It is mainly divided into two types: equilateral angle steel and unequal angle steel. Among them, unequal angle steel can be divided into two types: unequal sides and equal thickness and unequal sides and unequal thickness. The delivery length of angle steel is divided into two types: fixed length and double length. The selection range of fixed length for domestic angle steel has four ranges: 3~9m, 4~12m, 4~19m, and 6-19m according to the different specifications.