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The Advantages of Steel Forging vs Casting
Steel casting and steel forging are two distinct processes for manufacturing metal parts, each with advantages and limitations. While both casting and forging processes influence the final shape of a metal workpiece through unique heating and shaping techniques, they feature significant differences. There are many factors to consider when selecting the best method for manufacturing your product, including materials, production volume, product strength requirements, and more. So, which process will best suit your project specifications: casting or forging?
Before deciding which process is best for your application, it's important to consider the differing capabilities of forging vs casting, as well as your project's requirements. Casting vs forging considerations include:
By learning about the advantages and disadvantages of forging vs casting, you can choose the best process for your specific application.
The steel and stainless steel forging process creates parts and components in various shapes and sizes. The steel forging process produces parts with increased strength, better consistency, a tighter grain structure, and increased lifespans through the use of dies, compressive forces, and varying temperatures. There are several different forging processes, including hot, warm, and cold forging, which can be utilized in open-die and closed-die forging. The following table identifies some of the strengths and weaknesses of steel forging.
Forging Advantages
Forging Disadvantages
Reliability &#; Forgings provide consistent ductility, known yields, and increased strength due to grain development.
Lower Tolerance Levels &#; The forging process may create parts that do not meet the requirements for high tolerances.
Structural Integrity &#; Forgings provide increased product strength and a high level of material predictability.
Limitations &#; Forged products may be limited in shape and may include defects from die failure.
Material Cost Savings &#; Materials for forging are generally less expensive than the materials required for casting.
Secondary Operations &#; Forged parts generally require secondary finishing services to meet part specifications.
Open Die Forging
Casting processes utilize a mold that is injected or filled with molten metal. The metal within the mold then cools and solidifies into the form of a molded product. Steel castings are used to create parts that are too complex and intricate for forging processes. Some of the different steel casting processes include die casting, investment casting, and sand casting. The following table identifies some of the strengths and weaknesses of steel casting.
Metal Casting Advantages
Metal Casting Disadvantages
Increased Production Rate &#; Once the cast is created, high volume production rates generally follow.
Higher Costs &#; Initial casting tooling costs can be extremely high, which can make small-run productions difficult.
Higher Tolerances &#; Casting allows for increased tolerances that meet project criteria.
Lower Structural Integrity &#; Casting creates parts that are more porous than forged products.
Less Secondary Work &#; Finished casting products generally require fewer secondary services than forged parts.
Enhanced Process Control &#; The casting process must always be closely monitored to maintain quality assurance standards.
After considering the capabilities and limitations of each process, it's clear that one method isn't necessarily better than the other; instead, it depends on each project's specification requirements. So, which process is suitable for your project?
Forging is an excellent choice if your part or component requires increased strength and reliability with a cost-saving advantage. Forging is versatile and able to create high-strength custom shapes for heavy-duty applications. It is also compatible with many grades of steel and stainless steel. Industries that frequently utilize forging processes to manufacture custom parts include:
Custom Forged Parts
If increased production rates and higher tolerances are needed, casting may be the best option. While casting requires additional time and cost at the front end of the process to create the cast, high-volume production runs can move quickly once the cast is made. Casting can also produce exceptionally tight tolerances, making it an ideal process for small, intricate components. Industries that rely on casting for high-volume production of parts include:
At Great Lakes Forge, we specialize in producing open-die forged parts and components in a wide range of materials. Not sure if forging or casting is the right process for your application? Contact us online or call 800-748-, and our team of metal forging experts will help you determine if forging or casting is the best process for your application. For all your custom forging needs, choose Great Lakes Forge.
Start Your QuoteThere are various characteristics that businesses look for in custom metal parts. Strength, size, material type, grain flow, and cost are some of the most important, and they are determined by the type of processing procedure used.
Forging and casting are the most common.
During the forging process, metal is pressed or hammered to give the desired shape, while in casting it is melted and then poured into a mold shaped in the desired form.
Both processes have particular advantages and disadvantages depending on the characteristics, cost, and service requirements that are needed.
The following sections will cover these key differences specifically in the areas of strength, types, sizes, alloy selection, additional processing, cost, and grain flow.
The stronger material is, the more likely it is to be able to maintain its structural integrity under various harsh conditions. This durability ensures functionality and safety.
Metals should be strong enough to maintain their structural integrity and perform at peak levels both under normal operational conditions and those that exceed them.
There are four ways in which the strength of metal can be measured.
Tensile strength refers to a material&#;s ability to withstand pressure or forces that would normally separate or pull a metal apart.
Compressive strength is the amount of pressure a material can tolerate without fracturing&#;in other words, the load it can bear.
Shear strength denotes the capacity to withstand or resist shear, that is, the structural strain produced by pressure.
Torsional strength is the ability of a material to withstand twisting loads due to torque.
Of the two processes we&#;ve mentioned in the previous section&#;forging and casting&#;forging produces a far stronger metal. This is because the process of forging alters the metal&#;s granular layout within and on top of the surface, making it more uniform.
Forging also helps to eliminate holes (voids and gas pockets) that would normally decrease both the structural and chemical integrity of the material.
On the other hand, the casting process tends to produce more porous holes since the metal shrinks from its thicker to its thinner sections during the process.
If you require strong material to maintain functional and structural integrity under normal and severe conditions such as is the case in the production of aerospace, railway, and ship components, then creating custom metal parts through forging is recommended.
Not all products need to be strong and rigid. Some ought to be more pliable and flexible so they can be formed into complex and aesthetic designs.
For those applications, casting is usually more appropriate, as it is more difficult to shape metals made through forging.
The casting process allows for more complex shapes to be formed since the metal is melted first, which means it can be easily poured into a pre-shaped mold or die.
Moreover, since the metal is melted during the casting process, larger products can be created, even those measuring up to 400 to 4,000 tons.
Therefore, the size of a particular product or application will also dictate which process should be used.
However, casting is not solely delegated to only large-size applications. Since it adheres to very tight tolerances, it is very useful even in forming smaller products with complicated geometrical designs.
Additionally, casting is more cost-effective than other machining processes, including forging, because it promotes material efficiency&#;five times higher than standard machining&#;meaning that more parts can be made in less time.
That is not to say that forging does not have its value, especially when strength and reliability are the primary concerns. It is just that casting is more useful when creating larger products with specific design requirements.
To get a better idea of which process is more useful for your specific project, take a look at the following list of products created through both methods.
Forged ProductsCasted ProductsAgricultural Machinery & EquipmentHeavy Construction EquipmentOil Field ApplicationsHeavy Farming EquipmentHand ToolsHeavy Mining EquipmentGeneral Industrial EquipmentMachining ToolsRailroad EquipmentChemical MachineryOff-Highway EquipmentPetroleum MachineryAerospace ComponentsDefense VehiclesValvesArtilleryFittingsMunitionsElectrical Machines (motors, pumps, generators, compressors)Household AppliancesGardening ToolsArt & Decorative Objects (sculptures, lamps, furniture)To summarize, the forging process is ideal for parts and applications that need to be strong, tough, and resistant to various mechanical forces.
If you are looking for more details, kindly visit Block forging.
On the other hand, casting is ideal for larger parts with detailed and complex shapes, patterns, and internal cavities.
As forging and casting are different processes, they aren&#;t always used with the same types of alloys.
Alloys are a combination of metals and non-metals, which are mixed and blended to enhance the desirable properties of a metal, such as corrosion resistance, tensile strength, and toughness.
It is important to choose the right alloy for your project because doing so will help reduce wear and tear, extend product life, and help increase overall performance.
After the alloy is chosen, the process that best compliments the alloy must be selected. The selection process will primarily depend on whether forging or casting can shape and mold the alloy to exact specifications.
Below is a list of alloy metals that are typically used in the forging process, and those that are more suited for casting.
Alloys Typically Used in ForgingAlloys Typically Used in CastingAlloy SteelNickel AlloysMicroalloy SteelCobalt AlloysStainless SteelAluminum AlloysCarbon SteelLead AlloysAluminumStainless SteelCopperCarbon SteelTitaniumIron (gray, white, ductile)MagnesiumSiliconNickelZincIronMagnesiumCobaltAs you can see in the chart, some alloys are equally suitable for both processes, so the choice of one instead of the other will depend on other factors listed in this guide.
What is more, the above lists are not complete and there are many other combinations of metals and non-metals that can be used for both processes.
In general, forging has a more limited selection when it comes to alloys, while casting can utilize almost any type of metal during its process.
Both forging and casting often rely on secondary operations to complement them. However, forging tends to require fewer of them.
Secondary processes are additional manufacturing processes that are needed to enhance and refine the formed product in some way.
There are many types of those operations, but the most popular ones include:
They provide the following benefits:
The reason forging requires fewer secondary processes lies in the fact that forging methods can be utilized on their own to get as close as possible to the desired specifications.
Of the different forging methods, the most common ones are:
And since these three forging methods pretty much ensure the main aims of forging&#;predictable strength and strong performance&#;not much is needed after they are implemented.
However, some secondary actions are commonly used after the initial forging process is completed.
Punching, straightening, and trimming are often employed after forging to ensure and improve the dimensional accuracy of fittings.
Cleaning methods like blasting, tumbling, or picking may also be used to clean the forgings if needed.
Casting, on the other hand, has more secondary processing requirements that are essential in creating smoother finishes, optimal sizes, and increased protection against oxidation.
The following ones are used most frequently:
The above processes are particularly common in conjunction with casting, since the process itself only deals with the formation of a part, and not its assembly, protection, or final surface finish.
Many custom-metal part manufacturers offer all or most secondary processes that may be required after casting or forging is completed, so there is usually no need to go to a different provider.
When it comes to cost-effectiveness, there is no definitive answer as to which of the two processes is more expensive.
The price of forging or casting will depend on various factors surrounding the formation and completion of a product.
Some of those factors include:
As a general rule, however, forgings are less expensive when they are purchased in medium to large lot sizes and castings are less costly when smaller lot sizes are bought.
However, castings can also be cost-effective when purchased in medium to large lot sizes, depending on how many secondary options are needed after they have been acquired.
As far as the cost of raw materials goes, those required for casting are usually less expensive than those for forging. This is because casting requires fewer initial steps and therefore less machinery to complete.
Also, the preliminary process of turning ingots into billets is eliminated during the casting process.
The price of tooling can also be eliminated for castings since it is usually not needed.
However, keep in mind that some forging methods don&#;t require tooling either, making them cost-competitive with castings. For instance, such is the case with open die forgings (ODF).
The machining costs associated with casting and forging are almost identical. Nevertheless, since forged alloys like stainless steel tend to have finer grains, machining them is often easier and therefore less costly.
Secondary operations will play a major role in the final cost of the manufacturing process.
Since casting tends to require more of them, it can turn out to be more expensive than forging, even though, when no secondary processes are required, its general costs are often lower than those of forging.
Therefore, the final costs depend on which casting method or forging method is chosen, as well as how many of the above-mentioned factors are involved in the overall manufacturing process of a particular application.
This is precisely why it is always recommended to contact a metal manufacturer and ask which variables will most likely pertain to the casting or forging of your specific product.
The information they supply you with will help you determine which one will be more economical for your project requirements.
Grain flows are fiber-shaped lines that appear on metal surfaces in the direction of metalworking (shaping) during the forging process.
Grain flow can help strengthen metal surfaces, reduce fatigue, and increase mechanical properties.
Casting, however, does not produce any grain flow and therefore does not provide its benefits to the formed product.
What is more, because there is no grain flow, casting can result in metallurgical defects, such as:
The directional strength (directional alignment or grain flow) produced during forging creates a refined microstructure on the surface of the metal. This gives it higher tensile strength, impact toughness, fracture toughness, fatigue strength, and ductility.
Additional benefits that are derived from directional grain flows include:
Applications such as surgical and dental instruments, hand tools and hardware, as well as aerospace and automotive components need the additional properties produced by grain flow.
It ensures their functionality under harsh conditions and increases their longevity of use.
Unlike casting, which produces a random grain distribution that reduces impact strength, forging helps to produce longitudinal grain flow across metal surfaces.
This greatly increases their overall strength and resistance to impact.
Therefore, if higher strength, toughness, and fatigue resistance are primary requirements, then forging would be the obvious choice.
The casting process will not be able to supply any grain flow and so none of the required attributes.
Neither of the metal manufacturing processes is categorically better than the other.
Instead, you can choose between casting or forging depending on the type, size, alloy composition, cost, and strength that your project requires.
You may need other secondary manufacturing processes apart from casting and forging to fulfill the demands of your project, which will also affect the time and the resources it takes to complete it.
Since there are so many variables affecting the formation of custom metal products and parts, it is best to consult a metal manufacturer to help you determine which process is best suited for your application and budget.
If you want to learn more, please visit our website Custom Universal Joints.