How are Steel Rods made? Steel Foundations
Rod is a hot rolled, round steel bar with diameters ranging from 0.216 to 2.25 inches (5.5 to 57 mm). It is thicker than materials designated as wire.
Rod and wire rods of smaller diameters are mainly used for further drawing into wire, while the larger diameters have various other applications, including structural reinforcement or bracing.
Rods for applications like rebar, merchant bar, rails, structural and tubes are often used in the hot rolled condition, so the properties as rolled are important for the final performance. For many other applications, the final properties are determined by subsequent processes like forging, cold drawing, and heat treatments.
Processing parameters, such as reheating temperature, hot rolling specifics of reduction per pass, temperature of each rolling pass, interpass times, strain rates in each pass, total amount of rolling reduction, steel chemistry and final cooling time-temperature profile can all influence the final rolled steel bar properties.
Hot rolling of steel rod begins by heating blooms or billets in a reheat furnace. The temperature of the billet exiting the reheat furnace is dependent on both the steel grade being rolled and the design of the rolling mill. However, it must be heated above the material’s recrystallization temperature, due to the extreme amount of reduction that occurs during this process.
The reheated steel is cleaned using a descaler and rolled to its final size through a series of rolling passes (generally referred to as roughing, intermediate and finishing passes). Then the rod is cut to the desired length and allowed to cool to ambient temperature.