ISO 4162 is the prevailing international standard for Hexagon Bolts with Flange (Small Series). These bolts feature a circular flange integrated beneath the hexagonal head, specifically designed with a "small series" head width to optimize weight and space in compact engineering assemblies.

As a core component of the ISO metric fastener system, ISO 4162 bolts provide high-clamping force while reducing surface pressure on the joined parts. Their integrated design eliminates the need for separate flat washers, making them ideal for high-vibration environments such as vehicle chassis, engine blocks, and industrial robotics where part reduction and assembly speed are critical.

The technical focus of ISO 4162 is Mass Reduction and Efficient Torque Transmission. The "Small Series" designation refers to a reduced wrench size ($s$) relative to the flange diameter ($d_c$). This allows the bolt to fit into tighter recesses compared to standard hex bolts. The flange distributes the axial load across a wide bearing surface, preventing "embedment" or damage to the substrate, which is essential when fastening aluminum or composite components.