AH40 ship plate is the top model among high-strength hull steels. "40" represents the minimum yield strength of 400MPa. It is specially developed for high-end ships and deep-sea equipment in extreme environments. Its material adopts the "ultra-pure steel + precision micro-alloying" process: vacuum decarburization makes the carbon content ≤0.14%, calcium treatment is used to control the inclusion morphology (rating ≤1.5 level), and niobium (0.03%-0.06%), vanadium (0.05%-0.10%), and titanium (0.02%-0.04%) are accurately proportioned to form nano-scale carbonitrides (size <100nm), achieving a perfect balance of "strength-toughness-weldability".
Features reach the top level in the industry:
Ultimate strength: yield strength 400-540MPa, tensile strength 570-720MPa, elongation after fracture ≥21%, can withstand deep-sea loads equivalent to the water pressure of 40 floors;
Toughness in extreme environments: -40℃ impact absorption energy ≥47J, still maintains ductile fracture characteristics in the Arctic route (minimum -50℃), avoiding brittle failure;
Z-axis crack resistance: AH40-Z35 model thickness direction shrinkage ≥35%, through ultrasonic flaw detection (UT) A-level standard, suitable for key load-bearing parts with thickness >50mm;
Welding innovation: When using high heat input welding (wire energy ≤50kJ/cm), the HAZ (heat affected zone) impact energy is still ≥34J, which can greatly improve the efficiency of thick plate welding.
The advantages are reflected in three "high" dimensions:
1. High-performance barriers: Currently, only a few steel mills in the world have stable production capacity. The smelting process requires the oxygen content of molten steel to be controlled to ≤15ppm and the hydrogen content to be ≤2ppm, and the technical threshold is extremely high;
2. High value-added applications: Mainly used for high-end projects such as luxury cruise ships and deep-sea drilling platforms with a unit price of more than 100 million US dollars. The price per ton of steel is 3,000-5,000 yuan higher than AH32;
3. High reliability guarantee: Through DNV GL's "smart material" certification, it supports digital life cycle management and can monitor the fatigue damage of steel plates in real time.
Uses focus on cutting-edge fields:
Core structure of luxury cruise ships: keel (thickness 80-120mm), double bottom strong frame (60-100mm), bearing the weight of tens of thousands of passengers and complex wave loads;
Deep-sea engineering equipment:
Column structure of semi-submersible drilling platform (diameter 5-8 meters, thickness 100-150mm), resisting 12-level typhoon and 30-meter waves;
Pressure shell (thickness 50-80mm) of deep-sea mining vehicle, withstanding ultra-high pressure (40MPa) environment of 4000 meters deep sea;
Special military ships: ammunition compartment armor plate (thickness 30-50mm) of military supply ship, with impact and explosion resistance;
Polar research ship: using AH40 + stainless steel composite plate technology, the bow icebreaker blade (thickness 150mm) can break 1.5 meters thick ice, while the inner stainless steel resists fresh water corrosion.
