Fasteners, formed in cold condition, without involving the use of any heating process for head or body formation(except for heat treatment), are termed as cold forged fasteners. Also better known as cold headed fasteners. Common products include hex bolts, allen head bolts, hex nuts and all major screw types. Cold forged technique if useful for mass production of fasteners which includes sizes from M1 to M24 or #0 to 1". Cold headed fasteners are produced from wire rod in a form of coil, feeded to cold forming machine, which then processed through a series of operations to form the end product. Cold forged bolts, screws and nuts are much more cheaper than hot forged, given the condition, they are mass produced.
High quality fasteners are mass produced in carbon steel, high tensile alloy steel and stainless steel using cold forged technique. A193 B7, B8, B8M, A194 2H, 4, 7, F568, F593, F594, F738M, J429, BS EN ISO 3506-1, 3506-2 are some frequently used specification for cold forged fasteners.
Wire rod is the statutory need for producing cold forged fasteners in quantities. Wire rod of suitable dimensions and weight is fed to the cold forming machine. The feed then passes through a series of operations including head formation, body machining, stamp marking & threading.Depeding upon the requirement, the end product may undergo surface treatment for aesthetic appearance.
Cold forged fasteners are produced between M1 to M24 in metric and #0 to 1" in imperial/inch.
Below standard refers to material specification for cold forged fasteners.