Manufacturing Technology - Casting.pptx

Manufacturing Technology - Casting.pptx

1. Man u f act u r i n g Technology Ca s t ing

2. C a s ti n g Content The Manufacturing Process The Foundry Industry Cast Alloys Primary Shaping Shaping of Metals by Casting Guidelines for Design Preparatory and Finishing Operations

3. The Manufacturing Process Manufacturing is the production of workpieces of a geometrically defined shape. Manufacturing technology produces products distinguished by material and geometric characteristics. According to DIN 8580 manufacturing processes can be classified into six main groups according to the criteria: changing of material cohesion Casting is an important group of the main group primary shaping

4. Classification of manufacturing processes The products of casting are so-called castings from metallic materials, so- called cast alloys. The foundry industry produces the castings.

5. The Foundry Industry The foundry industry produces castings from metallic materials . Castings in various shapes and materials are to be found in all branches of engineering : Road and rail vehicles Machinery Aerospace industry Electric power engineering Shipbuilding Pumps and fittings Electrical engineering Fine mechanics Architecture Electronics Medicine and optics Office machines and cast art Most technical products are not conceivable without castings.

6. Ad v a n t a g es of Casting Production The following outlines the economical advantages resulting from the use of castings. The advantages are the following: Exceptional freedom in the choice of shape Castability of all technically important metals Mechanical properties of cast materials that are no longer governed by those of the formed materials Optimal components through the combination of material properties and shape Near net shape castings, i. e. reduced machining costs Integral castings, i. e. reduced assembly costs Tailored castings A high recycling rate, no down-cycling Material savings through the use of castings Ecological benefits

7. Properties of Castings Castings are produced from the following material groups : iron alloys (cast steel, cast iron) aluminum magnesium titanium copper zinc tin nickel cobalt alloys All of these are cast alloys. Independent of the type of production process, in the manufacture of metallic components by casting differentiation is always to be made between the material properties and the properties of the casting itself. In order to achieve a prescribed component characteristic the material and the geometry determine and complement each other in the properties of the component. These properties depend on the following: The geometry of the part The chemical composition of the cast material The treatment of the melted material (inoculation, modification, desulfurization, deoxidation , magnesium treatment, grain refinement, etc .) The type of molding and casting process The rate of cooling from casting to the ambient temperature The subsequent heat treatment The subsequent treatment of the outer layer (chemical-thermal process, surface deformation, surface alloying, surface remelting , etc .) Changes in the surface layer through machining The type of coating (painting, galvanizing, enameling etc.)

8. Cast Alloys Cast Iron Alloys Cast iron alloys can be classified into seven groups: Gray cast iron Spheroidal graphite cast iron Ausferrite spheroidal graphite cast iron Compacted graphite cast iron Malleable cast iron Austenitic cast iron Abrasion resisting alloyed cast iron

9. Cast Alloys

10. Cast Alloys

11. Cast Alloys Cast Steel Cast steels can be classified into four groups: Cast carbon and cast low-alloy steel Cast high-alloy steel Cast stainless steel Cast heat-resisting steel

12. Cast Alloys

13. Cast Alloys

14. P r ima r y s h a ping In the processes of primary shaping, the technological manufacturing process essentially comprises the following steps : Supply or production of the raw material as an amorphous substance Preparation of a material state ready for primary shaping Filling of a primary shaping tool with the material in a state ready for primary shaping Solidification of the material in the primary shaping tool Removal of the product of primary shaping from the primary shaping tool

15. Shaping of Metals by Casting

16. Shaping of Metals by Casting

17. Shaping of Metals by Casting

18. Shaping of Metals by Casting

19. Shaping of Metals by Casting

20. Shaping of Metals by Casting

21. Shaping of Metals by Casting

22. Shaping of Metals by Casting

23. Shaping of Metals by Casting

24. Guidelines for D esign A design appropriate for manufacturing, which contributes decisively to the efficient production of a casting, can generally be achieved only by close collaboration between the design engineer and the founder. Forming by casting differs from other forming processes in that the material only receives its shape, material structure, and quality after cooling; with shrinkage – which may sometimes be considerable – in the liquid state and during solidification, and appreciable contraction in the solid state. The contraction in the solid state should be accounted for by means of a suitable allowance (allowance for contraction ). The alloying specifications often suffer considerable deviations, owing to obstruction of contraction by ribs, projections, more or less flexible cores, and mold parts.

25. Guidelines for Design

26. Guidelines for D esign

27. Guidelines for D esign

28. Preparatory and Finishing Operations Melting of Materials for Casting For transforming the metal to be cast and the additives into the molten state, a wide variety of melting equipment – e.g. shaft (cupola), crucible, and hearthtype furnaces – is available. These furnaces are heated with coke, gas, oil, or electricity. The most important types of melting equipment are : for cast iron, including malleable cast iron : cupola (shaft) furnaces induction furnaces rotary kilns (oil-fired) cast steel: electric arc furnaces induction furnaces nonferrous metal castings: induction furnaces Electrically gas-heated or oil-heated crucible furnaces.

29. Preparatory and Finishing Operations Cleaning of Castings The molds are emptied by means of emptying jiggers. The sand adhering to the casting is generally removed by means of abrasive blasting equipment employing, without exception, steel shot or steel grit made from wire. Heat Treatment Many materials only obtain the physical and technological characteristics required in use from heat treatment. This treatment requires the use of electrically heated or gas- or oil-fired furnaces in continuous or batch operation. Their size is matched to the size and quantity of the castings and their mode of operation to the wide variety of heat treatment processes.

30. Preparatory and Finishing Operations Inspection and Testing Methods Inspections of the process and the castings begin with checking of the metallic and nonmetallic feedstocks and end with the final inspection of the castings. Materials and workpieces are mainly tested by means of nondestructive testing methods such as : radiographic (EN 12681) ultrasonic (EN 12680, part 1, 2 and 3) magnetic powder (EN 1369) liquid penetrant (EN 1371 part 1 and 2) Destructive tests, e.g. tensile, notched-bar impact and bending, are usually carried out with specimens cast either separately or as an appendage to the casting; in exceptional cases, specimens taken from the casting itself may be used.