Equivalent material properties of the heat-affected zone in welded cold-formed rectangular hollow section connections

Yan, R.; Mela, Kristo; Yang, Fei; El Bamby, H.; Veljkovic, M.

doi:10.1016/j.tws.2022.110479

Equivalent material properties of the heat-affected zone in welded cold-formed rectangular hollow section connections

Title

Equivalent material properties of the heat-affected zone in welded cold-formed rectangular hollow section connections

Author

Yan, R. (TU Delft Steel & Composite Structures)
Mela, Kristo (Tampere University)
Yang, Fei (Chang'an University)
El Bamby, H. (TU Delft Steel & Composite Structures)
Veljkovic, M. (TU Delft Steel & Composite Structures)

Date

2023

Abstract

A welded connection consists of three main material zones, the base material (BM), the heat-affect zone (HAZ), and the weld metal (WM). The strength of HAZ depends on the BM grade and manufacturing process, electrode grade, and welding parameters. Under certain conditions, HAZ has the lowest material strength, especially for high-strength steel. Therefore, a semi-empirical methodology is proposed to establish a constitutive model of HAZ necessary for predicting the fracture position of welded connections. This methodology is based on an engineering approach to consider HAZ as an isotropic and homogeneous material, with no consideration of different volumetric fractions of microstructures within a HAZ. The equivalent material properties of HAZ in butt-welded hollow section connections were investigated experimentally and numerically. Hardness tests and microstructure investigations were conducted to determine the boundaries of material variations and the width of HAZ. The stress–strain relationship of HAZ was established and calibrated based on tensile coupon tests and finite element analyses. Using the calibrated HAZ stress–strain relationship, the effect of transverse constraint imposed by the adjacent and stronger material (BM and WM) on HAZ was evaluated in the welded connections. Finally, the new methodology of a semi-empirical constitutive model based on the Swift model was used to propose equivalent characteristics of HAZ as a function of the mechanical properties of BM for a specific welding procedure considered in the project.

Subject

Butt weld
Constitutive model
Heat-affected zone
High-strength steel
Transverse constraint

To reference this document use:

http://resolver.tudelft.nl/uuid:d3100b35-f855-42f8-a628-44c7c14d2a14

DOI

https://doi.org/10.1016/j.tws.2022.110479

ISSN

0263-8231

Source

Thin-Walled Structures, 184

Part of collection

Institutional Repository