(1) The metallographic structure is not ideal. The main reason is that the grains are coarse and uneven. Due to the appearance of a large amount of hypereutectoid structure, the free ferrite in hypoeutectoid steel and the network carbides in hypereutectoid steel increase. In addition, the final rolling temperature is high and the cooling rate is slow, making the grains very coarse. This leads to a reduction in the mechanical properties of the wire during subsequent use and reprocessing.
(2) Uneven performance. Mainly due to the uneven coiling, the performance of the wire section and full length fluctuates greatly. Some tensile strength fluctuates up to 240MPa, and the section shrinkage fluctuates up to 12%.
(3) The metal spinning 45 iron led light shade oxide scale is too thick, and most of it is ferric oxide and ferric oxide that are difficult to remove. This is because under natural cooling conditions, the heavier the coil, the greater the thickness, and the slower the winding speed. The wire stays at high temperature for a long time, resulting in severe oxidation. The oxidation loss of naturally cooled wire rods is as high as 2% to 3%, which reduces the metal yield. In addition, the excessively thick iron oxide scale causes the wire surface to be extremely rough, which brings great difficulties to the subsequent drawing process;
(4) Since the wire rods are piled up in rolls and cooled slowly, it is easy to cause secondary decarburization for wire rods with higher carbon content.
Link to this article：The impact of uneven cooling on products after wire rod rolling
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