WCIF/AF Presentation

1. WCIF/AF Presentation Gershwin van Harte Atlantis Foundries, 16.10.2007

2. Practical Assesment for WCIF Foundry Technology Diploma

3. Hi! I am Gershwin van Harte Started at Atlantis Foundries on the 2nd of February 2002 I am currently working in the Melting Department Why am I doing the WCIF Courses? Welcome All

4. To get a better knowledge of what I am working with and the environment and to know the product that I am producing • To produce a good product at the end of the day from the knowledge I gained from the courses • To uplift me in the workplace and strive towards gaining opportunities at Atlantis Foundries

5. WCIF Courses that I have done Introduction • Cores & Core Making • Moulding & Moulding Sands • Fettling & Fettling Techniques • Supervisory Management • Production & Planning • Melting & Metallurgy

6. Coremaking/Coreshop Cured cores Location cores

7. The cores that I made was as follow: • Step 1: The wet-sand mix is prepared by mixing sand with the two component liquid and resin binder • Generally batch mixers are used because it is more efficient and develop greater core and tensile strength • Step 2: Sand was put in corebox and tightly rammed • Step 3: Box was vented by putting a rod through the center of the corebox up to the other side • Step 4: The catalyst gas aimine entered the corebox through the ventalation hole and passes through the core causing almost instantaneous hardening of the resin coated sand • Step 5: The core was ready for ejection from the corebox after knocking it slightly with hammer • Good core compaction obviously benefits casting surface quality and also signifincantly improves core tensile strength Batchmixer Amine machine

8. Amine • There is two kinds of gas catalyst mainly DMEA and TEA • At Atlantis Foundries we are using DMEA Why DMEA? • Cure cores faster than TEA Characteristics of Amine • It has a fishy odour • Extremely flammable Precautions • Avoid skin contact • Avoid getting into eyes • High exposure causes blurred vision

9. 1 It is not dependent on any heat sources for curing 2 The process is less labour intensive,therefore cheaper 3 The process can be used for both core and mould production 4 It works well with all cast metals 5 Moulds are ejected from the box fully cured and dimensionally accurate Moulding/Cold Box Process

10. 6 The binders provide a flowable sand mix that is easily “rammed” and be used with wood, metal or plastic tooling 7 Designed for excellent castings with good shake-out properties in all metals 8 Produces sound castings with good surface finish, no gas defects and low metal penetration.

11. 9 It is permeable. If gasses doesn’t escape properly it can cause mould explosions 10 It has dry strength to prevent erosion by liquid metal during pouring 11 It possesses refractoriness to withstand the high temperature involved without melting and fusing of sand grains

12. Metallurgy/Melting Department

13. Producing liquid metal at required rate and composition At required amount of super heat, at minimum cost Types of melting furnaces Induction furnaces: Examples ABB’s & VIP at Atlantis Foundries After 250 heats it is relined Most popular for grey cast iron Pressure pour furnace: This is were all castings are cast as per specification e.g. pouring temperature, pouring time and slag free Every year it is relined What is the process of metal melting?

14. What is the process of metal melting? • We at Atlantis Foundries are making use of induction furnaces • Advantages: • Precise controlled composition of base liquid metal • Can use a wide range of charge materials • Environmental Friendly • Higher melting rate because of stirring effect

15. What is the process of metal melting? Channel furnace/holding furnace • There are 3 furnaces at Atlantis Foundries that holds 50 tons of Molten metal eachThis is not a Melting furnace but a storage place for liquid metal • Precise control of temperaturesEvery second year it is relined

16. Factors that will cause a lining to fail • Thermal design • Mechanical design • Chemical damage • Material selection • Anchoring failure • Installation • Commissioning

17. Raw materials Types Returns Steel scrap

18. Raw materials Coils Snippers

19. Ferro Alloys Fe Cr Fe S Fe Mn Fe Si Carburiser/Carbon

20. Typical Furnace charge as per work instruction at Atlantis Foundries • Returns 2000 kg • Scrap blocks 2000 kg • Steel scrap 1000 kg • Snippers 1500 kg • Bails 1500 kg • Coils 1000 kg • Pig iron 1000 kg Total = 10 000 tons

21. The Casting After knock out After shot blast

22. Wedge chill test Temperature: 1460 degrees Pouring time: plus + 5 sec Chemical composition Melt Quality Control Test that was done • Spectrometer machine

23. The results of the spark analysis of that day was as follow:

24. Design of gating system/runner system Ingate • The idea was that the metal must run down to the end of the runner bar, all the inclusions in the metal and sand from the runner system are trapped within the runner bar Runner bar Runner system before cutting

25. Inoculation Of Grey Cast Iron Name the effects of inoculation of graphite flake iron? • Reduce chill and promote graphite • To reduce fine graphite and associate it ferrite • To promote uniform structures • To obtain a small increase in strength There are two main ways of inoculation? • Ladle inoculation • Late inoculation There are 3 ways of late-inoculation • Instream inoculation • Wire feed inoculation • In mould inoculation What is the nucleation of iron? • It increase the number of points available providing site for the growth of graphite

26. Why must cast iron have enough inoculation? • The possibility of white iron forming in the fast cooling parts of grey iron castings is high and it will have negative effects of including Iron Carbide • Iron Carbide is very hard and brittle and machining is extremely difficult Very good inoculation Small chilled area Poor inoculation Large chill area

27. Main constituents in cast iron Cementite Pearlite Ferrite Phosphide- eutectic Factors that influence the properties of the structure of grey cast iron Size Amount Contribution of graphite flakes Composition Cooling Degree of nucleation of the iron Basic elements for the composition of cast iron Carbon Silicon Phosphorus Manganese Sulphur Micro StructureIn Atlantis Foundries the casting will be 97% Pearlite, 3% Ferrite & traces of Cementite

28. Characteristics Of Elements Ferrite • Single phase solid solution • It is very soft • Low strength • Low wear resistance • Hardness (100 Brinell to 150 Brinell) • Good machine ability Under which circumstances will ferrite occur/forms? • Slow rates of cooling • High silicon contents • High carbon equivalent Pearlite • High wear resistance • Very good tensile • Good machine ability Cementite • Very hard • High wear resistance • Extremely poor machine ability and brittle

29. Quality/Defects Scabbing defects can be caused by: • High pouring temperatures • Long pouring times Blows • High pouring temperatures • Long pouring times • Not drilling vent holes at the mould line • Turbulence while pouring metal • Increase resin for Coremaking Slag • Ladles not being slagged off properly, not using slag bond • Pouring basin not being kept clean from slag build up • Mould line not using correct filters to stop slag going into casting

30. Slag • Slag is formed in an electric melting furnace • It is formed from sand, dirt or rust on the raw materials • Slag floats on the surface of metal and must be removed before tapping/transferring to pressure pour furnace • Slagging off is a very unpleasant job for a Furnace Operator • It is advisable to use less dirt, sand and rust-free charge materials • Many slags are liquid and difficult to collect • It is adviceable to use SLAX-SLAGBOND • Slax granules expands at metal temperature and it mops up slag that is on the metal and can be lifted up with ease from the metal

31. Dangerous contaminations in metal that can cause defects • Lead It can cause losing your tensile strength on casting • Boron It causes cracking and chill in casting • Aluminum May cause Pinholing defects in casting • Nitrogen It can cause blowholes, heavy sections in castings are mostly affected Titanium neutralise the effect of nitrogen

32. END