What crystalline structure does regular low-carbon steel have at room temperature?

At room temperature, regular low-carbon steel primarily exhibits a body-centered cubic (BCC) crystalline structure. This structure is characteristic of the ferrite phase in steel, which is stable at lower temperatures. The BCC configuration allows for the efficient packing of atoms, making it strong and providing good ductility and toughness.

In low-carbon steel, the presence of carbon in small quantities contributes to its overall mechanical properties but does not affect the basic crystallographic structure significantly at room temperature. As temperature increases, steel may transition to face-centered cubic (FCC) at higher temperatures, particularly in the austenitic phase, but at typical room temperatures, low-carbon steel retains its BCC structure.

This distinction is crucial for understanding how low-carbon steel will behave under various conditions, including how it responds to heat treatment, processing, and mechanical loading. The properties associated with the BCC structure, such as yield strength and ductility, play a significant role in the material's application in construction and manufacturing.