During the years, there have been opposite opinions about the use of slag retainers in the Roof & Shell panels. Even though the retainers help to retain the slag, when you weld them to the pipe there is a grain growth in the steel microstructure that weakens the pipe’s strength in the weld heat affected area; normally the thermal fatigue stress cracks start appearing in the neighborhood of these seam welds on the pipes exposed to temperature. So, adding slag…