Bolt Property Class 12.9

GOST 1759.4-87 (ISO 898.1-78) establishes a classification of fasteners by strength properties. A bolt of property class 12.9 belongs to the highest class. The first number in the designation indicates the maximum tensile strength: 12×100=1200 N/mm². The number after the point is the ratio of yield strength to tensile strength.

Class 12.9 bolts belong to the category of high-strength fasteners. Their parameters are determined both by the properties of the steel used and by the manufacturing technology. Such fasteners are made by cold (or hot) heading with thread forming on special equipment, followed by application of a corrosion-protective coating.

High-strength bolt 12.9 is used for connecting heavy-duty metal structures in cases where welding is not permitted. FLOK supplies this type of fastener — check the product range on the website.