A36 is a low-carbon steel that is commonly used in construction because of its combination of strength, workability and cost. A36 is hot-rolled, which makes it harder to work with and less strong than cold-rolled steel, but also less expensive.
The steel numbering system is designed to ensure uniformity in the properties of steel from multiple manufacturers. A36 is a hot-rolled steel with 0.26 percent carbon. Carbon is added to iron in the production of steel to make it stronger, but it also makes it more brittle. A low-carbon steel such as A36 is strong enough to be used in a wide range of structural applications and inexpensive enough for consumers to purchase in bulk.
A36 is hot-rolled, which means it is shaped at temperatures above the point where steel crystallizes. As a result, the steel shrinks slightly when cooling, making exact tolerances more difficult. In contrast, cold-rolled steel, such as the commonly available 1018, is subjected to further processes to give a better surface finish, but the added steps increase the cost.
A36 steel has a yield strength of 36,300 pounds per square inch. Yield strength measures how much pressure a material can take before it no longer returns to its original shape once the stress is removed. For comparison, 1018 steel has a yield strength of 53,700 pounds per square inch.