1. Billet Conditioning: This process is intended for checking the surface quality of billet and removing any defects. Shot blast is used to remove any scale from the surface. Magnet particle testing and visual inspection are also used to identify any defects which must be removed using a grinder. Ultrasonic testing and dimension and geometry checking are also applied as part of the internal quality assurance process.
2. Reheating: The temperature within the furnace and the duration of reheating depend on where the product will be used. To avoid decarburization, which can affect the surface quality of the product, a billet is pre-heated sufficiently at a low temperature before being rolled within the reheating furnace. For this purpose, the fuel and air ratio are strictly controlled.
3. Rolling: The temperature, draft and speed of deformation with which the product is rolled are controlled to meet customer requirements for material features. Further measures to ensure the surface quality include the adjustment of roll roughness and gap, detection of any cracks and dimension correction.
4. Cooling: Coiling temperature at the laying head, the air flow and movement speed of the blower on the cooling bed and the cooling speed of the insulation cover are controlled to ensure that the product has the features required for each application. High carbon steel Wire rods are subject to fast cooling to achieve the microstructure required for successful drawing while low carbon steel is subject to slow cooling to ensure that the product provides the softness required for the customer to eliminate an annealing process.
5. Inspection: Samples are taken from the front and rear edges of the product after rolling and cooling for testing to identify any defects in the dimension or surface or material integrity. Packaging and tagging are also inspected according to customer requirements prior to shipping.