The manufacturing process of angle steel is relatively simple. Generally, large steel companies really don't produce this thing. Production technology can be divided into hot rolling and cold bending. Large-size angle steel is hot rolled, and cold bending is generally small. The standard process is to repeatedly roll the billet (such as billet) into a ∨ shape with a special section steel mill, with guaranteed material, transition arc inside the corner and reliable mechanical properties; The products produced by small workshops are directly rolled (bent) with plates or strip steel, and there is no transition arc inside the angle. Moreover, because it is curved, the internal stress at the angle is large and the mechanical properties are poor. The most important thing is that the material is not guaranteed, and it may even be "strip steel". This kind of angle steel can't be bent or welded when it is bought, and it is drilled at most.