MW Italy

Establishment of a correlation between fracture toughness and fatigue resistance automotive wheels’ Dual-Phase600 steel

MW is a division of the CLN Group, renowned as a market leader in producing steel wheels for passenger cars and light commercial vehicles. With eight production plants, MW possesses an impressive yearly production capacity of approximately 22 million pieces. The division has a strong global presence, with its headquarters and three production plants located in the EU.

Their main engineering and research department is situated at MW Italy’s headquarters, where one of the focus of research is to improve the fatigue performances of wheels through the implementation of new materials and processes.one 

Motivation

MW Italy, the beneficiary of the ToughSteel Open Call, needed to establish a correlation between fracture toughness and fatigue resistance for the material utilized in the production of automotive wheels. The study concentrated on Dual-Phase600 steel, considering various batches and sheet thicknesses.

This investigation aimed to gain valuable insights into the material’s performance under demanding conditions, ensuring enhanced safety and durability of the wheels. MW Italy sought to optimize the manufacturing process and advance the quality of its automotive wheels.

Thanks to ToughSteel we were able to define a link between fracture toughness and the fatigue behaviour of the steel wheel. We demonstrated that we could take fracture toughness as a parameter to predict fatigue behaviour

Davide Ronco, Research & Development Manager, MW Italy

Case study results

Four DP600 steels for wheel applications have been analysed in this study.

The materials were two batches from 1 supplier (Supplier A) and two other batches from a different supplier (Supplier B). MW performed their conventional fatigue tests to assess the fatigue behaviour of the wheels manufactured with the different materials. The fracture toughness of these steels was successfully evaluated and a quite good correlation between we and fatigue behaviour was established.

The differences in fatigue behaviour between the two steel suppliers were also captured by fracture toughness results. This difference is difficult to predict by FEM and other tensile properties.

The analysis of steel fracture properties can be an instrument that can help to predict the behaviour on fatigue behaviour of wheels.  Other analyses are needed to improve the correlation, also considering different failure modes, e.g. the fatigue resistance of, punched, trimmed or severely deformed areas.

Visual description of the MW Italy case study to investigate the relationship between fracture toughness and fatigue behaviour of DP600 steels for wheels applications.