Difference Between Casting and Forging Processes
Casting is the process in which metal is heated until it melts. While it is in the molten or liquid state, it is poured into a mold or container to create the desired shape.
Forging is the application of thermal and mechanical energy to steel billets or ingots to cause the material to change shape while in a solid state.
Difference Between Casting and ForgingDifference Between Casting and Forging
Metal Casting Process
Differences
Metal Forming Process
Casting is a manufacturing process where a
the solid is melted, heated to the appropriate temperature (sometimes treated to modify its chemical composition), and then poured into a cavity or mold, which contains it in the appropriate form during solidification. Thus, in a single step, simple or complex shapes can be made from any metal that can be cast.
The resulting product can have virtually any configuration the designer
wishes.
the solid is melted, heated to the appropriate temperature (sometimes treated to modify its chemical composition), and then poured into a cavity or mold, which contains it in the appropriate form during solidification. Thus, in a single step, simple or complex shapes can be made from any metal that can be cast.
The resulting product can have virtually any configuration the designer
wishes.
Working principle
The plastic deformation of a metal to produce a useful shape. Metal forming is done at high levels
or hot working temperatures with processes such as forging, or it is done at ambient cold working temperatures with processes such as stamping or bending.
or hot working temperatures with processes such as forging, or it is done at ambient cold working temperatures with processes such as stamping or bending.
GETTING THE CASTING GEOMETRY-
The traditional method of obtaining casting geometry is by sending blueprints to the foundry. This is usually done during the quote request process.
However, more and more customers and foundries are exchanging part geometries through the exchange of computer-aided design files.
However, more and more customers and foundries are exchanging part geometries through the exchange of computer-aided design files.
PATTERN MARKING-
The pattern is a physical model of the casting used to make the mold.
The mold is made by packing some easily formed aggregate material, such as molding sand, around the pattern. When the default is
removed, its impression provides the mold cavity, which is finally filled with metal to become the casting.
removed, its impression provides the mold cavity, which is finally filled with metal to become the casting.
If the casting is hollow, as in the case of pipe fittings,
Additional patterns, called cores, are used to form these cavities.
Additional patterns, called cores, are used to form these cavities.
COREMAKING-
Cores are shapes, usually made of sand, that are placed in a mold cavity to form the inner surfaces of castings. Thus, the empty space between the core and the surface of the mold cavity is what eventually becomes the casting.
MOLDING-
Molding consists of all the operations necessary to prepare a mold to receive molten metal. Molding usually involves placing a frame
aggregate around a pattern held by a supporting frame, withdrawing the pattern to exit the mold cavity, fixing the cores in the mold cavity, and finishing and closing the mold.
aggregate around a pattern held by a supporting frame, withdrawing the pattern to exit the mold cavity, fixing the cores in the mold cavity, and finishing and closing the mold.
MELT AND POUR-
The preparation of molten metal for casting is referred to
just like melting. Melting is usually done in a specifically designated area of the foundry, and the molten metal is transferred to the casting area where
the molds are filled.
just like melting. Melting is usually done in a specifically designated area of the foundry, and the molten metal is transferred to the casting area where
the molds are filled.
CLEANING-
Cleaning refers to all operations necessary to remove sand, scale and excess metal from the casting. The casting is separated from the mold and transported to the cleaning department. Burnt 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 ports, is removed. Castings can be upgraded by welding or other procedures. Inspection of the casting for defects and general quality is carried out.
ANOTHER PROCESS-
Before shipping, additional processing such as heat treatment, surface treatment, additional inspection or machining may be carried out as required by the
customer specifications.
customer specifications.
Procedures
Metal forming processes:
Processes that cause changes in the shape of solid metallic articles through (permanent) plastic deformations.
Design: Metal forming process in which the part is a shaped longitudinal prism that undergoes reduction and alteration at its cross
sectional area and shape while being pulled through a shaped converging die.
sectional area and shape while being pulled through a shaped converging die.
Extrusion: Metal forming process by which the
piece is placed in a chamber with an opening and is forced to escape
through the opening, usually being pushed out by a mandrel.
piece is placed in a chamber with an opening and is forced to escape
through the opening, usually being pushed out by a mandrel.
Forging: Metal forming process by which the
The part is placed between an anvil and a hammer and subjected to a compressive force between them.
The part is placed between an anvil and a hammer and subjected to a compressive force between them.
Rolling:
Metal forming process in which the part is a longitudinal prism, which is placed between two opposing circular rollers that rotate in opposite directions, drag the part and force it to reduce crosswise.
section.
section.
Metal forming is typically carried out after the primary processes of powder extraction, casting and compaction and before the finishing processes of metal cutting, grinding, polishing, painting and assembly. With few exceptions, most products in the metal fabrication industry are shaped by forming or by a combination of forming and other processes such as
cutting or joining metals.
cutting or joining metals.
Forming operations are classified as those
processes where the desired shape is achieved through plastic transmission
deformation to the workpiece in the solid state. Sort by
processes where the desired shape is achieved through plastic transmission
deformation to the workpiece in the solid state. Sort by
(1) product,
(2) materials,
(3) forming temperature, and
(4) Nature of deformation (sheet metal versus bulk deformation)
can also be useful.
can also be useful.
However, the boundaries between categories are not perfectly
defined.
defined.
1) More complex shapes, both external and internal, can be molded.
As a result, many other operations such as machining, forging and welding can be minimized or eliminated.
2) due to their physical properties, some metals can only be molded into certain shapes (since they cannot be hot worked into bars, rods, plates or other shapes) from ingot form, as a preliminary to
other processing.
other processing.
3) construction can be simplified. Objects can be cast into a single piece that would otherwise require assembly
of multiple parts if made by other methods.
of multiple parts if made by other methods.
4) casting is a highly adapted process
to the demands of mass production. Large numbers of a given casting can be produced very quickly.
to the demands of mass production. Large numbers of a given casting can be produced very quickly.
5) large, heavy objects can be cast when they would otherwise be difficult or uneconomical to produce.
Benefits
1) no or very little loss of material
2) little or no scrap
3) increased ductility (hot forming of cast ingots)
4) increased strength and hardness
5) high production rate, generates final shape in a short time
6) better mechanical and metallurgical properties (strength, toughness, grain size)
1. limitation on mechanical properties
2. porosity
3. Surface finishing
4. Dimensional accuracy
5. Safety risks to humans
6. Environmental Concerns
Limitations
1) expensive equipment due to the large forces involved
2) only suitable for a large number of parts
3) Large capital expenditure due to heavy presses and dies
1) more uniform properties from a directional point of view
2) strength and lightness in certain light metal alloys, which can only be produced as castings.
3) good bearing qualities are obtained in metal casting
Quality
1) almost network formation
