Rolling process

Metal Cleaning. About 204 thousand metric tons of HCl (100% basis) was consumed in 1993 for steel pickling, wherein the hydrochloric acid readily dissolves all of the various oxides present in the scale formed during the hot rolling process. Using suitable inhibitors such as alkyl pyridines, HCl reacts very slowly with the base metal rendering the surface so clean that it must be passivated with a mild alkaline rinse. 

Zinc sheet is produced by the pack-rolling process, in which 2—40 rough-roUed sheets are stacked together in packs and roUed simultaneously. Packs must be spUt frequentiy, interchanging inner and outer sheets to equalize temperatures and reductions. With care, good quaUty sheets can be produced by this technique but considerable variations in properties can occur. If a bright ductile product is desired, roUs are held at 120—150°C the reduction on the last pass is 20—40%. 

Seams. As defects, seams are distinct from weld seams and may be found in nonwelded (seamless) tubes. They are caused by crevices that have been closed by some rolling process but remain unfused. 

Seams. As a defect, a seam is distinct from the seam resulting from a welding process. Seam defects can be found in nonwelded (seamless) tubes. They can originate from blow holes or nonmetallic inclusions in the ingot and are caused by crevices that have been closed by some rolling process but remain unfused. At times, they will appear in a spiral pattern in tubes. Seams can be very tight and appear as hairlines on the surface. They can cause failure when the component is pressurized. 

No other evidence of deterioration, such as corrosion, was apparent on either surface. The cracks are probably material defects. They may be laps or seams that were present on the external surface prior to the fin-rolling operation and were exaggerated during the rolling process. 

COLD ROLLING PROCESS CAPABILITY MAP FOR ALUMINIUM ALLOYS... 

Generally, a variety of mechanical deformation processes cause the nonuniform deformation that results in the formation of residual stresses. This nonhomogeneous deformation in a material is produced by the material s parameters, largely its process parameters such as the tool geometry and frictional characteristics. For example, the rolling of a strip can be accomplished by using relatively cold squeeze rolls. In the rolling process, parameters with a small roll diameter and little reduction produce deformation penetration that is shallow and close to the surface, whereas the interior of the strip remains almost undeformed. After the removal of the deformation forces and a complete... 

The oxidative process actually starts with the onset of maceration of withered leaf. At the end of the rolling process leaf is allowed to oxidize in 5 to 8 cm beds on trays in another fermentation room. It is desirable to keep temperatures below 30°C. Oxidation at 15 to 20°C is said to improve flavor.79 High humidity prevents surface drying and consequent retardation of oxidation. 

The rolling process is used to transform cast aluminum ingot into any one of a number of intermediate or final products. Pressure exerted by the rollers as aluminum is passed between them flattens the metal and may cause work hardening. 

Powder compaction may also be achieved in roll processes, including briquetting, in which compression takes place between two rollers rotating at the same speed—that is without producing any shearing action. In pellet mills, a moist feed is forced through die holes where the resistance force is attributable to the friction between the powder and the walls of the dies. 

The only significant difficulty in processing occured at carding where static electricity caused the web to behave erratically. The static was controlled by carding the cotton with a static bar in place under the web just as it exited the crush rolls. Processing and yarn quality results for the 3 cottons made into 19.7 mg/m yarns at 13000 rpm spindle speed are shown in Table X. Spinning quality results for the Mississippi and California cottons that were made into 14.8 mg/m yarn are shown in Table XI. 

Krebs FC, Tromholt T, Jorgensen M (2010) Upscaling of polymer solar cell fabrication using full roll-to-roll processing. Nanoscale 2 873... 

---