CHAPTER-1
INTODUCTION
1.1 CASTING PROCESS
Definition :
Casting is one of the earliest metal shaping methods known to human beings. It generally means, pouring molten metal into a refractory mould with a cavity of the shape to be made, and allowing with it to solidify.
FIG 1.1 MOLTEN METAL POURING
1.2 History
The casting process was probably discovered around 3500 BC in Mesopotamia.
In many parts of the world during that period, copper axes and other flat object were made in open moulds made of stone or baked clay.
Casting technology was improved by the Chinese around 1500 BC.
It appears that iron casting technology in India has been in use from the times of the invasion of Alexander the Great, around 300BC.
1.3 Theory of Casting
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Usually Melting processes are done into the Furnace. In Furnace Raw material is converted into molten Metal.
1.6.5 Pouring
Pouring of Molten metal into mould with the help of Ladle. The pouring of the molten metal into the mould requires carefully control.
1.6.6 Solidification and cooling
After molten metal is poured into a mould, a series of events takes place during the solidification of the metal and its cooling to ambient temperature. The temperature of the molten metal is decrease with respect to the time.
1.6.7 Cleaning Cleaning refers to all operations necessary to the removal of sand, scale, and excess metal from the casting. The casting is separated from the mold and transported to the cleaning department. burned-on sand and scale are removed to improve the surface appearance of the casting. excess metal, in the form of fins, wires, parting line fins, and gates, is removed. Castings may be upgraded by welding or other procedures. inspection of the casting for defect and general quality is performed.
1.7Advantage of casting
1. Casting process is highly adaptable to the requirement of mass production.
2. Advantage over the forging process is
The Shang Dynasty invented and, over the years, perfected the technique of casting a bronze vessel from a clay mold assembly, which this wine vessel has also been made from using those techniques (Cantor). This mold was formed around a model of the vessel and was then cut into sections that were carved or impressed in the desired design, in this case the braided or grid design, on the inner or outer surfaces. The decorated clay piece-mold was then fired and reassembled around a clay core. Small bronze spacers were used to hold the piece-mold and the clay core apart. Then, molten bronze was poured into the mold. Using this piece-mold casting technique helped the bronze worker to achieve greater sharpness and definition in any intricate design
This new form was called hydraulic die-forming. Hydraulic stems from the Greek word hydro meaning water and aulos meaning tube (McCreight, 2004). In today’s society, hydraulic pressing and stamping of dies are used for everything from making small pots and pans to the more extravagant automobile body models. Another use that has recently developed is the more artistic use of, producing form in silver and gold. In order to achieve this smaller, cheaper scale of die-forming experiment were conducted by Richard Thomas and Ruth Girard, which eventually led to the development of the pourable epoxy steel...
Continuous casting is a casting process that is used in the manufacturing industry to produce molten steel at the temperature of 1,600OC and converted into particular size of slabs. This modern casting process is used in many steel manufactures as it has superior quality of castings, less loss of material, cost reduction and high productivity rate over the cast ingot production [1].
Iron ore is dug up from the mines and crushed and screened to the correct size fraction, where it is sent to the blast furnace. The blast furnaces uses iron ore, sinter (agglomeration of iron ore, coke and flux fines), and coke to smelt and reduce the iron oxides into liquid iron. This is done by blasting hot in the bottom of the furnace, combusting the coke and producing reducing gasses which helps reduce the iron oxides into iron. Molten iron is then cast into ladles and sent to the BOS (Basic Oxygen Steelmaking) furnace. A lance is injected into the vessel with oxygen at supersonic speeds to remove the carbon from the molten iron into form molten steel. Alloys are then added and cast into the steel stock (slabs, ingots, bar, ect...)
Bronzes are made by making two molds (one larger than the other), pouring melted bronze in...
[13] Alibaba, Hot rolled steel in the iron oxide scale broadband solutions generated, accessed on the 26th of april, http://resources.alibaba.com/topic/800012307/Hot_rolled_steel_in_the_iron_oxide_scale_broadband_solutions_generated.htm
-Developed and implemented strip casting overseas to eliminate a step in the steel making process
A mould is formed into the geometric shape of desired part. Molten metal is then poured into the mould; the mould holds this material in shape as it solidifies.
Later on, the American inventor James Watson Hendry created the first screw injection machine in 1946, with the screw injection; the machine was much more precise in terms of the speed of injection and also allowed the improvement in quality of the articles produced. The advantage that this machine also had was the fact that the materials were able to be mixed before the injection which facilitated the task. Finally, in the 1970's James Watson Hendry went onto develop the first gas-assisted injection molding process(figure 1), this new invention permitted the production of more complex commodities such as hollow items that cooled quickly. This process greatly improved f...
Bricks are constituted in mould boxes through some number of processes . Many methods can be applied but all have a common theme. A mould release medium stops the clay from sticking to the box (sand, oil or water) when soft clay is thrown into a mould,.
...of slurry to dry in between. This will then be dried and a dipping process will be repeated until a certain thickness has been achieved. The entire pattern will then be placed in an oven and the wax melted leaving a hollow cavity within the mould which matches exactly the shape of the assembly. Before casting the ‘skin’ or shells will be fired in an oven, where the heat will burn out any remaining wax and prepare the mould for the molten metal. The metal will be poured a shell through a funnel-shaped cup and flows down the Sprue channel and pass the gates into the part cavities. Once the metal cools the gates, Sprue and parts will become one solid casting. When the casting has cooled the shell will be broken off. After a few finishing operations, the castings which are exact replicas to the wax patterns are ready for shipment to the customer and for certification.
One main category of welding is arc welding. Arc welding uses a current sent from an electrode, through the base metal, and back into the ground clamp on your welder. This arc creates a tiny spot of immense heat that melts the metal around it, thus creating a weld puddle, or the puddle of molten metal. Within arc welding there are MIG, TIG, and stick welding.
Melting takes place when a solid gets enough energy to melt. When it gets enough energy it is called the melting point. An example of melting would be snow turning into water. The reverse of the melting process is called freezing. Liquid water freezes and becomes solid ice when the molecules lose a lot of energy. When a solid goes to a gas and skips the liquid, sublimation occurs. The best example of sublimation would be dry ice. Deposition is when a gas goes directly to a solid without going through the liquid phase. An example of deposition is when water vaper turns to tiny crystals.
Manufacturing is the process of convert raw materials and components to finished goods to satisfy customers’ needs or what they expect.
Through the years, the process of turning raw materials into useful materials is a tradition that hasn’t changed over hundreds of years. The general process of turning metal to blades, silicon to magic mirrors or computers and ceramics to pottery or circuits. If we examine the past we can learn much about our future because all technological advancements need is to look to our ancient ancestors and examine how they dealt with the problems of their time.