Thanks to Domex from SSAB, Rotem increased safety and reduced weight on their passenger trains – an ambitious move to use such an advanced application in an industry often considered “conservative.” In 2006, Rotem visited SSAB’s stand at the InnoTrans exhibition and shortly after contacted SSAB regarding the use of Domex for their trains.
“Before we tried Domex advanced high strength steel, mild steel plate was usually used in the train industry,” says Gilsoo Chang, principal research engineer at Rotem’s R&D Center, “but finally we found that the Domex strip product was the best choice.”
Domex 550 and 700 were applied to the main structural parts of the car body. Compared to mild steel, Domex steel is stronger and thus reduces the weight of each part by around 20 percent. “The weight reduction on trains also offered high value to our end users as it brought about fuel savings and reduced the environmental impact,” confirms Chang. Meanwhile, the lightweight design delivered even higher impact energy absorbing performance due to Domex high strength steel’s high yield values. As passenger trains have extremely high safety requirements, this protection feature is critical.
“During our more than four years’ cooperation, we have been very impressed with the professional and considerate technical support we have received from SSAB,” says Chang.
SSAB’s experts from welding, customer service and product development have actively supported Rotem at meetings with their end users. SSAB has also conducted several welding and impact tests and developed a thicker Domex solution to help Rotem apply corrosion resistant steel for the trains serving coastal areas. Today, SSAB is Rotem’s main supplier of imported steel for passenger trains and other overseas projects as the company plans to extend the application of Domex to other areas.