Basics of Rolling of Steel Nov21

Basics of Rolling of Steel...

Basics of Rolling of Steel  Liquid steel is usually cast in continuous casting machines in the shape of billets, blooms, or slabs. In some plants, it is also being cast in continuous casting machines in the shape of thin slabs or dog bone sections. These shapes are processed by hot rolling by passing them through plain or grooved cylindrical rotating rolls to produce plates, sheets, rods, structural sections, and tubes etc. Rolling process is one of the most important and widely used industrial metal forming operations. It provides high production and close control of the final product. It was developed in late 1500s. It accounts for 90 % of all metals produced by metal working processes. Rolling of steel is a metal forming process in which steel is passed through a pair of rotating rolls for plastic deformation of the steel. Plastic deformation is caused by the compressive forces applied through the rotating rolls. High compressive stresses are as a result of the friction between the rolls and the steel stock surface. The steel material gets squeezed between the pair of rolls, as a result of which the thickness gets reduced and the length gets increased. Rolling is classified according to the temperature of the steel rolled. If the temperature of the steel is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the steel is below its recrystallization temperature, the process is termed as cold rolling. The rolls run on massive neck bearings mounted in housings of enormous strength and driven by powerful electric motors. These are known as mill stands. A rolling mill stand contains two or more rolls for plastic deformation of steel between rotating rolls. It basically consists of (i) rolls, (ii) bearings,...

Basics of Tribology Oct31

Basics of Tribology

Basics of Tribology Expenditure on machine condition monitoring and maintenance constitutes a significant cost in a steel plant. Tribology helps in reducing this expenditure. Tribology is a new word coined by Dr. H. Peter Jost in England in 1966. ‘The Jost Report’, provided to the British Parliament – Ministry for Education and Science, indicated ‘Potential savings of over £ 515 million per year for industry by better application of tribological principles and practices’. But tribology is not a new field. Tribology comes from the Greek word, ‘tribos’, meaning rubbing or to rub. And from the suffix, “ology” means the study of. Therefore, tribology is the study of ‘rubbing’, or ‘the study of things that rub’. Tribology is the science and technology of interacting surfaces in relative motion. It is the study (Fig 1) of (i) friction, (ii) wear, and (iii) lubrication. Fig 1 Study of tribology Tribology is the science and technology of interacting surfaces in relative motion and is commonly known as the study of friction, wear and lubrication. It is the science and technology of friction lubrication and wear and is of considerable importance in material and energy conservation. It is an old knowledge of great importance when it comes to everything in movement but as a scientific discipline tribology is rather new. Tribology, although one of the oldest engineering discipline, it is one of the least developed classical sciences to date. The reason is that tribology is neither truly a single discipline nor well represented by steady state processes. It involves all the complexities of materials. Tribology is multidisciplinary in nature, and includes mechanical engineering (especially machine elements as journal and roller bearings and gears), materials science, with research into wear resistance, surface technology with surface topography analysis and coatings, and...