Steel is the backbone of modern infrastructure and will remain to be the most important construction metal in the future. Steel is widely used in applications were a balance of strength, ductility and impact toughness is required to reach safety standards. Today, a large share of steel forgings is produced from quench and tempering (Q+T) steels, as these steels fulfill the requirements mentioned above. However, the quench and tempering heat treatment, is an energy-intensive procedure, which raises the demand for a steel concept with similar properties and a lean heat treatment, especially in the context of the ambitious goal to reach CO2-emission neutrality by 2050.

Recently a new type of martensitic steels was introduced, which achieve their final properties through air cooling from the forging heat. These materials were pushed to market maturity and are now standardized under the European material number 1.5132. The steels are alloyed with a significant amount of manganese (> 4wt.%) and additional elements (Si, Al, B, Nb) to suppress the diffusion-controlled phase transformation during air-cooling. However, as the addition of alloying elements is obviously higher as in standard Q+T steels (> 5wt.% compare to < 2wt.%) the reasonable question occurs if the CO2-emissions associated with the production of the alloying elements equalizes the emission reductions achieved by the reduction of the heat treatment.

In order to address this issue, the properties as well as the caused CO2-emissions need to be addressed. Firstly, the results of the first industrial production of this steel grade will be discussed, including mechanical properties, fatigue behavior as well as micro- and nanostructure investigations. Secondly, the CO2-emissions on material, process and product level will be assessed and compared to a reference steel grade.