Rolling,Rolling mills,Rolling processes &Rolling Applications by polayya chintada

Rolling,Rolling mills,Rolling processes &Rolling Applications

1. P roduction Technology: Rolling COURSE CODE: C211 REGULATION: R19 2 nd BTECH 2 nd SEM PREPARED BY : POLAYYA CHINTADA M.TECH,M.B.A,(PhD) ASSISTANT PROFESSOR LENDI INSTITUTE OF ENGINEERING AND TECHNOLOGY

2. 2 PRODUCTION TECHNOLOGY SYLLABUS UNIT 2: Metal Forming: Introduction, nature of plastic deformation, hot and cold working of metals, mechanics of metal forming; Rolling: Principle, types of rolling mill and products, roll passes, forces in rolling and power requirements; Extrusion: Basic extrusion process and its characteristics, hot extrusion and cold extrusion, wire drawing, tube drawing Nature of plastic deformation, cold and hot working process, working of a rolling mill and types, extrusion processes. COURSE OBJECTIVE: COURSE OUTCOMES: APPLICATIONS: piping and tubes, body panels, construction materials, electrical motors, doors, production of tubes and hollow pipes, frames, doors and windows Compare cold working and hot working processes. (L4) ● Explain the working of rolling mills. (L2) ● Evaluate the forces and power in rolling and extrusion processes. (L5)

3. Rolling is the process in which the metals and alloys are plastically deformed into semi finished or finished condition by passing between circular cylinders. Due to the frictional forces the metal is drawn into the opening. Metal Changes its shape due to high compressive forces. Both hot(for drastic shape changing) and cold rolling(for finishing) process are there. From the start ingot- blooms- billet- slaps which are further rolled into plat, s h Y o e u c a e N t, rod, b a r , pip e , rails. Intro of Rolling

4. Friction in rolling It depends on lubrication , work material and also on the temperature. In cold rolling the value of coefficient of friction is around 0.1 and in warm working it is around 0.2. In hot rolling it is around 0.4 In hot rolling sticking friction condition is also seen and then friction coefficient is observed up to 0.7. In sticking the hot wok surface adheres to roll and thus the central part of the strip undergoes with a severe deformation .

5. Classification of Rolling Mills Classifications based on number of rolls Two high rolling mills Three high rolling mills Four high rolling mills Cluster rolling mill Planetary rolling mill

6. Two high rolling mills(single direction) Constant direction rolling This type of mill has two rollers arranged as shown in figure below. Both the roller revolves at same speed but in opposite direction.  . The space between the rollers can be adjusted by raising or lowering the upper roll which is adjustable.  To reduce the thickness of work piece, it can be feeded from one direction only.  Least expensive https://www.youtube.com/watch?v=dpbQK7D97H4

7. Three high rolling mills This type of rolling mills consists of three rolls arranged one above other as shown in figure. The direction of rotation of upper and lower rolls are same but the middle roll rotates in the opposite direction. This type of rolling mills are used for rolling of continuous passes in a rolling sequence without reversing the drives. This results in a higher rate of production then the two-high rolling mill. https://www.youtube.com/watch?v=dpbQK7D97H4 https://www.youtube.com/watch?v=TkVfrM1FSIU

8. Four high rolling mills In this type of rolling machine, two rolls are in direct contact with the work piece and the other two rolls are used as backup rolls. The two rolls which are in direct contact with the workpieces are smaller than backup rolls and are called working rolls. Backup rolls are used to prevent the deflection of the smaller rolls, which otherwise would result in thickening of rolled plates at the centre. https://www.youtube.com/watch?v=dpbQK7D97H4

9. Cluster Rolling Mill In this type of rolling mill, each of working roll is backed up by two or more larger backup rolls. These rolls are arranged as shown in figure. This rolling mill are used in rolling hard thin materials. For rolling hard thin materials, it may be necessary to employ work rolls of very small diameter but of considerable length . In such cases adequate support of the working rolls can be obtained by using a cluster-mill. https://www.youtube.com/watch?v=13dUL9OQFvw https://www.youtube.com/watch?v=eKyUEqcDl1g

10. Planetary Rolling Mill In this type of rolling mill, a large backup roller is surrounded by many planetary working rolls. Each planetary rolls gives constant reduction. It is used to reduce large thickness of single pass of steel strip. Its rolling capacity is more than cluster rolling mill but less than rolling mill.

11. Difference between Hot & cold Rolling

12. Advantages & Disadvantages of Rolling The advantages of Rolling process are as follows. By rolling, uniform dimensions of the components can be obtained. It uses the same tool in the sense, the same rollers are responsible for the production of various components. Close tolerance is possible for the components in the rolling. high-speed production takes place in the rolling . Advantages of Rolling Process: The disadvantages of Rolling process are as follows . The cost of equipment is high. It is suitable for large scale production only. Poor surface finish and thereby we need to secondary operations like finishing etc. Disadvantages of Rolling Process:

13. Applications of rolling: Rolling is used for making hollow seamless tubes, rods etc. Large length cross sections are produced by rolling process. It is use for mass production of threaded parts like screw, bolts etc. Gears can be cut on gear blank by rolling process. Construction material, roofing panels, partition  beams , railroads, etc. are rolling product. It is used in automotive industries for manufacture various parts. Rings of turbines, bearing and other machines are rolling product. Steel sheets, plates are made by rolling process.

14. Y ours : POLAYYA CHINTADA M.TECH,M.B.A,(PhD) ASSISTANT PROFESSOR https://www.youtube.com/watch?v=3iU_Li5tG-0