Ultrahigh-strength steels at elevated temperatures

Keränen, Lassi; Kangaspuoskari, M.; Niskanen, Juhani

doi:10.1016/j.jcsr.2021.106739

Cited by 20 publications

(3 citation statements)

References 22 publications

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“…Currently, AHSS is in its third generation. Many studies that involve welding effects have been developed along with the evolution of new grades of AHSS with critical mechanical properties and a focus on essential properties, such as strength and toughness [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…The development of UHSS and its applications has brought different perspectives to conventional production methods, primarily due to the unique characteristics of the product/structures to which UHSS is applied. These characteristics may create not only advantages but also difficulties that need to be discussed before these new materials are widespread in order to prevent future barriers [11][12][13][14][15]. According to Jenney et al [16], in certain manufacturing processes (including welding), the improvement of materials plays an essential role, mainly affecting properties, such as hardness and weldability, that need to be enhanced.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of GMAW Process Parameters in Ultra-High-Strength Steel Based on Prediction

Netto

Bayock

Kah

2023

Metals

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Ultra-high-strength steel (UHSS) is a complex and sophisticated material that allows the development of products with reduced weight but increased strength and can assist, for example, in the automotive industry, saving fuel in vehicles and decreasing greenhouse gas emissions. Welding UHSS has a certain complexity, mainly due to the higher alloys and heat treatments involved, which can result in a microstructure with higher sensitivity to welding. The primary purpose of the current work was to select the best parameters of the gas metal arc welding (GMAW) for welding the S960 material based on prediction methods. To achieve the expected results, a finite element analysis (FEA) was used to simulate and evaluate the results. It was found that the welding parameters and, consequently, the heat input derived from the process greatly affected the UHSS microstructure. Using FEA and estimating the extension of the heat-affected zone (HAZ), the peak temperature, and even the effect of distortion and shrinkage was possible. With an increase in the heat input of 8.4 kJ/cm, the estimated cooling rate was around 70 °C/s. The presence of a softening area in the coarse grain heat-affected zone (CGHAZ) of welded joints was identified. These results led to an increase in the carbon content (3.4%) compared to the base metal. These results could help predict behaviors or microstructures based on a few changes in the welding parameters.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of GMAW Process Parameters in Ultra-High-Strength Steel Based on Prediction

Netto

Bayock

Kah

2023

Metals

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“…Ultra-high strength structural parts have been widely used in automotive, aircraft, buildings and so on for energy-saving and emission reduction [1]. At present, the hot stamping process is a popular technology for producing the ultra-high strength parts from boron steels [2].…”

Section: Introductionmentioning

confidence: 99%

Performance Comparison of Zn-Based and Al–Si Based Coating on Boron Steel in Hot Stamping

Chen

Cao

et al. 2021

Materials

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The coatings of boron steels play an important role in affecting the quality of hot stamping parts, so it is important to evaluate the hot stamping performance of coatings before designing processes. Taking the U-type hot stamping part of boron steel as research objects, the surface quality, microstructure and temperature variation of samples with GA (galvannealed), GI (galvanized) and Al–Si coatings were observed and analyzed to evaluate the anti-oxidation, forming and quenching performances of different coatings. The results show that all the GA, GI and Al–Si coatings could provide good oxidation protection and also act as the lubricants for avoiding the friction damage of sample substrates and die-surface. But the different compositions of GA, GI and Al–Si coatings will contribute the different colors. Under the same deformation degree, the Al–Si coating can provide the best substrate protection and the GI coating will induce cracks in the substrate because of the liquid metal-induced embrittlement phenomenon. There is no significant difference between the quenching performances of GA, GI and Al–Si coatings, and the thermal conductivity of the GI coating is slightly better than Al–Si and GA coatings.

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Flow and hardening behavior in the heat-affected zone of welded ultra-high strength steels

Afkhami,

Amraei,

Javaheri

et al. 2024

Weld World

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The applications of thermomechanically processed ultra-high strength steels (UHSS) are rapidly increasing, and welding these UHSSs seems inevitable in steel structures. However, welding heat causes unwanted microstructural transformations in the heat-affected zone (HAZ). Due to the localized nature of these changes throughout the HAZ, evaluating the true stress–strain values of these localized HAZ subzones is essential to improve the accuracy of analytical or numerical models. Hence, this study utilized experimental thermal simulations to replicate HAZ subzones of two types of UHSSs, i.e., direct-quenched S960 and quenched-and-tempered S1100, and employed tensile test in conjunction with digital image correlation to plot the true stress–strain and hardening curves of the subzones. Both UHSSs manifested similar trends but with various fluctuations in their hardening capacities throughout their HAZ subzones. Next, hardening parameters from Hollomon, Voce, and Kocks-Mecking approaches were extracted by fitting the experimental results with the semi-empirical equations. For both UHSS types, the Voce approach, on average, was more accurate in modeling the plastic deformation. Also, hardening parameters achieved via the Voce approach’s fittings agreed with the parameters from Kocks-Mecking plots; this consistency pointed to the predictability of the plastic flow and hardening behavior of both UHSS types. According to the microstructural investigations, the hardening behavior of the investigated HAZ subzones depended on two types of microstructure constituents: ferritic and lath-like features. Ferritic features dominantly governed the plastic flow and hardening near the fusion line, while by getting distant from the fusion line, the lath-like features became more dominant.

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Ultrahigh-strength steels at elevated temperatures

Cited by 20 publications

References 22 publications

Optimization of GMAW Process Parameters in Ultra-High-Strength Steel Based on Prediction

Optimization of GMAW Process Parameters in Ultra-High-Strength Steel Based on Prediction

Performance Comparison of Zn-Based and Al–Si Based Coating on Boron Steel in Hot Stamping

Flow and hardening behavior in the heat-affected zone of welded ultra-high strength steels

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