Mechanical Property Characterization for X80 Pipeline Steel Welds Using Indentation

  • Program
  • Room 2F East
  • September 12 2018
  • 9:00 am - 9:25 am

GMAW is often favoured to join pipeline steel since it is a productive process for long distance line pipe joining. However, due to the large thickness of the line pipe steels, multipass welds are necessary to fill the joint. The multiple thermal cycles during welding will create heterogeneity through the weld metal (WM) and heat effect zone (HAZ), which make it difficult to characterize the mechanical properties using conventional techniques such as tensile testing. In this work instrumented indentation technique was employed in order to characterize mechanical properties of the WM and HAZ across the joint. Vickers indentation was used to determine the hardness and modulus of elasticity for different zones across the weld. In addition, nearly flat tip indenter was used to determine yield strength based on the load-displacement response for each zone. The results were correlated with the microstructures for each zone in order to explain the observed mechanical response based on microstructure characterization. The results indicate a strong correlation between yield strength and hardness, however the implications for replacing conventional all-weld metal testing with indentation will be discussed.