| High strength steels (HSS) of yield strength between 500 . 900 MPa are used in industries such as shipbuilding and automobile manufacturing and for applications like offshore structures due to their advantageous physical and mechanical properties, which surpass those of conventional steels. Although the strength levels of HSS make structural weight reduction possible, and corresponding reduction of transportation and other manufacturing costs, the usability of high strength steels is negatively affected by issues such as a susceptibility to cracking and heat affected zone (HAZ) softening due to the effects of welding heat input. These quality problems can have a detrimental effect on the structural integrity of HSS welded structures. This paper critically reviews the usability of high strength steels from a structural integrity viewpoint drawing attention to the key issues involved. A decision-making tool for risk assessment based on the analytical hierarchy process (AHP) is presented and its suitability for evaluation of structural integrity risk in welded HSS structures. Challenges regarding HSS usability from the weldability and service performance perspectives are related to factors such as heat input, cooling rate and type of filler material; and weld geometry and crack propagation, respectively. The potential of an on-line welding process monitoring system incorporating AHP as part of the risk assessment process is noted. Additionally, the study identifies a need for further research on neuro-fuzzy network systems as an optimization mechanism for mitigating potential flaws in welding usability of HSS and its variants (advanced high strength steels, and ultra-high strength steels). |
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