Hot - rolled round steel is produced at high temperatures, usually above the recrystallization temperature of the steel. It has a relatively rough surface finish, and the dimensional accuracy is lower compared to cold - drawn round steel. However, hot - rolled round steel is more cost - effective and suitable for applications where high precision is not required, such as general construction and large - scale structural parts. Cold - drawn round steel, on the other hand, is processed at room temperature after hot - rolling. It has a smooth surface, high dimensional accuracy, and better mechanical properties, such as higher strength and hardness, making it ideal for manufacturing precision mechanical parts.