YS (yield strength) marking

Yield-strength (YS) marking is the plate-identification practice of stamping and painting each steel plate with its grade, which encodes the yield level, so it can be traced from the mill through the cutting line into the hull. Under IACS UR W7 and W11 each certified plate carries a hard-stamped heat and plate number, the grade mark (for example AH36, DH36, the number giving the yield in tens of MPa), the classification-society brand, and often a color code, plus matching marks on the mill certificate. Yards rely on the marking to sort plate by grade and transfer the identification onto cut parts before the original mark is lost. It is the audit trail behind material traceability at survey.