How to Choose Casting and Forging？

Classification：BLOG

Castingand forgingare popular metal forming processes used to create parts and components for a variety of industries. However, these processes are very different from each other, and yield products with varying characteristics. As a leading outsourcing authority for metal forming and fabrication, we’re here to clarify what distinguishes casting and forging from each other, and help you decide which is better suited to your project’s requirements. Let’s begin by breaking down the definitions of each.

What is Forging?

Forging uses dies, pressure, and temperature to shape a solid piece of round metal bar into a shape. There are three ways forging can be classified: 1) temperature (hot, warm, or cold forging), 2) type of process (open or closed die forging), or 3) material used (steel forging, aluminum forging, brass forging, or bronze forging). 

What is Casting?

Casting is the process in which molten metal is poured into a hollow cavity mold and later cooled to form a solidified part. Types of casting vary based on the molding materials, casting process, and filling pressures. Die casting, investment casting, permanent mold casting, and sand castingare the main metal casting methods.

Forged vs Cast

To summarize, castings are melted, poured, and solidified, while forgings are physically forced into a shape while remaining in a solid state. As a result, these two processes form end products with very different characteristics. When deciding which process is best suited to your project, it’s important to narrow down your priorities. Is it a complex shape? Is it large in size? Does it require high levels of strength? Refer to the chart below for the most common considerations to keep in mind when choosing between casting and forging.

Factors to Consider When Choosing Between Casting & Forging

	Metal Forging	Metal Casting
Structural Integrity	Far superior in strength compared to castings. High level of material predictability	Products tend to be more porous and more susceptible to breakage compared to forgings
Tolerance	Not well suited to highly complex geometries	Allows for a high level of detail. Able to adhere to tight tolerances
Product Size	Limited in terms of the size and thickness of the metal (larger = more difficult)	Compatible with a wide range of sizes
Material Selection	Selection of alloys is limited	Compatible with nearly all types of metal
Secondary Operations	Usually requires secondary operations to refine and finish product to exact specifications	Provides primary product that will usually require very few secondary operations
Cost	Tends to be most cost effective for medium to large production runs	Generally, less expensive compared to forging, but it depends on the specific casting method used.

Grain Flow as a Factor

Grain flow is at the center of what separates these processes from each other. In forging, the metal is pounded and deformed, but the grain flow remains unbroken, allowing it to retain its strength. In casting, the metal is melted down, which breaks the grain flow and causes the metal to lose some of its initial strength once it solidifies. As a result, forged metal is less likely to shatter than cast metal.

Which is Better, Casting or Forging?

All in all, casting tends to be the less expensive, more versatile option, however; forging offers superior strength and wear resistance. The question of which is better depends on the top priorities for your project. If low cost, exotic alloys, and complex geometries are a priority, casting would probably be the way to go. However, if strength and structural integrity are concerned, forging may be the better option.

Explore examples of our past workto see what Googletech’s metal forging sourcing services can do for you and your planned project.

Advantages Of Metal Casting Process

• Metal castings have an extremely high upper size limit in casting weight (if none).

• Large range of alloy choices.

• Tooling costs in the metal casting process are often less expensive than forging dies.

• For forgings, custom alloys are more difficult to produce whereas with casting, alloys including nickel, chrome, and moly can be added at the melting stage.

• Smaller production runs are not a problem.

• Extremely adaptable to mass production needs.

• Complex parts and/or thin walled parts are typically not a problem.

• Liquid metal can be formed into variety of shapes, allowing greater flexibility in part design.

• Modifications of part designs and molds are easier and quicker to implement.

• Post-casting results are close to design specifications, reducing time spent on secondary processing/operations.

• Cast parts are typically lighter than forgings.

• Lead times can be shorter, especially in the case of centrifugal castings.

Advantages Of Metal Forging Process

• Metal Forgings generally, have higher mechanical properties and better ductility (depending on alloy).

• Will typically handle impact better than castings.

• Continuous grain flow and finer grain size.

• Forging metal usually eliminates the occurrence of porosity, shrinkage, cavities, and cold pour issues.

• Greater wear resistance due to grain flow.

• In some cases, metal forgings can be cheaper than castings.

Summary

Other Problems

How do you identify forging and casting?

Casting is the process in which metal is heated in a furnace until molten. While in the liquid state, the metal is poured in a die, or mold, to create a component shape. Forging is the process in which thermal and mechanical energy is applied to ingots to cause the alloy to change shape while in a solid state.

Forging is stronger than casting.

Forged parts had a 37% higher fatigue strength resulting in a much longer lifespan than cast parts. Cast iron only had 66% of the yield strength of forged steel, a measurement that indicates the load amount metal can hold before deforming.

What are the advantages of casting over forging?

Castings have a more precise forming size than ordinary forgings and welding parts. Parts can be cast as single pieces rather than an assembly of various parts if produced from other methods. Tooling can be tailored to meet quantity demands. Parts can be cast in quantities ranging from 1-100's.

What are the four 4 basic types of forging?

There are four types of forging manufacturing processes that are commonly used to shape metal parts. These processes include impression die forging (closed die), cold forging, open die forging, and seamless rolled ring forging.

What is cheaper casting or forging?

Casting tends to be generally cheaper than forging, but there are many methods of casting, including investment casting; die casting; permanent mold; and vacuum process molding, which can all affect pricing, tensile strength, and cosmetic appearance.

How do you choose the casting method?

The casting process selection decision will be constrained in part by a range of geometric features, such as minimum section thickness and minimum core size, but also by achievable quality, taking account of surface finish, porosity, etc, and production parameters, such as sample lead-time and economic production run.

Which is better forging or casting?

Forged steel is generally stronger and more reliable than castings andplate steel due to the fact that the grain flows of the steel are altered, conforming to the shape of the part. The advantages of forging include: Generally tougher than alternatives. Will handle impact better than castings.

How to Choose Casting and Forging

here are 5 things to consider when deciding if a casting or forging is right for your component, application, and overall needs.

1. Size of the Finished Product.

2. Design of the Component.

3. Alloy Selection.

4. Internal Strength of the Component.

5. Cost of Castings vs. ...

6. Advantages of Metal Casting Process.

Discuss Your Forging or Casting Needs with Googletech

With over 30 years of industry experience, Googletech is an expert on castings and forgings. As a leading outsourcing authority, we can find a domestic or international manufacturer to take care of all your metal forming needs. We provide hands-on facilitation from initial design all the way through fulfillment to ensure you receive the high quality products you need. Backed by our quality guarantee, we can make certain the parts you receive match your exact specifications, or your money back. Contact us today for a free, no obligation consultation.