Welded Structural Steels for Arctic Applications
Kivinummi, Patrik (2024)
2024
Materiaalitekniikan DI-ohjelma - Master's Programme in Materials Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2024-06-17
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202406117106
https://urn.fi/URN:NBN:fi:tuni-202406117106
Tiivistelmä
This study explores the challenges and solutions associated with designing welded steel structures for Arctic applications. The Arctic environment, characterized by extreme cold and unpredictable weather conditions, presents unique obstacles for structural design and durability. Key standards, including Eurocodes and EN 13001-3-1, are examined to provide guidelines on constructing steel structures that can withstand Arctic conditions. The study looks into the transition behavior of steels in cold environments, emphasizing the transition temperature from ductile to brittle and its impact on structural integrity. Study also discusses the effect of thickness in terms of impact strength values and how these different standards take it into account.
The study also investigates the effects of welding on steel structures, highlighting the influence of the Heat-Affected Zone (HAZ) and potential issues such as brittle fractures, hydrogen-induced cracking, hot cracks, and lamellar tearing. The study provides strategies to mitigate these risks, including adjustments to welding parameters and post-weld heat treatments.
Microstructural considerations, such as grain size, are discussed in relation to their influence on transition temperature and toughness. The study emphasizes the need for balanced cooling rates during welding to optimize mechanical properties.
Experimental data reinforces theoretical insights, providing practical guidelines for designing steel structures to withstand low temperatures. This study offers a comprehensive understanding of the challenges in constructing welded steel structures for Arctic applications and presents solutions to enhance their resilience and longevity. The testing involved welding thick structural steel plates with various parameters, evaluating their impact strength, and comparing the microstructural differences between samples. Welding procedure qualification testing was also conducted to ensure the highest quality.
The research highlighted that ductility and plastic deformation capabilities are key attributes for steel structures to endure cold temperatures. Ferritic steels undergo a ductile-to-brittle shift at specific temperatures, and it's crucial that this transition temperature remains low enough to preserve ductile behavior in operational conditions. Additionally, welding can impair a structure's ductile performance, making it vital for welding to adhere to standards essential for structural endurance. The study also notes that thin steels rarely suffer from the effects of cold temperatures, while thick steels that can experience triaxial stresses do. Experiments revealed that the steel used performs well in cold temperatures, and welding parameters noticeably affect impact strength values, particularly in the HAZ area.
The study also investigates the effects of welding on steel structures, highlighting the influence of the Heat-Affected Zone (HAZ) and potential issues such as brittle fractures, hydrogen-induced cracking, hot cracks, and lamellar tearing. The study provides strategies to mitigate these risks, including adjustments to welding parameters and post-weld heat treatments.
Microstructural considerations, such as grain size, are discussed in relation to their influence on transition temperature and toughness. The study emphasizes the need for balanced cooling rates during welding to optimize mechanical properties.
Experimental data reinforces theoretical insights, providing practical guidelines for designing steel structures to withstand low temperatures. This study offers a comprehensive understanding of the challenges in constructing welded steel structures for Arctic applications and presents solutions to enhance their resilience and longevity. The testing involved welding thick structural steel plates with various parameters, evaluating their impact strength, and comparing the microstructural differences between samples. Welding procedure qualification testing was also conducted to ensure the highest quality.
The research highlighted that ductility and plastic deformation capabilities are key attributes for steel structures to endure cold temperatures. Ferritic steels undergo a ductile-to-brittle shift at specific temperatures, and it's crucial that this transition temperature remains low enough to preserve ductile behavior in operational conditions. Additionally, welding can impair a structure's ductile performance, making it vital for welding to adhere to standards essential for structural endurance. The study also notes that thin steels rarely suffer from the effects of cold temperatures, while thick steels that can experience triaxial stresses do. Experiments revealed that the steel used performs well in cold temperatures, and welding parameters noticeably affect impact strength values, particularly in the HAZ area.