Ceramics have also seen limited use in exhaust systems to take advantage of their insulating properties. These materials are discussed in more detail in the papers dealing with aftertreatment. Ferrous alloys are based on iron-carbon alloys and include carbon steel, alloy steels, stainless steel and cast iron. Alloying elements are added to: Interstitial holes in the FCC structure allow austenite to accommodate a greater number of carbon atoms, up to 2.
Austenite can be transformed into martensite, a very hard and brittle grain structure that is not normally used in exhaust piping systems. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. In addition to the sand, a suitable bonding agent usually clay is mixed or occurs with the sand. Whenever possible, designs are made that avoid the use of cores, due to the additional set-up time and thus greater cost.
A slight taper, known as draft, must be used on surfaces perpendicular to the parting line, in order to be able to remove the pattern from the mold. The sprue and risers must be arranged to allow a proper flow of metal and gasses within the mold in order to avoid an incomplete casting. These may be immediately visible or may only be revealed after extensive machining has been performed.
For critical applications, or where the cost of wasted effort is a factor, non-destructive testing methods may be applied before further work is performed. The name comes from the fact that wet sands are used in the molding process. Green sand is not green in color, but "green" in the sense that it is used in a wet state akin to green wood. The subsequent mold handling including turn-over, assembling, pushing-out on a conveyor were accomplished either manually or automatically.
In the late fifties hydraulically powered pistons or multipiston systems were used for the sand compaction in the flasks. This method produced much more stable and accurate molds than it was possible manually or pneumatically And Defect that Occur the process. It is not uncommon for one or more of these steps to be performed unsatisfactorily due to use of defective material or equipment, carelessness of the operator or lack of skill.
Such unsatisfactory operations result in a defective casting which may be rejected at the final stage. Since reclamation of defective castings is often costly and sometimes outright impossible, care should be taken to avoid the occurrence of the defects in the first instance.
Some of the common defects are described below. Open Blows and Blow Holes 2. Pin Hole Porosity 3. Entrapped Air and other gases 4. Cracked Casting 5. Bent or Twisted Casting 6. Dropped Mould 7. Fusion 8. Swell 9. Run out Hot tears Solidification leads to volumetric contraction which must be compensated by feeding. If this compensation is inadequate either surface shrinkage or internal shrinkage defects are produced making the casting weaker. Shrinkage faults can be reduced by providing proper gating system, pouring at correct temperature and taking care of directional solidification.
A rat tail is caused by depression of a part of the mould under compression which appears as an irregular line on the surface of the casting. A buckle is a more severe failure of the sand surface under compression. The mould must provide for proper expansion instead of forming compressed layers to avoid this defect.
Core Shift: A core shift results from improper support or location of a core. The mold usually fails because of one of two reasons: the wrong material is used or it is improperly rammed. Fairuz Will ending the presentation with explain about : 7 Explain another type manufacturing process to produce Exhaust Manifold 8 Make comparision between both type of manufacturing process, Die Casting :. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter and tin bas ed alloys.
Total views 14, Actions Shares. No notes for slide. Sand Casting 1. A tube or pipe provides a path to pour the metal in Pattern is still inside! Pouring hole In the middle of the sand is a cavity shaped like the pattern! Total views 12, On Slideshare 0. From embeds 0. Number of embeds Downloads 1, Shares 0. Comments 0. Likes You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later.
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Activate your free 60 day trial. Original Title Chapter 1 - Sand Casting. Did you find this document useful? Is this content inappropriate? Report this Document. Description: sand casting. Flag for inappropriate content. Download now. Save Save Chapter 1 - Sand Casting. Chapter 1 - Sand Casting. Original Title: Chapter 1 - Sand Casting. Related titles. Carousel Previous Carousel Next.
Jump to Page. Search inside document. TABLE Shell mold Expendable pattern Plaster mold Summary of Casting Processes Ceramic mold Intricate shapes; close tolerance parts; good surface finish. Investment Part size limited; expensive patterns, molds, and labor. Permanent mold High mold cost; limited shape and intricacy; not suitable for high-melting-point metals.
Die Centrifugal Large cylindrical parts with good quality; high production rate. Steps in Sand Casting Figure Sequence of Operations for Sand Casting Figure Ryo Haryanto.
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