Rolling Definition: The first process that is used to convert material into a finished wrought product. Thick starting stock rolled into blooms billet or slabs

Types of Rolling flat rolling: The final shape of the product is either classed as sheet or plate . Profile rolling: The final product may be a round rod or other shaped bar, such as a structural section (beam, channel, joist etc)

Profile Rolling Definition: Rolling is defined as the reduction of the cross-sectional area of the metal stock, or the general shaping of the metal products, through the use of the rotating rolls.

Classification of Rolling Hot rolling. Cold rolling.

Hot rolling Definition Hot rolling is a plastic deformation process, in which mechanically shapes are fromed of the meterial at a temperature above its recrystallisation temperature.

Benefits of hot rolling  Flow stresses are low, hence forces and power requirements are relatively low, and even very large work pieces can be deformed with equipment of reasonable size. Ductility is high; hence large deformations can be taken (in excess of 99% reduction). Complex part shapes can be generated.

Disadvantages of hot rolling. The hardness is generally lower. most metal will experience some surface oxidation resulting in material loss and poor final surface finish. Low producation rate.

Cold rolling. Definition. When the rolling processing temperature of the mechanical deformation of metal is below the recrystallization temperature, the process is termed as cold rolling.

Advantages of cold rolling In the absence of oxidation, tighter tolerances and better surface finish obtained. Thinner walls are possible. The final properties of the workpiece controlled cold rolling can be retained Wastage is about 6%. High production rate.

Disadvantages of clod rolling It has high initial cost. Low production rate. High power consumption. High wear and tear of the rollers.

Flat Rolling Definition: The final shape of the product is either classed as sheet or plate .

Rolling Mills Definition: A rolling mill is a machine or factory used to shape and process metal by passing it between a pair of working rolls. The metal is passed between two tough cylinders numerous times, with the distance between the cylinders being decreased with each pass so the metal becomes thinner and thinner.

Type of rolling mills. Cold rolling mills: Cold rolling is a metalworking process in which metal is deformed by passing it through rollers at a temperature below its recrystallization temperature. Cold rolling increases the yield strength and hardness of a metal by introducing defects into the metal's crystal structure. Hot rolling mills: Hot rolling is a hot working metalworking process where large pieces of metal, such as slabs or billets, are heated above their recrystallization temperature and then deformed between rollers to form thinner cross sections.

Classification of rolling mills Mills classified in accordance with the name of the product which they roll, follow: Blooming, cogging and slabbing mills, being the preparatory mills to rolling finished rails, shapes or plates, respectively. If reversing, they are from 34 to 48 inches in diameter, and if three-high, from 28 to 42 inches in diameter. Billet mills, three-high, rolls from 24 to 32 inches in diameter, used for the further reduction of blooms down to 1J^ x IJ^-inch billets, being the preparatory mills for the bar and rod Beam mills, three-high, rolls from 28 to 36 inches in diameter, for the production of heavy beams and channels 12 inches and over.

Rail mills with rolls from 26 to 40 inches in diameter. Shape mills with rolls from 20 to 26 inches in diameter, for smaller sizes of beams and channels and other structural shapes. Merchant bar mills with rolls from 16 to 20 inches in diameter. Small merchant bar mills with finishing rolls from 8 to 16 inches in diameter, generally arranged with a larger size roughing stand. Rod and wire mills with finishing rolls from 8 to 12 inches in diameter, always arranged with larger size roughing stands. Hoop and cotton tie mills, similar to small merchant bar mills11. Armour plate mills with rolls from 44 to 50 inches in diameter and 140 to 180-inch body. Plate mills with rolls from 28 to 44 inches in diameter13. Sheet mills with rolls from 20 to 32 inches in diameter. Universal mills for the production of square-edged or so-called universal plates and various wide flanged shapes by a system of vertical and horizontal rolls Tube mills for the production of tubes. Special mills, such as slitting, piercing, tire wheel mills, etc. Cold mills.

Finished product of rolling mills First Group Bars, rods, wire rods, bands and hoops are produced from blooms, slabs and billets by reducing this material to the simplest forms, such as squares, rounds and flats. Second Group Shapes are reduced from blooms, slabs or billets to forms having more or less irregular section, the original material is not only reduced but it is also developed into a definite shape. Third Group Plates and skelp is the material obtained by rolling slabs and blooms in mills known as plate and skelp mills. A sheet is the product obtained by rolling sheet bars in sheet mills.

Shape Rolling Definition: shape rolling is a metalworking forming process in which structural shapes are passed through rollers to bend or deform the work piece to a desired shape, while maintaining a constant cross-section.

Examples of shape rolling I-beams, H-beams, T-beams, Z-beams, angle iron, channels, pipes and tubing, bar stock, and railroad rails

Process of shape rolling shape rolling uses profile rolling techniques where the work piece is passed through a series of rollers (of larger magnitude than that of common rolling devices) that match the required geometry, the most common method being the use of 3 rollers. When the distance between the rollers is adjusted, various curvatures can be made.

Seamless Tubes Definition: In this process Seamless (SMLS) pipe manufacture. is formed by drawing a solid billet over a piercing rod to create the hollow shell.

Production Seamless piping and tubing The billet is heated to between 1200 and 1300°C and then positioned between two eccentric rolls arranged at an 6 degree angle to each other and operating in the same direction, thus locking the billet into a kind of gear mechanism. As the billet progresses lengthwise through the rolls in a helical motion, it is pierced by a plug which is supported at the run-out end of the piercing mill by a freely rotating bar. In other words, the plug is "drilling” the hole into the billet as it passes through it.

Tube Definition: The pipe which has seam or welded joint in it. The weld flash can be removed from the outside or inside surfaces using a scarfing blade. The weld zone can also be heat treated, so the seam is less visible.

Production of seam tubes The process involves the progressive bending of metal strip as it passes through a series of rollers at speed up to 80m/sec. Only bending take place, all bends are parallel. Seam welding process carried out to form a proper tube.and wed flashes are removed by scarfing blades.

Compression of seamless pipes &seam tubes Seamless pipe provides the most reliable pressure retaining characteristics. easily available than welded pipe. More Expensive. Size is less than 3 inch dia. Seam tube: Welded pipe often has tighter dimensional tolerances. cheaper if manufactured in the same quantities. Size is greater than 3 inch dia.