High-strength low-alloy steel

[2] These elements are intended to alter the microstructure of carbon steels, which is usually a ferrite-pearlite aggregate, to produce a very fine dispersion of alloy carbides in an almost pure ferrite matrix.

Zirconium, calcium, and rare-earth elements are added for sulfide-inclusion shape control which increases formability.

Bends that are parallel to the longitudinal grain are more likely to crack around the outer edge because it experiences tensile loads.

This directional characteristic is substantially reduced in HSLA steels that have been treated for sulfide shape control.

[2] They are used in cars, trucks, cranes, bridges, roller coasters and other structures that are designed to handle large amounts of stress or need a good strength-to-weight ratio.

Examples of uses include door-intrusion beams, chassis members, reinforcing and mounting brackets, steering and suspension parts, bumpers, and wheels.

The other mechanisms include solid solution strengthening and precipitate hardening from micro-alloyed elements.

[13][12] Control-rolled HSLA steels usually have higher strength and toughness, as well as lower ductile-brittle transition temperature[14] and ductile fracture properties.

Effect of micro-alloyed elements Niobium: Nb can increase the recrystallization temperature by around 100 °C,[12] thereby extending the non-recrystallization region and slowing down the grain growth.

[12] Other alloying elements are mainly for solid solution strengthening including silicon, manganese, chromium, copper, and nickel.