Weld Metal Hydrogen Assisted Cold Cracking in High Strength Low Alloy Steels

oleh Lenka Kuzmikova, Frank Barbaro, John Norrish, Huijun Li

Penerbit - CBMM Technology Suisse, University of Wollongong

Kategori - Novel Am

High strength low alloy steels have provided significant benefits to the safe and economic fabrication of modern steel structures. Steel consumption has been optimized but most importantly the associated reduction in carbon content has reduced the risk of hydrogen assisted cold cracking (HACC) in the weld heat affected zone (HAZ) and thus improved fabrication procedures. Unfortunately the issue of HACC is now more likely to manifest itself in the weld metal. Although there are reliable procedures available to avoid HACC in the HAZ there is no such guidance for HACC in the weld metal. The role of hydrogen in this phenomenon is crucial and until now little has been known about the distribution of hydrogen following completion of welding. This investigation, using different weld consumables and novel hydrogen analysis techniques has provided an insight to the diffusion of hydrogen. It is shown that an austenitic weld metal, or a weld metal that transforms after the HAZ will provide a sink for hydrogen and so reduce the level of hydrogen in the adjacent HAZ. It is concluded that this mechanism may contributes to an increased risk of HACC in a susceptible weld metal.

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