Advanced High Strength Steels (AHSS), ≥ 550 MPa TS: Advanced high strength steels (AHSS) usually refer to steel types that are strengthened through phase transformation, and the structure contains martensite, bainite and/or residual Austenite. Including duplex steel, TRIP steel, composite steel and martensitic steel, etc. The strength and plasticity of advanced high-strength steel are far superior to ordinary high-strength steel. The combination of high strength and high formability makes it widely used in construction, offshore platforms, mechanical lifting, footbridges, foundation engineering, etc.

In this area, quenched and tempered (Q&T) and thermo-mechanically rolled high-strength products are most popular.

Due to the properties mentioned above, high-strength steel delivered in the quenched and tempered condition is widely used in heavy engineering, construction and other industries. Heavy-duty above-ground, underground and hoisting machinery manufacturing accounts for more than 70% of quenched steel plate consumption.

High-strength steel can significantly extend the service life of equipment and machinery, reduce the frequency of machine replacement and repair, and reduce downtime.

The advantages of thermomechanically rolled products come from their key properties such as low carbon equivalent, high strength and high impact toughness. Compared with conventional steel, TMСР rolled products show greater efficiency during processing: reduced costs for welding consumables, no preheating of the steel and additional heat treatment, reduced overall steel strength of the structure, shortened project implementation time.

High strength steel is mainly used in construction and different engineering industries.

The use of high-strength thermo-mechanically rolled steel instead of ordinary structural steel greatly reduces the steel strength of civil structures due to the use of columns with thinner walls and flanges, but the compressive strength properties are the same. For example, using TMCP boards to make welded columns of modern commercial high-rise buildings can save 20-30% of steel. When used in an open truck structure, TMCP panels reduce its weight by 30-35% (and correspondingly increase its payload capacity).

High-strength steels delivered in thermomechanically rolled conditions are manufactured in accordance with EN 10025-4, DSTU EN 10025-4 and EN 10149-2 and other regulatory documents and under the manufacturer’s own brand.

Quenching is the heating of steel above the phase transformation temperature followed by rapid cooling (in water, oil, polymer or ether mixtures, etc.) at a rate above the critical speed. The heating temperature and cooling medium are selected according to the chemical composition of the steel and the required structural conditions. After quenching, steel acquires a non-equilibrium metastable structure with high strength (up to 2500 MPa), hardness (up to 600-650 Vickers), wear resistance and brittleness. Quenching can involve specifically heating the steel after rolling or using the heat of rolling (called direct quenching).

Thermo-mechanically controlled processes (rolling; TMCP) require careful control of sheet temperature and deformation during rolling. The properties obtained after TMCP cannot be achieved by normalizing or other types of heat treatments. The final fine-grained microstructure of the steel is obtained by microalloying, rolling within a temperature range and controlled cooling (as well as accelerated cooling using an air-water mixture).

Due to their high strength, weldability and resistance to embrittlement, TMCP steel products can be used in structures with operating temperatures up to -50°C and guaranteed impact strength values.