DESIGN AND ANALYSIS OF AXIAL CROSSING OF WORK ROLLS IN ROLLING MILL WORK ROLL ASSEMBLY: A REVIEW

Transcription

1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 7, Issue 2, March-April 2016, pp , Article ID: IJMET_07_02_021 Available online at Journal Impact Factor (2016): (Calculated by GISI) ISSN Print: and ISSN Online: IAEME Publication DESIGN AND ANALYSIS OF AXIAL CROSSING OF WORK ROLLS IN ROLLING MILL WORK ROLL ASSEMBLY: A REVIEW Nilam K. Wankhade PG Scholar, Department of Mechanical Engineering, Datta Meghe Institute of Engineering Technology and Research Wardha, India Dhananjay. R. Ikhar HOD, Department of Mechanical Engineering, Datta Meghe Institute of Engineering Technology and Research, Wardha, India ABSTRACT Rolling Mill is one of the machine for rolling steel or other metal into sheets. For reliable and efficient working of rolling mill it is necessary that all the components used in rolling mill should work properly without fail. Work roll assembly is very important part of the rolling mill. It has been observed that In hot rolling mill during the metal rolling at finishing mill (4-Hi mill Reversible), work roll pair come out due to the axial crossing of work rolls and due to which uneven thickness of metal, strip breakage, bending of locking plate, metal shifting and equipment breakdown occurs. After the Study it has been observed that wear of the work roll liner is one of the reasons for the axial crossing of the work rolls. By modeling in Pro-E software and analysis in ANSYS13.0 (workbench) software it has observed that the wear is there in the liner. Through this analysis I found the stresses developed on liner under working process. Axial crossing of work rolls is the major Problem Facing by Steel rolling companies and due to this crossing there will be defects in the Products of the rolling mill. By conducting the detailed analysis it has been found that if we change the material 1045 steel to improved material or induction hardening of the liner then there will be less wear in the liner so that we can reduce this problem. Key words: HRM (Hot rolling mill), Work Roll Axial Crossing, work roll liner, analysis etc. Cite this Article Nilam K. Wankhade and Dhananjay. R. Ikhar, Design and Analysis of Axial Crossing of Work Rolls in Rolling Mill Work Roll Assembly: A Review. International Journal of Mechanical Engineering and Technology, 7(2), 2016, pp editor@iaeme.com

2 Nilam K. Wankhade and Dhananjay. R. Ikhar 1. INTRODUCTION Rolling is classified according to the temperature of the metal being rolled. If the temperature of the metal is above its re-crystallization temperature, then the process is known as Hot Rolling. If the Temperature of the metal is below its re-crystallization temperature the process is known as Cold Rolling process. In Hot rolling process slabs are heated in a reheating furnace before being processed. The heated slabs from the furnace are rolled to attain its desired dimension through different steps. In the first step it rolled through roughing mill stand and finished in finishing mill in second step. Work roll assembly is the main part of the HRM as the actual reduction is done in this assembly. Figure 1 Rolling mill work rolls Assembly The problem is related to HRM Finishing Stand. In hot rolling mill during the metal rolling at finishing mill (4-Hi mill Reversible), work roll pair come out due to the axial crossing of work rolls and due to which uneven thickness of metal, strip breakage, bending of locking plate, metal shifting and equipment breakdown occurs. After the Study it had been observed that wear of the work roll liner is one of the reasons for the axial crossing of the work rolls. The aim of review is to find out what are various causes of defects occurred in the product. Various papers has been referred for collecting the data for Finding the causes of failure and finally how those failure can be avoided by using various tools have been identified. 2. FUNCTIONS OF WORK LINER Liners plays very important role in maintaining position of roll assembly for achieving the desired quality of product being rolled. For a mill to roll any product to an accurate shape and size, the alignment of the rolls and the roll gap must be precisely maintained. Wear on the mating surfaces of the roll chocks liner and mill housings liner can cause excessive clearance between the two parts which can cause axis crossing of roll, resulting Loss of gauge control, Loss of shape, reduced speed, and ultimately result in loss of production editor@iaeme.com

3 Design and Analysis of Axial Crossing of Work Rolls in Rolling Mill Work Roll Assembly: A Review Figure 2 Rolling Mill Work Liner 3. LITERATURE REVIEW Sudipta Sikda (R & D, Tata Steel, India) etal, [1] discussed that predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka s equation has been used to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been found to have a positive effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described. Dr. Karl Heinrich Schroder [2] conducted a study regarding what should be the conditions to improve the performance of work roll. They have discussed the important parameter related to rolling. Rolling condition can be determined in a good informative way from rolling schedules, rather than from the mills layout. The rolling conditions should be studied for all rolling schedules of a rolling program to detect possible critical conditions. Diego Alvarez, etal [3] discussed the problem of uneven thickness of slab. The deviation of the thickness causes stops in the rolling train, due to the clogging of the strips in the finishing mill. For this defects they have suggest the fuzzy controller to receive the input signal and give the output. With the fuzzy control can get the signals that something is wrong and so that we take the corrective action to reduce the defects. Tapany Udomphol, [4] derived the expression related to rolling and formulae of the each and every parameter such as pressure, force, angle of bite etc. These are very important formulas in any project related to rolling mill or rolling process. If the diameter of roll increases then the length of contact will also increase and we will get the maximum thickness of the slab in single pass of rolling. Kumar K. Mukerjee, [5] explained the basic concept of rolling and theories of strip rolling. Author also explains practical application of the rolling theories and how editor@iaeme.com

4 Nilam K. Wankhade and Dhananjay. R. Ikhar this concept used in designing of hot strip mills. Design of the rolling mill should be accurate and proper so that we can get the good strip thickness and product without any defects. A. K. Ray, et al, [6] discussed that what are the causes for the failure of work rolls in cold rolling mill. They collected the samples from steel plant were examined for their chemistry, inclusion content, microstructures, carbide characteristics, hardness and the retained austenite content. The residual stresses are measured on the inner as well as the outer surface of the spalled roll pieces. The results obtained have been discussed in the paper. 4. DISCUSSION From the literature survey, it is revealed that proper designing of the mills is very important for the quality of the rolled product. At the time of designing mills consideration of the parameters is very important. With the help of these papers manual calculation for the forces acting on the liner can be done. Analysis using ANSYS software to find out Stresses and the wear in the liner of work liner of the rolling mill work roll assembly may be carried out for further study. 5. CONCLUSION Model based on the FE method can be used to find out the stresses and deformation of the liner in which the wear takes place. Effects of main rolling process parameters such as rolling speed, Pressure, Roll diameter and strip reduction (Thickness) has to be taken into consideration at the time of Force calculation. Basic concept and theories of strip rolling plays very important role in any work associated to rolling. So it has been decided by referring various data from the Papers that manual design, followed by modeling on the software via cad tools CREO and analysis on ANSYS13.0 (workbench) of the liner will be done. The aim of the project is to reduce the problem of the axial crossing of the work rolls in rolling mill assembly; by keeping this in mind project work have been started. REFERENCES [1] Sudipta Sikda (R & D, Tata Steel, India), Shylu John (R & D, Tata Steel, India), Ashwin Pandit (R & D, Tata Steel, India) Raju Dasu (R & D, Tata Steel, India) Analysis of roll stack deflection in a hot strip mill Paper accepted March, Technical Editor: Anselmo E. Diniz. 284 / Vol. XXIX, No. 3, July-September 2007 [2] Dr. Karl Heinrich, Rolling conditions in hot strip mills and their influence on the performance on the work Rolls Institute Latinoamericano del Fierrov Acero, Maxico, March , MPT Plant and Technology Issue No. 4/88, Pages 44-56, Verlsg Stahleisen MbH, Dusseldorf. [3] Diego Alvarez, Alberto B. Diez, Faustino Obeso, Slab curvature compensation in hot rolling mill by means o Fuzzy Control, Paper at the III seminar on rolling Mill Rolls, Institute Latinoamericano del Fierro v Acero, Maxico, March [4] Tapany Udomphol, Rolling of metals Suranaree University of Technology Jan- Mar [5] Kumar K. Mukerjee A critical review of the mechanics of metal rolling, its application to the design of hot strip mills, Sir George Williams University Montreal Canada, April editor@iaeme.com

5 Design and Analysis of Axial Crossing of Work Rolls in Rolling Mill Work Roll Assembly: A Review [6] A. K. Ray, K. K. Mishra & P. N. Chaudhary Failure analysis of rolls of cold rolling mill in steel plant Proceedings : Cofa-1997 Nml Jamshedpur ; pp [7] R. Chandramouli Analysis of strip rolling by Associate Dean-Research SASTRA University, Thanjavur [8] Saral Dutta Hot rolling practice, B. Tech. (Hons.), I.I.T. Executive Director, ISP & RMD, SAIL. [9] Saral Dutta B. Tech. (Hons.), I.I.T. Executive Director, ISP & RMD, SAIL (Retired), Flat and shape rolling processes. [10] Dr Ravi Kumar Goyal Anurag Joshi and Umesh Gurnani, Comparison of Roll Deformation In 4hi Rolling Mill and 20 Hi Rolling Mill Due To Thermal Stresses, Overloading, Spalling and Design Parameters. International Journal of Design and Engineering and Technology, 7(1), 2016, pp [11] A text book of Machine Design by Khurmi and Gupta editor@iaeme.com