AH36 ship plate is recognized as an "all-round player" in the international shipping industry. The "36" in its grade represents the minimum yield strength of 355MPa, which belongs to the mid-to-high-end level of high-strength hull steel. The material adopts the "low carbon + multi-element microalloying" design: the carbon content is ≤0.16% to ensure weldability, and the manganese content is increased to 1.20%-1.70% to enhance solid solution strengthening. At the same time, niobium (0.02%-0.05%), vanadium (0.03%-0.08%), and titanium (0.015%-0.03%) are added to form carbonitrides, and the strength and toughness are improved through the dual mechanisms of precipitation strengthening and grain refinement.
The characteristics have been significantly improved:
Mechanical properties: yield strength 355-490MPa, tensile strength 510-660MPa, -20℃ impact absorption energy ≥34J, can be stably used in the cold seas south of the Arctic Circle (minimum -30℃);
Anti-fatigue performance: no cracks after 10^6 cycles under alternating load (stress amplitude 200MPa), suitable for ship main engine base, propeller hub and other parts with severe vibration;
Corrosion resistance: through Cu (0.20%-0.40%) and Ni (0.30%-0.60%) alloying, the corrosion rate in the seawater environment of pH 4-9 is ≤0.03mm/year, which is 1/5 of ordinary carbon steel;
Welding process: supports high-efficiency welding methods such as CO2 gas shielded welding and submerged arc welding, the hardness of the heat-affected zone is ≤250HV, and no heat treatment is required after welding to meet the requirements of classification societies.
The advantages are reflected in the adaptability to complex environments:
1. Cross-regional applicability: It complies with the IMO International Ship Structural Rules (IACS UR W3) and can sail in more than 90% of the world's seas, including tropical waters with high salt fog and high-impact reef areas;
2. Lightweight structure: Under the same load, the thickness of AH36 ship plate can be 10%-15% thinner than AH32. For example, a 20,000-ton bulk carrier can reduce weight by 300 tons and increase cargo capacity by 5% by using AH36;
3. Long life cycle cost advantage: The design life is more than 25 years, and the full-cycle maintenance cost is 30% lower than that of ordinary steel, which is especially suitable for the long-term service needs of ocean-going ships.
The applications are concentrated in high-demand scenarios:
Key structures of ocean-going ships: side ribs of container ships (thickness 30-50mm), longitudinal bulkheads of tankers (25-40mm), which bear alternating loads and oil corrosion;
Special ships: bow outer plates of icebreakers (thickness 60-80mm), using AH36-Z35 (Z-direction shrinkage ≥35%) to resist layered tearing caused by ice compression;
Marine engineering equipment: frame structures of deep-sea aquaculture cages (round tubes with a diameter of 20-30mm), which withstand wave impact and biological adhesion corrosion;
Port machinery: the lifting arm of the shore container crane (web thickness 40-60mm), using its high toughness to resist fatigue damage caused by frequent lifting.
