MANUFACTURING PROCESS
Steel Melting Shop
In Steel Melting Shop, an electric-arc furnace is charged with recycled steel, ferrochrome and other raw materials – nickel, molybdenum, and coke. The 130 tonne, 90 MV/A furnace melts the stainless scrap into a liquid feedstock.
Once the charge has melted and the slag removed, the melt is transferred by ladle to the argon oxygen decarburization converter. In the AOD Converter melt is decarburized and chemical composition adjusted. In the following step, in the ladle arc furnace, final chemical composition and temperature are adjusted and homogenized.
The melt is then transferred to a combination casting machine for slab or bloom, or a six-strand billet casting machine.
Wire rod mill
Stainless steel wire rod is made of billet feedstock. Billets are reheated in a two-stage reheating furnace and rolled into wire rod. Rods up to 10 mm is coiled on a laying head and larger diameters is coiled in garret coilers.
The rotary annealing furnace softens the rod to increase its ductility for further processing. Scale is removed from the hot rolled surface using salt bath and acid treatment. Samples from production stages are tested for surface defects, grain size, and tensile strength.
Bar finishing mill
Wire rod feedstock is used for producing smaller dimension bars. The cold drawing process is improving the mechanical strength and dimensional tolerances. It is achieved by cold deforming a hot rolled product using a die, resulting in a slight area reduction.
Hot rolled bars are made of billets in a hot rolling process. After cooling the bars, they are peeled to final surface condition and dimensions.
Click below to visualize the Marcegaglia Stainless Steel Long products or Marcegaglia Stainless Sheffield manufacturing process.
