AH36 steel

AH36 is a higher-tensile shipbuilding steel grade in the IACS UR W11 family, with a specified minimum yield strength of 355 MPa, against 235 MPa for normal-strength grade A. The A prefix denotes the lowest of the four toughness grades (A, D, E, F), tested by Charpy V-notch impact, with A requiring no low-temperature impact test. Higher-tensile grades let the designer reduce plate thickness for the same strength, cutting lightship weight, but the thinner plate carries a smaller corrosion margin and is more fatigue-sensitive, so its use is checked against buckling and fatigue.