High-Strength HDG Heavy Hex Nuts (ASTM A194 2H / A563) – Precision Overtapped for Structural Joints

HDG heavy hex nuts comply with ASTM A194/A563/DIN6915, thicker and wider across flats for high torque with A325/A490 structural bolts. Galvanized blanks are CNC overtapped (+0.4–0.8mm) for smooth assembly without thread seizure. Internal bare threads get cathodic protection from HDG bolts. Heat-treated alloy steel meets Grade 2H/DH specs, no material grade counterfeiting. Widely used for pipeline flanges, steel bridges and machinery anchors, moisture-sealed cartons & pallets for sea export with full MTR certificates available.