Reduction of skull in the ladle

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Reduction of skull in the ladle

  1. 1. “BY PROVIDING AND INSULATION LINING” CARRIED OUT BY: K.S.V.S. APPARAO (08651A0305) A.HIMABINDU (08651A0321) M.SESHAGIRI RAO (08651A0343) K.SRIKANTH (08651A0347) M.VIKRANTH ANAND(08651AO358) CARRIED OUT AT: NAVA BHARAT VENTURES LIMITED PALONCHA,KHAMMAM(dist) ANDHRAPRADESH. GUIDED BY: G.ANAND RAO HOD”Mechanical dept”
  2. 2.  ABSTRACT  INTRODUCTION TO LADLE AND ITS DESIGN  FACTORS EFFECTING SKULL  METHOD TO REDUCE SKULL  FORMULATION USED FOR STUDY  MATLAB PROGRAM  MATLAB AND ANSYS RESULTS  CONCLUSION
  3. 3. In the era of nano and precise accuracies we have great concern of productivity, finish in all levels of manufacturing which includes casting process too. A ladle is a component used for carrying the molten metal in the casting process, this undergoes a considerable heat loss and metal gets solidified and a skull will be formed. So we surely require to make an alternative to reduce this skull to reach the required productivity and yield. The work in the project is focussed to give a theoretical and analytical information about the heat loss, problem of skull in the ladle, the mathematical formulation used for solving of the problem is presented. It also presents the results graphically and comparisons will be laid out using MAT LAB Software.
  4. 4.  LADLE: In a foundry, a ladle is a vessel used to transport and pour out molten metals. Ladles range in size from 1. small hand carried vessels that hold 20 kilograms (44 lb) 2. large steel mill ladles that hold up to 300 tones (330 tons).  Types: 1. Casting ladle: a ladle used to pour molten metal into moulds to produce the casting. 2. Transfer ladle: a ladle used to transfer a large amount of molten metal from one process to another. 3. Treatment ladle: a ladle used for a process to take place within the ladle to change some aspect of the molten metal.
  5. 5.  The ladle under consideration is composed of three layers 1. mild steel (20mm) outer layer 2. Fireclay (80mm) middle layer 3. Graphite (120mm) inner layer  The ladle is used to carry (simn) metal at a temperature of about 2100 0k  The tapping time is 20min  The carrying and pouring time is 20min
  6. 6.  The hot metal carried by the ladle is too hot and because of this heat loss occurs this results in decrease of liquid temperature ,therefore metal starts solidifying and a layer near the boundaries will be formed, this it self is the skull. Initial final Liquid alloy Graphite Brick M.S L alloy skull Graphite Brick M.S
  7. 7.  Ferro Alloys are used as inputs in the manufacture of iron and steel for removal of oxygen and imparting specific properties. These are alloys of iron and elements like manganese, silicon, chromium, etc. While manganese and silicon alloys impart strength and hardness and act as powerful deoxidizing agents, chromium alloys make steel resistant to corrosion and heat. Typical examples of end products comprise rail road rails, structural steel, automobile bodies, etc. for manganese alloys.
  8. 8.  The principal mechanisms responsible for heat loss from the molten metal are: 1. Conduction into the walls of the ladle 2. Radiation from the top exposed surface 3. Possibly convection happens naturally
  9. 9.  Consequently, a boundary separating two different phases develops and moves in the matter during the process.  Because of this the volume carried by the ladle reduces  Scrap might increase  Cleanliness of the metal will reduce  Wastage of liquid metal  Chip removal process requires
  10. 10. Figure -1
  11. 11.  An expendable lining may be applied over the interior walls of a metal handling vessel for molten metal, The expendable lining is usually applied over a relatively permanent, e.g. refractory brick, lining, Good insulator.  By pre-heating the ladle surface will considerably reduce the heat loss thus less solidification.  By providing a cap on the ladle will reduce heat through radiation.
  12. 12.  An insulation will be provided in between the layers of brick and graphite Liquid alloy skullgraphite insulation Brick M.S
  13. 13.  Heat transfer equations were laid out for all the layers and interface of skull  Finite difference formulation is chosen for solving the problem  For solving boundary conditions we have chosen explicit method  For phase change problems we have chosen fixed grid method
  14. 14.  One- dimensional transient heat conduction equation  Thermal diffusivity  Over all diffusivity equation
  15. 15.  Can be approximated with a forward finite difference formulation  Can be approximated with a central difference formulation  Combining both we get general equation to calculate temperature at required time and distance step (n,i)
  16. 16. X(t) is the position of the solid-liquid interface (moving boundary)
  17. 17. clear all; close all; clc; L=0.24; T=2400; maxk=4800; dt=T/maxk; n=48; dx=L/n; rho=6200; deltah=450000; Tm=2100; Tdash=1400; lamda=0.007; cp=483; alpha=lamda/(rho*cp); h=91.5;
  18. 18. for i=1:n+1 if i<=48 t(i,1)=333; elseif i==49 t(49,1)=953; end end for k=1:maxk+1 t(1,k)=333; t(n+1,k)=953; end for k=1:maxk for i=2:n if i<=4 r=0.38; elseif i<=20 r=0.00952; elseif i<=24 r=0.00164;
  19. 19. else r=0.0612; end t(i,k+1)=r*t(i-1,k)+(1-2*r)*t(i,k)+r*t(i+1,k); end end for k=1:maxk Tidash=t(48,k); disp(Tidash); r1=(((rho*deltah*alpha)*(Tm-2*Tdash-Tidash))/(h*(Tm-Tdash))); r2=((lamda*(Tdash-Tidash))/(h*(Tm-Tdash))); R=r1-r2; disp(R); end
  20. 20. With out insulation after tapping and before pouring respectively
  21. 21. With insulation of 20mm after tapping and before pouring
  22. 22. With insulation of 80mm after tapping and before pouring
  23. 23. Variation of skull with respect to time without insulation and with insulation
  24. 24.  Excellent insulating properties  Improved molten metal temperature control  Reduced labour cost /Lower energy cost  Safer /cleaner working environment  Improved metallurgical control  Improved Productivity  Reduced re-oxidation rate  Reduced slag carryover/fewer slag related inclusions  Improved ladle preparation productivity  Improved alloy recovery  Optimal balance between refractory life and clean ladle practice
  25. 25.  When the insulation is provided the skull reduced to considerable extent.  Comparison of the skull thickness via graphs  Ladle shell surface temperature with respect to temperatures and time for system without lining and with lining
  26. 26.  Rate of Heat Loss from Different Size Ladle with respect to temperature and weight for system Brick Lining compared with insulation lining
  27. 27.  Typical cooling profile for ladle with respect to temperature and weight remaining in the ladle for system Brick Lining compared with insulation lining

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