Loading...

Role of tandem submerged arc welding thermal cycles on properties of the heat affected zone in X80 microalloyed pipe line steel

Moeinifar, S ; Sharif University of Technology

2139 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.jmatprotec.2010.10.011
  3. Abstract:
  4. The influence of thermal cycles on the properties of the coarse grained heat affected zone in X80 microalloyed steel has been investigated. The thermal simulated involved heating the X80 steel specimens to the peak temperature of 1400 °C, with different cooling rates. The four-wire tandem submerged arc welding process, with different heat input values, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between the bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone region. The fractional area of M/A particles due to different cooling rate was the main factor in increasing of the hardness values in the coarse grained heat affected zone. The Charpy absorbed energy of specimens was assessed using Charpy impact testing at -50 °C. The martensite/austenite constituent's size such as mean diameter and length are important factors influencing Charpy impact properties of coarse grained heat affected zone. The micro crack nucleation may occur from M/A particles at the intersection of prior-austenite grain boundaries. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values
  5. Keywords:
  6. Heat affected zone ; Mechanical properties ; Microstructure ; Pipeline ; Steel ; Welding ; Austenite grain boundaries ; Bainitic ferrite ; Charpy absorbed energy ; Charpy impact ; Coarse grained heat affected zone ; Cooling rates ; Crack initiation sites ; Four-wire ; Fractional area ; Growth mechanisms ; Hardness values ; Heat affected zone regions ; Heat input ; Martensite/austenite constituent ; Mean diameter ; Microalloyed Steel ; Peak temperatures ; Submerged arc ; Thermal cycle ; X80 steel ; Austenite ; Carbon dioxide arc welding ; Charpy impact testing ; Cooling ; Cracks ; Electric welding ; Ferrites ; Grain boundaries ; Grain size and shape ; Stringers ; Submerged arc welding ; Submerged melt welding ; Thermal cycling ; Mechanical properties
  7. Source: Journal of Materials Processing Technology ; Volume 211, Issue 3 , 2011 , Pages 368-375 ; 09240136 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0924013610003201