Billets and blooms are semi-finished steel products with square section produced via continuous casting technology. Billets and blooms are produced in a wide range of steel grades and serve as basis material for the warm rolling or are processed directly into forged pieces. Generally, blooms have a section measure of 160 mm or more, and billets have smaller measures.
Slabs are semi-finished steel and are the end result of rolling ingots on a rolling mill or by processing them through a continuous casting process. Slabs will have rectangular cross sections and are used as the “starter” metals in the making of flat products such as steel plates or hot rolled coils. Slabs are always flat and rectangular and will typically range from 160 mm thicknesses and more.
Hot rolling is a mill process which involves rolling the steel at a high temperature (typically at a temperature over 1700° F), which is above the steel’s recrystallization temperature. At this temperature it can be shaped and formed easily, and the steel can be made in much larger sizes. Hot rolled steel is typically cheaper than cold rolled steel. When the steel cools off it will shrink slightly thus giving less control on the size and shape of the finished product when compared to cold rolled.
Cold rolled steel is essentially hot rolled steel that has had further processing. The steel is processed further in cold reduction mills, where the material is cooled followed by annealing and/or tempers rolling. This process will produce steel with closer dimensional tolerances and a wider range of surface finishes. All cold products provide a superior surface finish, and are superior in tolerance, concentricity, and straightness when compared to hot rolled.
Full hard steel has been cold-reduced to a point where yield and tensile strength are nearly equal. This means that the steel is hard and strong and does not deform. Elongation is <2%, typically; the last operation is either a tandem cold reduction mill or a cold reversing mill. Hardness is typically at least RB85. In the full hard condition, steel can be roll-formed, galvanized or both.
Hot-dip galvanizing is a process where steel or iron is dipped in a molten pool of zinc that maintains a temperature of around 460 °C. This molten bath begins a metallurgical bond between the zinc and the receiving metal. After the metal is pulled from the bath, it reacts to being exposed to the atmosphere, forming zinc oxide which further reacts to carbon dioxide to form zinc carbonate.
In the electrogalvanizing process, an electric current is introduced to an electrolyte solution that is applied to the steel, which reduces positively charged zinc ions to zinc metal – which is then deposited on the positively charged steel.
Galvannealed steel is a zinc-iron alloy product, where the base metal is coated by the hot-dip process, then heated to induce alloying between the molten zinc coating and the steel. The process of galvanization is performed via hot-dipping and instantaneous annealing, which produces a matte gray finish. Galvannealed steel is conducive to welding and the surface is excellent for paint adhesion.
Pre-painted steel is a bare metal substrate or corrosion resistant substrate that has had paint applied to both sides through a continuous coil coating process, which produces a uniform paint finish. The metal is unwound, cleaned and chemically treated during the process. Depending on product specifications, one or both sides may then be primed and coated, oven cured and rewound.
Quarto Plates are hot rolled plate over 12 mm thick that are not coiled during the production by hot rolling.
Cold Rolled Grain Oriented Electrical Steel (CRGO) is a special quality of steel which have a special grain surface and comes in a thickness of 0.23 mm, 0.27 mm, 0.30 mm, 0.35 mm. The lower the thickness of material the better the quality. The quality of CRGO is measured in terms of lower losses of electrical current, which flow in the core.
Cold Rolled Non-Oriented Electrical Steel (CRNGO) are silicon steels are not intentionally oriented (magnetic properties are not materially better in a given direction). Electrical Steels, from grades M-15 to M-47, are non-oriented materials. They are primarily used in applications such as motor laminations, where flux may flow in any direction with respect to the rolling direction, and where cost of producing the part is of paramount importance.
Alumized steel is a carbon steel that has been hot-dip coated on both sides with aluminum-silicon alloy. This process assures a tight metallurgical bond between the steel sheet and the aluminum coating, producing a material with a unique combination of properties possessed neither by steel nor by aluminum alone. Alumized steel shows a better behavior against corrosion and keeps the properties of the base material steel for temperature lower than 800°C.
Aluzinc, Zincalume and Galvalume are different trade names of one product. Aluzinc is cold rolled galvanized steel with metal coating composed of Aluminium , Zinc and Slicium . Aluzinc is suitable for applications where long life is an essential requirement. It is formable, weldable and readily accepts paint finishes.
Tinplate is a thin steel sheet with a coating of tin applied either by dipping in molten metal or by electrolytic deposition; almost all tinplate is now produced by the latter process. Tinplate made by this process is essentially a sandwich in which the central core is strip steel. This core is cleaned in a pickling solution and then fed through tanks containing electrolyte, where tin is deposited on both sides.
Blackplate is made of untinned iron or steel and is annealed on open flames or in an annealing box. Its dark appearance is caused by its reaction with the surrounding air. During warm rolling, blackplate can be manufactured to thicknesses of 1.5 mm or more.
Merchant bars are used by structural steel fabricators to build a number of different products. They come in flats, rounds, steel angles, squares, strips, channels – almost any form. They are generally used in structural applications that involves welding, bending, punching and forming and are commonly found in floor and roof joists, walkways and railings.
Rebar, also known as reinforcement steel and reinforcing steel, is a steel bar or mesh of steel wires used in reinforced concrete and masonry structures to strengthen and hold the concrete in tension. To improve the quality of the bond with the concrete, the surface of rebar is often patterned.
Wire rod is a rolled alloy or nonalloy steel product, produced from a semi (e.g. bloom) and having a round, rectangular or other cross-section. Particularly fine cross-sections may be achieved by subsequent cold forming (drawing). Wire rod is wound into coils and transported in this form.
These are products that are typically used in large structures such as buildings and bridges. Products in this range include Universal beams, Universal Columns, Parallel Flange Channels, Universal Joists, Rails & Equal Angles.
Stainless steel is an alloy of Iron with a minimum of 10.5% Chromium. Chromium produces a thin layer of oxide on the surface of the steel known as the 'passive layer'. This prevents any further corrosion of the surface. Increasing the amount of Chromium gives an increased resistance to corrosion. Stainless steel also contains varying amounts of Carbon, Silicon and Manganese. Other elements such as Nickel and Molybdenum may be added to impart other useful properties such as enhanced formability and increased corrosion resistance.
Seamless tubes are derived from solid steel that is in sheet or bar form and is formed into a solid round shape known as “billets” which are then heated and cast over a form such as a piercing rod to create a hollow tube or shell. These kinds of tubes are known for their ability to withstand pressure more efficiently in comparison to other methods of tube manufacturing processes, as well as being fast and cost-effective. Seamless tubes are generally used in gas lines, as well as tubes that carry liquids.
Welded tubes are produced by shaping flat steel (steel plate or steel sheet) to cylindrical shapes through mechanical pressure and then the seam is joined through welding. Quarto plates are largely used in the industry for the production of welded pipes. Moreover, hot-rolled coils are also used as a substrate for the production of welded pipes and tubes. Welded pipes are also known as ERW (Electric Resistance Welded) pipe.