DIN931 Hex Bolt Part Thread | ISO4014 Marine Structural Bolt

TheDIN931 hex bolt, also known as ISO 4014, is a partially threaded hex bolt featuring a smooth unthreaded shank beneath the hexagon head. Unlike fully threaded hex head cap screws, the DIN931 design leaves a portion of the shank unthreaded, which provides superior shear strength at the grip section — a critical advantage in multi-plate structural assemblies where the bolt body must resist lateral loads without thread-induced stress concentration.

In marine and offshore environments, DIN931marine fasteners are widely specified for engine room equipment mounting, pump and compressor baseplate anchoring, generator set foundations, and hull-to-deck structural joints. The unthreaded shank bolt configuration ensures that the fastener's full cross-sectional area bears against connected plates, making it ideal for shear-critical connections found in ship propulsion systems, crane pedestals, and offshore platform modules. Marine grade hex bolts in this design are commonly supplied in grade 8.8 bolt carbon steel with HDG or Dacromet coating, or in A4-70 stainless bolt (316) for direct seawater exposure applications such as deck hardware and topside piping supports.

OurDIN931hexagon head bolts are manufactured to exacting tolerances per ISO 4014 / DIN 931 specifications, available in sizes M6 through M56 with standard metric coarse thread. Material certifications traceable to mill test reports and optional 3.1/3.2 inspection certificates per EN 10204 are provided upon request, ensuring full compliance with classification society requirements for offshore bolting and shipbuilding projects.

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