The most common type of metal used in manufacturing industrial drums is steel and it is rare that a different metal would be used.
The three main types of steel used to fabricate drums are carbon steel, stainless steel and cold rolled steel. Carbon steel is steel that has carbon as the primary alloying constituent, and the properties of the metal are determined by how much carbon it contains. Although carbon steel is generally fairly corrosion resistant, stainless steel is more so due to the addition of a minimum amount of chromium, typically 10.5 – 11%. Cold rolled steel is steel that has undergone a cold hardening process in which the steel is rolled at room temperature in order to preserve its original crystalline structure.
Each of these different types of steel are better suited for certain industries and applications: for instance, carbon steel is often used in the handling of hazardous chemicals for chemical processing, pharmaceutical, petrochemical and wastewater industries; stainless steel is ideal for sanitary applications as well as applications requiring a high degree of corrosion resistance such as food and beverage, industrial manufacturing and construction; and cold rolled steel is best-suited for industries requiring very high tensile strength, such as mining and defense.
Metal drums are manufactured using roll forming processes. A continuous metal forming process, during roll forming a metal sheet is rolled into the shape of a ring. This rolling is brought about by roll forming machines that consist of sequences of calenders, or roller die pairs, that are positioned both above and below the metal sheet. As the sheet moves through the machine, the rollers bend the material along the linear axis.
Most commonly, roll formed parts are created at room temperature, causing it to be a cold forming process. After the metal sheet is in ring-form, the ends of the ring are welded together to create the body of the drum. Steel rings are welded onto the body at the bottom of the drum, a quarter of the way up from the bottom, a quarter of the way from the top and at the top of the drum to serve as reinforcement.
The next step of construction depends on whether the drum is to be open or closed head. Open head drums feature removable heads, while closed head drums, also called tight head drums, have a permanent lid with a small opening to allow for the enclosed material to be poured out. For industrial applications, metal drums are often required to meet both United Nations (UN) and Department of Transportation (DOT) regulations, which have fairly strenuous restrictions and requirements concerning the steel drum manufacturing process.