Production of Hotform Blanks: Heating and cooling
Hot, hotter, hot forming
The heat is on: the production process starts in the furnace, where the manganese-boron steel blanks (ThyssenKrupp Steel Europe MBW® 1500) are first heated to temperatures of 880 to 950 degrees Celsius to impart excellent forming behavior. An aluminum-silicon coating protects the hot forming steels from scaling during their passage through the furnace. On request, this steel can also be used without coating.
During subsequent hot forming, the blanks are formed into parts in a special stamping press and simultaneously cooled at a rate of more than 30 Kelvin per second, resulting in an extremely hard microstructure. The parts generally achieve strengths of 1,500 MPa, a level which is not attainable with conventional steel grades.
Weld seam without coating
The protective coating of aluminum and silicon needed for hot forming can cause weaknesses in the weld. To counter this we have developed a laser decoating unit, which uses a pulsating solid state laser to remove the coating to a width of 1.5 mm on each side of the weld gap. This makes the seam stronger and permits the part to be hot formed without any problems. This innovation has helped us extend our leading position with regard to equipment technology.