metal 3-D printer and a converted Computer Numerical Control router machine to make useful parts over a range of applications including: fixing an existing part by adding a 3-D metal feature, creating a product using the substrate as part of the component, 3-D printing in high resolution of useful objects, near net objects, and making an integrated product using a combination of steel and polymer 3-D printing. The results show that GMAW-based 3-D printing is capable of distributed manufacturing of useful products for a wide variety of applications for sustainable development.

- by Joshua Pearce and +1
- •
- Engineering, Materials Science, Design, Digital Fabrication

Ushbu uslubiy ko‘rsatma 5310300 “Metallurgiya” yo‘nalishi bo‘yicha bakalavr tayyorlashda o‘qitiladigan “Gidrometallurgiya jarayonlari nazariyasi” fani dasturi asosida tuzilgan va kafedra majlisida tasdiqlangan. Laboratoriya ishlarini bajarish uchun uslubiy ko‘rsatma “Metallurgiya” yo‘nalishida ta’lim olayotgan bakalavriat talabalari uchun mo‘ljallangan bo‘lib, shuningdek, yo‘nalish magistrantlari o‘zlarining ilmiy-tadqiqot ishlari yuzasidan tajribalar o‘tkazishda foydalanishlari mumkin.

The monograph presents theoretical approaches and concepts, analytical reviews, practical solutions in specific areas of metallurgy.
The publication may be interesting to Uzbek and foreign scientists, managers and specialists of factories and metallurgical organizations, engineers, technologists, teachers, masters and students of higher educational institutions.
Responsibility for the authenticity and accuracy of citations, names, titles and other information, as well as for compliance with intellectual property laws lies with the authors of published materials.

- by Sergio Mnez
- •
- Welding Metallurgy
- by niyazican yılmaz
- •
- Welding Engineering, Welding Metallurgy
- by Anna Valverde
- •
- Welding Metallurgy

Uslubiy qo‘llanmada gidrometallurgiya jarayonlarining nazariy asoslariga tayangan holda bu jarayonlarda uchraydigan kimyoviy hamda termokimyoviy qonuniyatlar asosida ma’ruzalar matni ko‘rsatib o‘tilgan. Muhim gidrometallurgik jarayonlar: eritmalarda uchraydigan qonuniyatlar, moddalarning ionlarga parchalanishi, tanlab eritish jarayonlarining asosiy termodinamik ko‘rsatkichlari, аsosiy va keng tarqalgan gidrometallurgik jarayonlarning mexanizmi va kinetikasining ajralib turadigan xossalari keltirilgan bo‘lib, jarayonlarni intensivlashtirishning asosiy yo‘llari bayon etilgan.

In the present work, AISI 304 stainless steel sheets are laser welded in butt joint configuration using a robotic control 600 W pulsed Nd:YAG laser system. The objective of the work is of twofold. Firstly, the study aims to find out the effect of incident angle on the weld pool geometry, microstructure and tensile property of the welded joints. Secondly, a set of experiments are conducted, according to response surface design, to investigate the effects of process parameters, namely, incident angle of laser beam, laser power and welding speed, on ultimate tensile strength by developing a second order polynomial equation. Study with three different incident angle of laser beam 89.7 deg, 85.5 deg and 83 deg has been presented in this work. It is observed that the weld pool geometry has been significantly altered with the deviation in incident angle. The weld pool shape at the top surface has been altered from semispherical or nearly spherical shape to tear drop shape with decrease in incident angle. Simultaneously, planer, fine columnar dendritic and coarse columnar dendritic structures have been observed at 89.7 deg, 85.5 deg and 83 deg incident angle respectively. Weld metals with 85.5 deg incident angle has higher fraction of carbide and d-ferrite precipitation in the austenitic matrix compared to other weld conditions. Hence, weld metal of 85.5 deg incident angle achieved higher micro-hardness of $280 HV and tensile strength of 579.26 MPa followed by 89.7 deg and 83 deg incident angle welds. Furthermore, the predicted maximum value of ultimate tensile strength of 580.50 MPa has been achieved for 85.95 deg incident angle using the developed equation where other two optimum parameter settings have been obtained as laser power of 455.52 W and welding speed of 4.95 mm/s. This observation has been satisfactorily validated by three confirmatory tests.

- by Nikhil kumar and +1
- •
- Laser, Welding Technology, Welding Engineering, Welding Metallurgy

High frequency welding is a thermo-mechanical process that relies on precise heat input as well as mechanical control as strip edges are heated and forged together to result in a seam weld. Heat input can be defined as a way of characterizing the temperature distribution at the strip edges prior to forging them together. Heat input is affected by several process variables ranging from raw material properties to welder settings and weld area setup. These are summarized in this paper, with special attention on the effects of welder frequency, welder power, line speed, and steel alloy composition on heat input and the resulting weld quality. Frequencies in the range of 100-800 kHz are considered. Data from tube mills (including general data and controlled on-the-mill experiments) and laboratory evaluations are included in this paper.

- by Lesley D. Frame and +1
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- Welding Metallurgy, High Frequency Welding
- by Dr. Manidipto Mukherjee
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- Welding Technology, Welding Engineering, Welding and Joining, Welding
- by Juan Manuel Rodríguez
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- Welding Metallurgy

Qo‘llanma metallurgiya sohasiga qiziqadigan barcha kitobxonlarga
mo‘ljallangan bo‘lib, xususan “Metallurgiya” yo‘nalishida ta’lim
olayotgan talabalarga va metallurgiya korxonalariga ishga kirmoqchi
bo‘lgan bakalavrlarga qo‘llanma sifatida tavsiya etiladi.
Qo‘llanma o‘z tarkibiga metallurgiya sohasiga tegishli savoljavoblarni, metallar haqidagi eng zarur ma’lumotlarni, sohaga oid ilmiy
yangilik va qiziqarli ma’lumotlarni hamda mamlakatimizda ishlab
chiqariladigan metallarning qisqacha texnologik jarayonlari haqidagi
qismlarni oladi.
Ushbu qo‘llanmadan “Metallurgiya” sohasi bo‘yicha dars beradigan
o‘qituvchilar ham foydalanishlari mumkin.

Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, mi-crostructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.