20th International Forgemasters Meeting - IFM 2017

Large forgings for power generation, ship shafts and plastic extrusion dies require large high quality ingots. In 2008, Ellwood Quality Steels (EQS) implemented a 2-ladle, interrupted pouring process to produce 70 Mton bottom poured ingots. Commissioning of the new 90 MN North American Forgemasters (NAF) open die press in early 2016 generated the need for much larger ingots. To produce ingots greater than the nominal heat size and maintain quality represents a challenge for a Steelmaker. It was determined that the interrupted bottom pouring process was not feasible to expand from a 2-ladle to a 4-ladle pouring process while continuing to meet quality requirements. Various methods were investigated and Sandwich Pouring was selected to be the optimal choice to produce high quality bottom poured ingots up to 165 Mton at EQS. The existing 45 Mton and 70 Mton bottom poured ingots, were scaled up using the suitable L/D ratio, hot-top volume and throat opening during the design stage of the larger ingots. Finite element analysis (FEA) software was used to model hot top configurations and insulating materials in order to achieve ideal solidification behavior. The training of the bottom pour crews took place on ingots 70 Mton and smaller with the modified teeming car and the ladle-to-ladle shroud manipulator prior to startup of the 90 MN NAF open die press. Once the 90 MN press was commissioned, the first 90 Mton (2 ladles) and 125 Mton (3 ladles) ingots were produced using the Sandwich Pouring Process. The ingots were forged on the 90 MN NAF press, located in the same complex as the EQS Melt Shop. The segregation pattern, micro cleanliness and ultra sound inspection of the steel forgings have been extensively assessed. The resulting forged pieces have been found to have low segregation, good micro-cleanliness and have met rigorous power generation ultra sound requirements. The continuing development and FEA modeling of the 165 Mton ingot(4 ladles) is also presented.