Martensitic steel: excellent formability-to-strength ratio

What is the definition of martensitic steel?

When austenite iron is very rapidly quenched, the austenite is transformed into a very hard crystalline microstructure called “martensite.”

The martensitic transformation begins when the austenite reaches the martensite start temperature (M_s) and continues until the lower transformation temperature (M_t) is reached. In general, the higher the percentage of conversion to martensite, the stronger the resulting martensitic steel. These steels undergo post-quench martensitic tempering to improve their ductility, so that even MS steels with very high strength levels can be cold-formed using processes like cold-roll forming.

To produce cold-rolled martensitic steel (aka MS or MART), a cold-rolled steel strip is fed into a continuous annealing line (CAL). In the CAL, the material is annealed, water-quenched, and tempered. The austenite formed in the CAL, when rapidly quenched, is transformed into martensite. The CAL’s tempering operation provides the ultra-high strength steel with improved ductility.

Docol^® martensitic grades have less than 2% alloying elements, providing good weldability.

• Extremely high yield strength (R_p0,2) and tensile strength (R_m).
• Superior energy absorption and impact strength for anti-intrusion zones.
• Ideal for vehicle lightweighting.
• Cold formability in bending, stamping, and roll-forming — including 3D forming.
• Martensitic steel is significantly more cost-effective than aluminum: using optimized design profiles, MS steels can deliver high-strength performance that is similar to aluminum and at the same weight.