Rolling of steel in Hot Strip Mill Dec03

Rolling of steel in Hot Strip Mill...

Rolling of steel in Hot Strip Mill Hot strip mills in these days are either conventional hot strip mills or strip mills for rolling thin slabs. The primary function of the conventional hot strip mill (HSM) is to reheat the semi-finished steel slabs (rolled or continuously cast) to the rolling temperatures and then to roll them thinner and longer through a series of rolling mill stands driven by large motors and finally coiling up the lengthened steel sheet for its easy handling and transport. Coils are produced with an inside diameter of 750 mm on the coilers, with  an outside diameter of up to 2400 mm and with the limitations of coil weight up to 220 kg per cm width. The hot strip mill supplies coils for cold rolling mill, strip shearing and slitting units as well as a finished product for shipment directly to the customers. Most material is transported out of the mill area by an automated coil handling system to the storage aisle. Attributes imparted to the strip by the hot rolled strip mill include surface quality, thickness, width, and flatness control as well as strip profile. Rolling of steel slabs in hot strip mill consists of several sub-processes and at the end of them the final product ‘hot rolled coil’ is produced. The main sub-processes are (i) heating of steel slabs in the reheating furnace, (ii) descaling of the heated slab and its sizing in sizing press, (iii) rolling in the roughing mill and secondary descaling, (iv) rolling in the finishing mill, (v) control cooling of the hot rolled strip and (vi) coiling of the rolled strip. Reheating of the slab Critical to the hot strip mill is the reheating furnace. Modern hot strip mills are equipped with state of...

Steel Reinforcement Bars and its Important Characteristics...

Steel Reinforcement Bars and its Important Characteristics Steel reinforcement bar is also known as rebar, reinforcing bar, reinforcing steel and reinforcement steel. It is a versatile constructional material which is widely used in the construction industry for making of the reinforced concrete. Reinforcement concrete (RC) is a composite material made up of concrete and some form of reinforcement – most commonly steel rods, bars, wires or mesh of steel rods and steel wires. The steel reinforcement bars usually consists of such shape and size that they may easily be bent and placed in the concrete so as to form a monolithic structure. The properties of thermal expansion for both steel and concrete are approximately the same. This along with excellent bendability property makes steel the best material as reinforcement in concrete structures. Another reason steel works effectively as reinforcement is that it bonds well with concrete. When passive reinforcement (steel bars) is employed, the structure is known as reinforced concrete structure. In pre-stressed concrete structure, the reinforcement (steel wire) is stressed prior to subjecting the structure to loading, which may be viewed as active reinforcement. Passive steel reinforcing bars, also known as rebars, should necessarily be strong in tension and, at the same time, be ductile enough to be shaped or bent. Steel rebar is most commonly used as a tensioning devise to reinforce concrete to help hold the concrete in a compressed state. Concrete is a material that is very strong in compression, but virtually without strength in tension. To compensate for this imbalance in a concrete slab behavior, reinforcement bar is cast into it to carry the tensile loads. The surface of the reinforcement bar may be patterned to form a better bond with the concrete. Reinforced concrete gets its strength from...