European rail-freight wagons are typically constructed with structural steels such as ArcelorMittal’s S235JR. Although these steels exhibit good strength and corrosion resistance properties, they are heavier than modern solutions.
In 2011, ArcelorMittal’s R&D Industry division took on the challenge of finding an ultra high strength steel (UHSS) solution for rail freight wagons to improve the sustainability of freight transport by train.
ArcelorMittal’s R&D Industry engineers selected an E71-type gondola wagon as a reference. The E71 wagon is widely used across Europe and is typically built using S235JR. The empty (tare) weight of the standard E71 is around 27 tonnes. The wagon has a volume of 70 m3 and can weigh up to 80 tonnes fully loaded.
Three grades from our Amstrong® range of high-tech steels were selected for the new wagon. Amstrong® 420MC and Amstrong® 500MC are high strength low alloy (HSLA) grades while Amstrong® Ultra 700MC is an ultra high strength low alloy steel. All three have excellent strength-to-weight ratio. The empty (tare) weight of the redesigned E71 is around 18 tonnes, 33% lighter than the reference.
As damage to a wagon may occur in remote locations, the R&D engineers only selected steels that are easy to weld and can be repaired with existing equipment. Overall, material costs of the new wagon were 34% lower than for the existing E71. Although the price of the advanced steels is higher than S235JR, less steel is required. Industrial formability is also improved, leading to further cost reductions.