What is s420mlo 1.8830 steel material?

S420MLO (1.8830) is a high-strength, thermomechanically rolled (+M) weldable structural steel grade specified in EN 10225-1:2019, the European standard for weldable structural steels used in fixed offshore structures. This grade is part of Group 2 steels in the standard and is designed for applications requiring excellent toughness, weldability, and corrosion resistance in marine environments, such as offshore platforms, jackets, and topsides. It is suitable for plates and hollow sections, with a focus on low-temperature performance down to -40°C.

The steel is produced to withstand harsh offshore conditions, including low temperatures, high loads, and corrosive saltwater exposure. Gangsteel supplies S420MLO plates in thicknesses up to 100 mm, ensuring compliance with EN 10225-1 through rigorous testing and certification. Our plates are optimized for welding without preheating in thinner sections and offer superior fatigue resistance for long-term durability in offshore projects.

Chemical Composition of S420MLO 1.8830 Steel

The chemical composition is tightly controlled to ensure low carbon equivalent for weldability and microalloying for fine-grain structure. Below is the ladle and product analysis (max % unless specified) for delivery condition +M.

*Notes: Residual elements like As (≤0.03%), Sb (≤0.010%), Sn (≤0.020%), Pb (≤0.010%), Bi (≤0.010%), Ca (≤0.005%), and B (≤0.0005%) are limited. Al:N ratio ≥2:1 for grain refinement (Al minimum does not apply if other N-binding elements are used).

Mechanical Properties of S420MLO 1.8830 Steel

S420MLO offers high yield and tensile strength with good elongation and impact resistance at low temperatures. Properties vary by thickness for delivery condition +M.

*Notes: Mid-thickness Charpy tests required for t >40 mm at -30°C instead of -40°C. 1 MPa = 1 N/mm². Elongation for maximum thickness.

Heat Treatment Guide for S420MLO 1.8830 Steel

S420MLO is supplied in thermomechanically rolled (+M) condition, which combines controlled rolling with accelerated cooling for fine-grain structure and high strength.

• Post-Weld Heat Treatment (PWHT): Test welds at (580 ± 20)°C or agreed temperature, soaking 1 h per 25 mm thickness (min 4 h). Heating rate ≤ (5500/t)°C/h or 55°C/h (t = thickness in mm). Cooling to 400°C ≤ (6875/t)°C/h or 55°C/h; below 400°C in still air.
• Hot Forming: Not recommended; if necessary, re-thermomechanical treatment may be required to restore properties.
• Welding: Low CEV ensures weldability; no preheating for thin sections. Follow EN 1011-2.

Gangsteel provides plates optimized for these processes.

Applications of S420MLO 1.8830 Steel

S420MLO is used in fixed offshore structures:

• Offshore Platforms: Jackets, topsides, and risers.
• Marine Equipment: Subsea pipelines and hollow sections.
• Oil & Gas: Fixed installations in harsh marine environments.

For higher strength needs, consider S460MLO or en 10025 3 s420nl normalized structural steel plate.

Equivalent Grades to S420MLO 1.8830

Why Choose Gangsteel for S420MLO 1.8830 Steel?

With state-of-the-art mills and a commitment to ISO-certified quality, Gangsteel delivers S420MLO plates tailored to your specifications. Stocked in various sizes and ready for immediate export worldwide. For detailed pricing and availability, contact our sales team today.

Summary

S420MLO 1.8830 steel is a thermomechanically rolled high-strength grade from EN 10225-1, with 350–420 MPa yield, 530–680 MPa tensile, and 50 J impact at -40°C. Its low-carbon composition (CEV not specified, but low P/S) and fine-grain structure make it ideal for offshore platforms and marine structures. S420MLO from Gangsteel ensures compliance and durability for fixed offshore installations.

FAQ

What is the JIS equivalent to S420MLO 1.8830 steel?

SM490YA (JIS G 3106) is the closest equivalent, with 490 MPa tensile and similar weldability; specify offshore testing for full equivalence.

How do S420MLO and S420NL differ chemically?

S420MLO has lower C (0.14% vs. 0.20%) and stricter residual elements (e.g., As ≤0.03%, B ≤0.0005%), optimized for offshore corrosion resistance.

Are their mechanical properties identical?

S420MLO has higher tensile (530–680 MPa) and impact (50 J at -40°C) vs S420NL's 500–680 MPa and 27 J at -50°C, tailored for offshore loads.

Can S420MLO replace S420NL in offshore structures?

Yes, if EN 10225-1 is specified, S420MLO offers superior offshore properties; consult codes for substitution.

What if I need a higher-strength offshore grade?

For S460MLO, consider SM520B (JIS); contact Gangsteel for cross-standard guidance