Bubbles – various sizes and forms of swelling on the surface of the sheet. They are formed from the bubbles that have not been brewed during hot rolling, as well as as a result of hydrogen diffusion released during the interaction of sulfur or hydrochloric acid with metal when etching. If your production requires a high -quality trailer, you can choose it here: I will buy a trailer. Stratification is found at the place of cutting or on the side edges. The reason for its occurrence is the presence of non -metallic inclusions that fall into metal from refractor when the metal is released in the bucket and spilled into a mackerel. Longitudinal and transverse cracks, as a rule, are the result of uneven or fast heating and overheating of the metal before hot rolling, uneven extract of the metal, improper tuning and profiling rolls of cold rolling, as well as unsatisfactory cutting out external defects on the ingot, slab and tackle. The reason for the formation of cracks can also be the reduced plasticity of the metal, which in some cases is a consequence of the gas -saturation or pollution of steel by non -metallic inclusions, as well as overheating of the rolling of steels characterized by a narrow temperature interval of plasticity. Shells – local recesses on the surface of the sheet, formed as a result of opening small voids or pressing the ward to the metal that has been to the rolls of the correct machine. The sinks from the scale are formed as a result. After etching in its place there are traces. Halosovins – small cracks on the surface of metal of various lengths and depths stretched along the rolling, appearing as a result of opening and stretching during the rolling of subcortical bubbles and non -metallic inclusions.