The connecting rod of the drill bit is primarily made of high-strength alloy steel to maintain stability and wear resistance while withstanding significant torque and impact. Common main materials include 45# steel, 40Cr alloy steel, and some heat-treated tool steels. These materials possess good overall mechanical properties, being both durable and rigid.
The connecting rod may also utilize chromium-molybdenum steel or steel that has undergone carburizing and heat treatment processes to further enhance surface hardness and fatigue resistance. This reduces wear caused by prolonged high-speed rotation, extends service life, and lowers the risk of loosening or deformation at the connection point.
Some connecting rods undergo chrome plating or blackening treatment to improve rust and corrosion resistance, which is especially important in humid or metalworking environments. The clamping parts of the connecting rod (such as hexagonal or round shank structures) are typically precision-machined to ensure a tighter fit with the drill chuck and reduce slippage.
The material selection for the hole opener connecting rod follows a principle: it should balance core strength and toughness, while also possessing good wear resistance and fatigue resistance to ensure safety and reliability under high torque conditions.
