High-strength structural steels

High-strength structural steels

• Structural steels with a yield strength exceeding 355 MPa.
• Typical yield strength values range between 500 MPa and 1300 MPa.
• Impact toughness requirement: no less than 27J at -40°C.
• Advantage: allows for lighter construction without compromising strength compared to conventional structural steels.

Design considerations for high-strength steels

• Elastic deflection.
• Increased fracture risk with thinner dimensions.
• Geometric irregularities and weld seam placement to reduce fatigue fracture risk.

Distinction between high-strength and ultra-high-strength steels

Lies in the microstructural differences.

Ultra-high-strength structural steel in plate form

• After rolling, plates undergo controlled tempering with rapid cooling to direct phase transformation.
• Categorized by microstructure: dual-phase, complex-phase, multi-phase, TRIP, martensite, and press-hardened steel.

Weight savings with ultra-high-strength steels

• Used in structures requiring weight reduction without compromising strength.
• Examples: automotive safety components like B-pillar reinforcements, side-impact beams, and bumpers.

Applications

• Crane arms.
• Mining and construction equipment.
• Bridge structures.
• Agricultural machinery.