Investigation into the Impact Toughness of API 5L X80 Steel Weldments and its Relationship with Safe Welding Procedures

Carbos, Thiago Rodrigues; Jorge, Jorge Carlos Ferreira; Souza, Luís Felipe Guimarães de; Bott, Ivaní de Souza; Mendes, Matheus Campolina

doi:10.1590/1980-5373-mr-2020-0363

Cited by 7 publications

(2 citation statements)

References 55 publications

(108 reference statements)

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“…Steels that comply with API 5L or (American Petroleum Institute Oil Pipe Standard) EN ISO 3183 are steels produced according to the criteria set by the American Petroleum Institute or European Standards and are used in oil and natural gas pipelines [1]. The characteristic of these steels can be expressed as being resistant to welding, shaping, and impacts due to their high strength and low alloy in accordance with the limits specified in the relevant quality descriptions.…”

Section: Introductionmentioning

confidence: 99%

Investigation on impact and DWTT resistance at low temperatures in Nb and Ti micro alloy steels

Bölükbaşı¹,

Keçeci²

2023

Pamukkale J Eng Sci

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Depending on the climatic conditions in which they are used, new generation petroleum pipe steels come up with the need for high strength and excellent toughness. During the transportation of oil and natural gas, these steels should be at the highest level of impact resistance along with high hardness. In recent years, the general test temperatures, such as 0 o C, tend to be lower minus degrees. In this study; (American Petroleum Institute X70 Quality) API X70, impact, (dropweight tear test) DWTT, and strength were modeled on rolls with thicker than 10 mm. In addition, the necessary parameters for high impact strength at low temperatures were determined by modeling. After the steel production and rolling with the specified parameters, mechanical tests and microstructure examinations were carried out. In order to determine the effect of strength and toughness on mechanical properties, different test sets were prepared for chemical analysis and rolling parameters. The differences in the product microstructure and test results of the titanium level and different holding times and thermomechanical and conventional rolling were investigated. The impact energy values of the materials produced with different process parameters were examined using large data sets. As a result, it has been determined that the particles produced by the thermomechanical rolling method and the particles are the most minor and homogeneously dispersed in the microstructure meet the expectations in terms of material quality.Yeni nesil petrol boru çelikleri, kullanıldıkları iklim koşullarına bağlı olarak yüksek mukavemet ve mükemmel tokluk ihtiyacı ile karşımıza çıkmaktadır. Petrol ve doğalgazın taşınması sırasında bu çeliklerin yüksek sertlik ile birlikte darbe dayanımının da en üst seviyede olması gerekmektedir. Son yıllarda, 0 o C gibi genel test sıcaklıkları, eksi derecelerden daha düşük olma eğilimindedir. Bu çalışmada (American Petroleum Institute X70 Quality) API X70, darbe, (düşürme-ağırlığı yırtılma testi) DWTT ve mukavemet; 10 mm'den kalın rulolar üzerinde modellenmiştir. Ayrıca düşük sıcaklıklarda yüksek darbe dayanımı için gerekli parametreler modelleme ile belirlenmiştir. Belirtilen parametrelerde çelik üretimi ve haddeleme sonrasında mekanik testler ve mikroyapı incelemeleri yapılmıştır. Mukavemet ve tokluğun mekanik özellikler üzerindeki etkisini belirlemek için kimyasal analiz ve haddeleme parametreleri için farklı test setleri hazırlanmıştır. Titanyum seviyesi ve farklı bekletme süreleri ile termomekanik ve konvansiyonel haddelemenin mamul mikro yapı ve test sonuçlarında yarattığı farklılıklar araştırıldı. Farklı proses parametreleri ile üretilen malzemelerin darbe enerji değerleri büyük veri setleri kullanılarak incelenmiştir. Sonuç olarak termomekanik haddeleme yöntemi ile üretilen ve tanelerin en küçük ve mikro yapı içerisinde homojen dağılmış olanların malzeme kalitesi olarak beklentileri karşıladığı tespit edilmiştir.

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Section: Introductionmentioning

confidence: 99%

Investigation on impact and DWTT resistance at low temperatures in Nb and Ti micro alloy steels

Bölükbaşı¹,

Keçeci²

2023

Pamukkale J Eng Sci

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“…The microstructures in the HAZ and fusion zone (FZ) are different from those in the base metal (BM), and the transformations of these microstructures cause changes in mechanical properties as well as welding cracks, which significantly decrease welding safety [ 3 , 4 ]. The coarse grains and formation of martensite cause a reduction in toughness, and martensite–austenite (M/A) mixtures act as crack initiation sites, producing local brittle zones (LBZs) [ 5 , 6 , 7 ]. Therefore, predicting the phase transformation in a welded joint during the welding process is necessary to maximize welding safety.…”

Section: Introductionmentioning

confidence: 99%

A Methodology for Predicting the Phase Fraction and Microhardness of Welded Joints Using Integrated Models

Song

2023

Materials

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Understanding the phase transformation and fraction affected by thermal changes is imperative for ensuring the safety of a welded joint. This study proposes a methodology for predicting the phase transformation and fraction of a welded joint using an integrated model. The integrated model includes a heat transfer model and procedures for predicting phase fraction and microhardness. The heat transfer model was developed to simulate the heat transfer in a welded joint and obtain the thermal cycles. The procedure consists of obtaining the peak temperature, austenite fraction, prior austenite grain size (PAGS), and t8/5 (the cooling time between 800 and 500 °C). A database was constructed based on the continuous cooling transformation (CCT) diagram using PAGS and t8/5 as the variables. The phase fraction was then predicted by considering the PAGS with t8/5 from the database. The predicted phase fraction and microhardness were in good agreement with those determined experimentally, demonstrating the reliability of the methodology. This methodology provides a more realistic understanding of phase transformation and facilitates the prediction of the phase fraction and microhardness under various welding conditions that have experimental limitations.

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Multiscale Characterizations of Local Properties for Girth Welds of X70 and X80

Cao

Zhao³

et al. 2022

Adv Eng Mater

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As pipeline design standards require the parameters of mechanical properties, it is crucial to characterize local properties of grith weld. Consequently, the multiscale characterizations based on indentations are performed to study the local properties of these typical zones: weld metal, heat affected zone (HAZ), fusion zone, and base material. The microhardness is measured for entire girth welds of X70 and X80, and the nanohardness is also obtained to analyze the differences in typical zones of girth welds. Subsequently, the yield strength and ultimate tensile strength in the typical zones of girth welds are characterized by spherical indentation method to analyze the distributions of strength and local hardening capacity. Furthermore, the microstructures of girth welds for X70 and X80 in terms of typical zones are studied to analyze the responses of local properties. Results show that the hardness of cap, filler, and root layers for X70 follows the sequence of cap>filler>root, while that of X80 follows the sequence of filler>cap>root. The softening effect of HAZ is existed in the girth weld of X70. The low hardness and strength in root layer are attributed to polygonal ferrite.

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Investigation into the Impact Toughness of API 5L X80 Steel Weldments and its Relationship with Safe Welding Procedures

Cited by 7 publications

References 55 publications

Investigation on impact and DWTT resistance at low temperatures in Nb and Ti micro alloy steels

Investigation on impact and DWTT resistance at low temperatures in Nb and Ti micro alloy steels

A Methodology for Predicting the Phase Fraction and Microhardness of Welded Joints Using Integrated Models

Multiscale Characterizations of Local Properties for Girth Welds of X70 and X80

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