Comparing the Structure and Mechanical Properties of Welds on Ductile Cast Iron (700 MPa) under Different Heat Treatment Conditions

Gouveia, Ronny Miguel; Silva, Francisco; Paiva, Olga C.; Andrade, María de Fátima; Pereira, Lucas Augusto; Moselli, Paulo Cezar; Papis, Konrad J. M.

doi:10.3390/met8010072

Cited by 15 publications

(9 citation statements)

References 25 publications

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“…Thermal cycles are usually applied in difficult-to-weld materials, being a very useful tool to improve the weldability of these materials [39,40]. New thermal cycles for the heat treatment of grade P91 steel welded joints, produced by GTAW and using a filler metal rod (ER 90S B9-with similar composition to grade P91 steel) were developed, to improve on those that were previously developed.…”

Section: Discussionmentioning

confidence: 99%

Enhancing Heat Treatment Conditions of Joints in Grade P91 Steel: Looking for More Sustainable Solutions

Sousa

Silva

Pinho

et al. 2021

Metals

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Grade P91 is a relatively new class of steel, which has received special attention from designers because it presents extremely interesting characteristics for specific applications. This steel exhibits ideal properties for demanding applications, especially involving high temperature and pressure, being employed in facilities such as power plants and other equipment, such as heat exchangers. P91 welds usually need heat treatments, which are already parameterized in the codes. However, standardized treatments are time-consuming and harmful to the environment, as they massively consume energy. Some attempts have been made in the past to reduce the time and energy spent on these treatments. This work aims to extend this study, now presenting better solutions than those obtained previously. This work presents four new conditions for the heat treatment of joints carried out on P91 steel, with a view to reducing processing time, reducing energy consumption, and an even better balance between mechanical strength and elongation after failure. Heat treatment conditions were established in which there was a loss of about 14% in Ultimate Tensile Strength (UTS), but in which a gain of about 50% in elongation was obtained, compared to welding without any treatment, but also with 10% losses in the UTS and 30% gains in elongation when compared to the solution recommended as more correct in the codes, saving a lot of time and energy in the treatment process. Thus, these solutions may be adopted in the future with gains in terms of productivity and economic and environmental sustainability.

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Section: Discussionmentioning

confidence: 99%

Enhancing Heat Treatment Conditions of Joints in Grade P91 Steel: Looking for More Sustainable Solutions

Sousa

Silva

Pinho

et al. 2021

Metals

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“…Основними причинами, по яким неможливо отримати яюсний метал шва при зварю ванш i наплавлены чавунних деталей в промислових умовах е недосконала система розкис лення i легування його присадковим прутком [6]. Метал шва мае шдвищену твердшть низью мехашчш властивостi, що обумовлюе схильшсть до утворення мшких трiщин, я к знижують експлуатацiйну стiйкiсть зварних i наплавлених деталей.…”

Section: анал1з останшх досл1дженьunclassified

Improvement of materials for gas welding of cast iron

Kalin¹

2019

Mash

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УДОСКОНАЛЕННЯ МАТЕРЬАШВ ДЛЯ ГАЗОВОГО ЗВАРЮВАННЯ ЧАВУНУ © Кал1н М. А. Украгнська 1нженерно-тдагог1чна академ1я 1нформащя про автора: Калш М икола Андр1йович: ORCID: 0000-0002-4068-2718; svargof@gmail.com; кандидат техтчних наук; доцент кафедри штегрованих технологiй в машинобудувант та зварювального виробництва; Укранська iнженерно-педагогiчна академгя; вул. Унiверситетська, 16, м. Харшв, 61003, Украша.Метою дослщження е створення прутка для газового зварювання чавунних деталей, з покращеними мехашчними характеристиками i меншою твердютю металу шва.Недолшом вiдомих зварювальних пруткiв е висока твердiсть i низькi механiчнi властивостi металу шва. Це не дозволяе використовувати згадаш присадковi прутки для зварю вання вщповщальних конструкцiй i наплавлення деталей, що пiдлягають механiчнiй обробщ в промислових об'емах.У якосп присадкового матерiалу при газовому й електродуговому зварюваннi чавуну, використовували прутки дiаметром 8-10 мм iз чавуну марки А або Б за ГОСТ 2671-80. Як флюс при газовому зварюванш використовували буру техшчну за ГОСТ 8429-77, прожарену при температурi 300-350° С протягом 2 -х годин.В якосп легуючо! добавки РЗМ у чавунних прутках використовували ггрш i ербш. Перевiрку зварювально-технологiчних властивостей дослiдних складiв прутюв прово дили при газовому (ацетилено-кисневому) i електродуговому зварюванню високомiцного чавуну марки ВЧ 40.На пiдставi проведених випробувань зварювально-технолопчних властивостей досль дних пруткiв визначено, що оптимальним е пруток №2, що забезпечуе гарну змочувашсть зварювально! ванни рщким металом. Шлаки легкоплавкi й не утрудняють ведення процесу зварювання розробок великого обсягу. Дефекпв зварених швiв немае.Структура наплавленого металу у поверхш шва на глибинi до 1,5-2 мм перлпна з не великими дшянками аустенiту дендритно! орiентацii. Далi по висотi шва аж до лшп сплаву в структурi переважае перлiт. Включення фериту i цементиту одиничнi. Графiт кулястий середньо! величини, декiлька дрiбнiше, шж в основному металi.Твердiсть в цш зонi складае 220-229 НВ i дозволяе легко проводити мехашчну обробку зварних швiв звичайним металорiжучим iнструментом.Ключовi слова: пруток, чавун, зварювання, твердють, трiщини.Калин Н.А. «Усовершенствование материалов для газовой сварки чугуна». Целью исследования является создание прутка для газовой сварки чугунных деталей, с улучшенными механическими характеристиками и меньшей твердостью металла шва.Недостатком известных сварочных прутков является высокая твердость и низкие ме ханические свойства металла шва. Это не позволяет использовать упомянутые присадочные прутки для сварки ответственных конструкций и наплавки деталей, подлежащих механичес кой обработке в промышленных объемах.В качестве присадочного материала при газовой и электродуговой сварке чугуна, ис пользовали прутки диаметром 8-10 мм из чугуна марки А или Б по ГОСТ 2671-80. В качестве флюса при газовой сварке использовали буру техническую по ГОСТ 8429-77, прокаленную при температуре 300-350оС в течение 2-х часов.В качестве легирующей добавки РЗМ в чугунных прутка...

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“…The Ni-Fe electrodes were also studied and compared with pure Ni electrodes by Pascual et al [16], and it was concluded that the high purity Ni electrode had better results than the Ni-Fe electrodes. Therefore, welds performed with Ni electrodes have been given greater importance [22,23] due to the microstructure achieved during welding processes [24].…”

Section: Introductionmentioning

confidence: 99%

Improving the Mechanical Strength of Ductile Cast Iron Welded Joints Using Different Heat Treatments

et al. 2019

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The main advantage of welding cast iron is to recover parts by repairing defects induced by casting processes (porosities, etc.), before they enter their working cycle, as well as repair cracks or fractures when already in service. This method contributes to decreased foundry industrial waste and avoids the additional energy costs of their immediate recycling. Therefore, it is necessary to have a welded joint with similar or better characteristics than the parent material. The major problem of welding cast iron is that this material has a very high content of carbon in comparison to steel (≈3%). Therefore, when it is heated by the very high temperatures from arc welding and during its process of solidification, very hard and brittle phases originate, known as ledeburite and martensite, and appear in the partially melted zone and in the heat-affected zone. Eventually, this problem can be solved by implementing heat treatments such as preheat or post weld heat treatments under specific parameters. Therefore, in this study, the aim is to collect data about the effects of heat treatments performed at different temperatures on welded joints of high strength ductile cast iron (SiboDur® 450), and to evaluate the effects of heat treatments performed at diverse temperatures on welded joints of this type of material, using Shield Metal Arc Welding and nickel electrodes. Mechanical strength, hardness, and microstructure were analyzed, showing that the best mechanical strength in the joint (380 MPa) was obtained using two passes of E C Ni-Cl (ISO EN 1071:2015) filler metal and post weld heat treatments (PWHT) of 400 °C for two hours.

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Comparing the Structure and Mechanical Properties of Welds on Ductile Cast Iron (700 MPa) under Different Heat Treatment Conditions

Cited by 15 publications

References 25 publications

Enhancing Heat Treatment Conditions of Joints in Grade P91 Steel: Looking for More Sustainable Solutions

Enhancing Heat Treatment Conditions of Joints in Grade P91 Steel: Looking for More Sustainable Solutions

Improvement of materials for gas welding of cast iron

Improving the Mechanical Strength of Ductile Cast Iron Welded Joints Using Different Heat Treatments

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