AusFerrite

Purpose and goal

The aim of the project with two steel manufacturers Smålands Stålgjuteri and Ovako (one is medium-sized) and four OEM Epiroc, Indexator, Olofsfors och Rototilt (three are medium-sized) has been to develop and evaluate ausferritic steels and ADI in high performance applications, where concurrently very high strength and very high toughness are required. The project has led to deeper cooperation within value chains primarily in Sweden, but also to the evaluation by a foreign OEM. After in-depth testing, several OEMs are considering implementing ausferritic steels in their products.

Expected results and effects

Cost-effective heat treatment processes, also leading to improved mechanical properties with less variation, have begun to be developed for both ausferritic steels and ADI. Extensive material data for ausferritic steels has been produced through tensile testing, Charpy V, fracture toughness KJIC and rotary bending fatigue. For example, an ausferritic steel with strength >2 GPa (Rm=2052 ±18 MPa) can simultaneously have two-digit fracture elongation (A5=10.7 ±0.2 %). Implementation is expected in various applications where both high strength and high toughness are required.

Planned approach and implementation

Development of ausferritic steels with medium C and high Si content could, via 1-tonne ingots from steel casting foundry followed by forging into single billets and rolling, be upscaled to continuous casting of >100 tonne of billets. Ausferritic steels and ADI have been evaluated both by participating OEMs and by existing customers to the steel manufacturers. Examples include various applications that combine high contact pressures or wear with impact stress, as well as in lighter suspension components which thus require increased fatigue strength.