Strong yet easy to mould: Dual-phase steel

Dual-phase steel, which includes both DP steel and the newer DH steel, is a special form of high-strength steel. It has a unique microstructure that is characterised by very high strength combined with relatively good forming properties. These steels are particularly suitable for forming in the stretch forming range.

Production, grades and applications of dual-phase steel

The production of dual-phase steel begins with careful selection and pre-treatment of the raw material with specific chemical elements. This raw material is then prepared for the subsequent heat treatment to produce the dual-phase structures using various processes, including rolling and annealing.

The corresponding microstructure of the steel is set in certain temperature ranges in the rolling process. The special heat treatment of the low-carbon steel produces ferrite and martensite in two phases - hence the name dual-phase steel. This process ensures that the steel has both high strength (due to the martensite phase) and good formability (due to the ferrite phase).

Common grades are CR330Y590T-DP, CR440Y780T-DP and CR780Y980T-DP. The DH versions of these grades are also frequently used as they offer even better formability. The numerical values of the respective grades indicate the yield strength and tensile strength. Our mentioned grades can be found, for example, in VDA 239-100, but also in the factory standards of well-known car manufacturers.

Dual-phase steel is in great demand in various industries due to its properties, such as its high tensile strength. Typical examples of applications include car body parts in the automotive industry, where the high strength combined with a relatively low weight is an advantage. In the construction industry, steel is used for structural elements that require both strength and flexibility.