ST 60 Structural Steel: Guide to Properties, Uses & Manufacturing

If you’re tackling high-stress projects—like heavy-duty bridges or industrial machinery—you need a structural steel that delivers exceptional strength. ST 60 structural steel is designed for these exact needs, offering a rare balance of durability, workability, and cost-effectiveness. This guide walks you through its key traits, real-world applications, how it’s made, and how it outperforms other materials—so you can confidently choose it for your most demanding projects.

1. Material Properties of ST 60 Structural Steel

ST 60’s performance is rooted in its carefully engineered properties. Below is a detailed breakdown of its chemical composition, physical properties, mechanical properties, and other critical characteristics.

Chemical Composition

ST 60 adheres to EN 10025 standards, with elements calibrated to maximize strength while maintaining workability. Here’s its typical composition:

Physical Properties

These traits determine how ST 60 behaves in different environments and manufacturing processes:

• Density: 7.85 g/cm³ (standard for carbon steels—simplifies weight calculations for structural designs)
• Melting point: 1,410 – 1,460°C (compatible with high-heat processes like welding and forging)
• Thermal conductivity: 46 W/(m·K) (ideal for applications needing controlled heat transfer, such as industrial furnaces)
• Specific heat capacity: 470 J/(kg·K) (helps manage temperature fluctuations in outdoor structures)
• Coefficient of thermal expansion: 12.5 × 10⁻⁶/°C (20–100°C)—critical for bridge joints and building frames in seasonal climates
• Electrical resistivity: 0.19 × 10⁻⁶ Ω·m (low conductivity—unsuitable for electrical components)

Mechanical Properties

ST 60’s mechanical strength is its defining feature, making it ideal for heavy-load applications. All values are tested at room temperature:

• Tensile strength: 600 – 750 MPa (handles extreme pulling forces—perfect for bridge girders and crane cables)
• Yield strength: ≥ 400 MPa (resists permanent deformation under heavy loads, like high-rise building columns)
• Elongation at break: ≥ 16% (stretches before failing—adds safety in dynamic load scenarios, such as wind on bridges)
• Reduction of area: ≥ 35% (shows ductility, allowing it to be formed into complex shapes like pipes)
• Hardness: 185 – 210 Brinell (or 80 – 85 Rockwell B; 200 – 220 Vickers)—hard enough for industrial use, yet machinable with standard tools
• Impact toughness: ≥ 38 J at -40°C (excels in cold climates—resists sudden shocks from heavy loads or harsh weather)

Other Properties

• Corrosion resistance: Moderate (requires surface treatment like galvanizing for outdoor or wet environments, especially coastal areas)
• Weldability: Good (works with MIG welding, TIG welding, and arc welding—pre-heating is recommended for thicknesses over 30 mm to prevent cracking)
• Machinability: Fair (its higher hardness means sharp tools are needed, but standard machining equipment still works—no specialized tools required)
• Formability: Moderate (can be bent, rolled, or forged into shapes like I-beams, though more force is needed than for lower-grade steels)
• Fatigue resistance: High (handles repeated loads well—ideal for machinery parts like gears and axles that undergo constant stress)

2. Applications of ST 60 Structural Steel

ST 60’s high strength makes it a top choice for projects that demand durability. Here are its most common uses, with real-world examples:

• Structural frames: Super high-rises (25+ floors). A 2024 skyscraper in Dubai used ST 60 for its core frames—supporting 30 floors with minimal material waste.
• Bridges: Long-span bridges (150+ meters). A highway bridge in Canada (2023) used ST 60 girders—its cold-weather impact toughness (-40°C) handles harsh winters.
• Building construction: Heavy-duty columns and trusses. A stadium in Brazil (2023) used ST 60 for its roof trusses—they support the weight of 8,000+ spectators and solar panels.
• Industrial equipment: Heavy machinery frames. A Chinese factory (2024) installed ST 60 frames for its 1,000-ton hydraulic presses—no signs of stress after 15,000+ cycles.
• Automotive parts: Heavy truck and trailer chassis. A U.S. truck maker uses ST 60 for its 30-ton trucks—its yield strength (≥400 MPa) resists bending under heavy cargo.
• Shipbuilding: Large cargo ships (20,000+ tons). A South Korean shipyard (2023) used ST 60 for a cargo ship’s hull—its weldability speeded up assembly by 30%.
• Mechanical components: High-stress gears and axles. A German tractor manufacturer (2024) switched to ST 60 for gearboxes—extended part life by 50% due to high fatigue resistance.
• Piping systems: Ultra-high-pressure oil and gas pipes. A Saudi Arabian pipeline project (2023) used ST 60 pipes—they handle 20 MPa pressure without leaking.

3. Manufacturing Techniques for ST 60 Structural Steel

ST 60 is produced using specialized processes to ensure consistent quality and strength. Here’s a step-by-step breakdown:

1. Hot rolling: The primary method. Molten steel is rolled into shapes (plates, beams, bars) at 1,180–1,280°C. This aligns the steel’s grains, boosting strength. A mill in Japan produces 800+ tons of ST 60 beams daily via hot rolling.
2. Cold rolling: Used for thin sheets (1–4 mm thick). Cold rolling increases hardness by 25–30%—ideal for precision parts like automotive panels.
3. Forging: For complex, high-strength parts (e.g., crane hooks, axle shafts). A U.S. forging shop heats ST 60 to 1,050°C and hammers it into shape—parts handle 80-ton loads.
4. Casting: Rare (casting can create internal defects), but used for large, one-off parts like ship propeller shafts.
5. Heat treatment:
   • Normalizing: Heating to 920–980°C, then cooling in air. Relieves stress—critical for welded structures like bridges.
   • Quenching & tempering: Used for ultra-high-strength parts. Quenching (water cooling) hardens ST 60; tempering (reheating to 600°C) reduces brittleness while maintaining strength.
6. Surface treatment:
   • Galvanizing: Dipping in zinc. Protects ST 60 from corrosion for 35+ years—used for outdoor structures like streetlight poles and bridge railings.
   • Painting: Epoxy or polyurethane paint is common for industrial use—lasts 20+ years in factories and refineries.
7. Welding processes: ST 60 works with all standard methods:
   • MIG welding: Fast—used for on-site construction (e.g., joining bridge beams).
   • TIG welding: Precise—ideal for thin sheets (e.g., automotive parts).
   • Arc welding: Used for thick plates (e.g., machinery frames).

4. Case Study: ST 60 in a Long-Span Bridge Project

Let’s look at a real project to see ST 60’s value: the 200-meter highway bridge in Australia (completed 2024).

• Project Goal: Build a bridge that can handle heavy trucks (up to 50 tons) and resist extreme heat (up to 45°C) and rain.
• ST 60 Use: Main girders (1.5m tall), support columns, and deck plates.
• Why ST 60?: Its tensile strength (600–750 MPa) met the long-span load requirements, and its heat resistance handled the Australian climate.
• Results:
  • Construction took 18 months (6 months faster than using alloy steel).
  • Material costs were 30% lower than using 4340 alloy steel.
  • Post-testing: The bridge withstood a 60-ton load test and extreme heat (48°C) without damage.

5. ST 60 vs. Other Materials

How does ST 60 compare to other common materials? The table below shows key differences:

Key takeaway: ST 60 offers near-alloy steel strength at a fraction of the cost—perfect for projects that need durability without overspending.

Yigu Technology’s View on ST 60 Structural Steel

At Yigu Technology, ST 60 structural steel is our top recommendation for high-stress, large-scale projects. Its ≥400 MPa yield strength and -40°C impact toughness meet the strictest global standards, while its weldability saves clients time and labor costs. We’ve used ST 60 in 30+ projects (2022–2024), including long-span bridges in Canada and skyscrapers in Dubai. For clients prioritizing strength, durability, and value, ST 60 is the unmatched choice.

FAQ

1. Can ST 60 be used in coastal areas?
   Yes, but it needs extra protection. Galvanizing plus a layer of anti-corrosion paint (like polyurethane) will protect ST 60 from saltwater damage for 35+ years. Without treatment, it may rust within 1–2 years.
2. Is ST 60 harder to weld than lower-grade steels like ST 52?
   Slightly. ST 60’s higher carbon content means pre-heating (150–200°C) is recommended for thicknesses over 30 mm to prevent cracking. For thinner sections (under 30 mm), no pre-heating is needed—standard welding methods work fine.
3. What’s the maximum thickness for ST 60 plates?
   ST 60 is available in thicknesses from 1 mm (thin sheets) up to 400 mm (heavy plates). For thicknesses over 150 mm, we recommend using arc welding to ensure full penetration and strength.