The use of hot formed 22MnB5 steel with an aluminium-silicon (AS) coating is well established for high strength automotive parts to combine weight reduction and passenger safety. Recent developments aim to increase the material strength for further weight saving and to improve the ductility. Especially an improved ductility makes hot formed parts suitable for additional applications, such as parts with higher energy absorption or even axially loaded parts. thyssenkrupp Steel Europe AG has developed new hot stamping grades. With an increased strength of about 1900 MPa, the MBW-K 1900 allows the application of even lighter parts compared to 22MnB5. Due to the increased strength level, delayed fracture has to be evaluated. Furthermore, the recommended parameters for processing MBW-K 1900 are regarded. A high crash performance of a material implies a high strength, while the material still shows no cracking during folding or heavy bending of the automotive part. This is the basis for the development of tribond 1200 and tribond 1400. As a new concept for hot stamping, tribond 1200/1400 are composite materials, which bond two outer layers of a ductile 500 MPa steel grade with a high strength 1500 MPa steel core layer. Both grades are already well known as monolithic steels MBW 500 and MBW 1500 for hot stamping. An aluminium-silicon coating allows tribond 1200/1400 to be processed in the same way as AS coated 22MnB5. Nevertheless tribond 1200/1400 show a reduced susceptibility to hydrogen embrittlement in the 4-point bending test compared to 22MnB5. By their improved crash behaviour, tribond 1200/1400 enable the manufacturing of more kinds of hot formed parts such as longitudinal beams. An advanced simulation method takes the composite structure of tribond 1200/1400 into account to evaluate the crash behaviour.

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To provide a high quality of forged products, a homogeneous distribution of material properties has to be achieved inside the ingot. As the properties are not visible from the outside, an online monitoring during the forging process is required. By using modern measuring equipment and fast calculation models, the equivalent strain, temperature and average grain size in the core fibre of a forging ingot can be calculated parallel to the process. Software implementing the fast calculation models has been established and connected to the measuring system of two different open die forging presses. Two experimental forging processes with ten passes have been performed (20 ton steel ingot, 750 kg Ni-base alloy ingot). Parallel to the process, the current strain, temperature and average grain size in the centre of the ingot are visualised in the graphic user interface and recorded by the process monitor. It was shown that the calculation speed is high enough to allow online capability. After finishing the process, the developed software can further be used to analyse in detail the impact of every single stroke or pass on the whole process. Additionally, information like minimum or maximum grain size or recrystallized fraction is calculated and can be used to get insight into the process and optimize its design. Comparing the metallographically measured average grain size from experiment with the grain size estimated by the process monitor, the average deviation of three measured points is less than 13 %.

To reduce the failure of dies by abrasive wear, mechanical fatigue and thermal fatigue in closed-die forging usually measures like nitriding, deposition of ceramic layers by Physical Vapour Deposition (PVD), Chemical Vapour Deposition (CVD) or deposition welding are used. However, after some time wear appears and the dies have to be replaced. A new concept implements sheet metal die covers, which are placed on the die engraving during forging and will absorb abrasive wear, thermal and mechanical load. The inexpensive cover will be replaced quickly by a new one after it is worn-out. This concept is regarded in a first numerical and experimental study by comparing a covered die (C) and an uncovered die (U) for the production of the same part. A one-time use of the die cover showed a reduction of the peak temperature by 140 K and of the temperature amplitude by 37 %. The temperature reduction and the increase of inner radii of the engraving to fit the 1mm thick die cover doubled the expected die life time. The experiment showed that the soft deep drawing steel DC04 is not suitable in the current case for a die cover and a higher strength sheet metal should be applied.

While 22MnB5 with aluminium silicon (AS) coating was established as the quasi-standard in press hardening many years ago, the need for steels that offer even higher strength is growing. These needs include corrosion protection of the automotive component and scale prevention during processing in hot forming lines. However, the processing of AS coated ultra-high strength steels involves demands for the furnace atmosphere. Reducing the hydrogen susceptibility and increasing the material strength at the same time was the driving force for the development of MBW 1900 + AS Pro. The paper focuses on the process stability of this steel concerning furnace and stamping parameters as well as the hydrogen induced cracking resistance under different dew points in the furnace atmosphere. In addition, the potential by means of different partial press hardening processes is presented. With tailored tempering, locally heated tools can be used to achieve soft areas in the part. Furthermore, the application potential of MBW 1900 + AS Pro in tailor welded blanks is shown.