In this article we will discuss about slab method and Ekulund's formulation for determining rolling load in hot rolling of strip. Slab Method for Determining Rolling Load: The total rolling load or rolling force PT may by be determined by integrating px over the lagging and leading zones. Thus we can write, Ekulund's Formulation for Determining Rolling Load: Ekulund gave [...]
Here we make use of slab method for analysis of rolling of wide strips. In wide strip rolling the lateral spread is very small and hence it may be assumed that the widening of strip during rolling is negligible and hence it becomes a case of plane strain deformation. The process is illustrated in Fig. 7.7. The deformation zone may [...]
The following points highlight the seven main types of longitudinal rolling stands. The types are: 1. Two High Rolling Stand 2. Three High Rolling Stand 3. Four High Rolling Stand 4. Sendzimir Rolling Stands 5. Planetary Rolling Stands 6. Universal Rolling Stands 7. Rolling of Splines. Type # 1. Two High Rolling Stand: A rolling stand is the basic rolling [...]
The names of longitudinal rolling mills are generally derived from the products they roll. Some of the names are, bloom rolling mill, billet rolling mill, merchant section rolling mill or simply merchant mill, rail and heavy section rolling mill. For getting a rolled product different types of rolling stands and several other pieces of equipment are employed. Besides, there are [...]
In this article we will discuss about the setup for hot and cold rolling of sheets and plates. Setup for Hot Rolling of Sheets and Plates: The overall view of the set up for hot rolling of sheets, strips and plates is shown in Fig. 8.19. The starting point is rolling of slabs out of cast ingot in a slab [...]
In cold rolling of steel strips and sheets, the yield strength of strip material is fairly high and very high specific roll pressures and hence rolling loads are experienced. Consequently high elastic deformations are also associated along with the plastic deformations. The elastic deformation of roll surface makes the roll surface flatter or in other words it increases the effective [...]
Variation of sheet thickness along with its width is called camber. The following three types of cambers are observed on rolled sheets. These are illustrated in Fig. 8.22. (i) Convex—Sheet is thicker in the middle and thinner towards edges. (ii) Concave—Sheet is thinner in middle and is thicker towards edges. (iii) Triangular—Sheet is thicker on one side and thinner on [...]
The process of longitudinal rolling process is illustrated in Fig. 7.1. The ingot or billet is passed through two rotating rolls mounted in a rigid frame or stand. The gap between the rolls is adjusted to less than the height of incoming billet and hence it gets rolled to a reduced height while it increases in length and width. Let [...]
The torque is obtained by integrating the frictional force multiplied by roll radius over the arc of contact (lagging and leading zones). The negative sign before the second term is due to the fact that in leading zone the metal moves faster than the rolls hence it helps to rotate the rolls. The above integration leads to rather complex calculations. [...]
The following points highlight the six main mills for reducing tube thickness and sizing. The mills are:- 1. Pilger Mill 2. Mandrel Mill 3. Plug Mill 4. Reeling Process 5. Assel Mill 6. Stretch Reducing Mill. 1. Pilger Mill: The tubular shells produced in piercing process are further processed. Pilger mill is commonly used after rotary piercing. This process consists [...]