What is the Difference Between Casting and Forging?

There are two primary means of fashioning metal into functional, usable shapes in industrial terms. The first is casting. This is the process most people unfamiliar with metalwork are familiar with. The metal or ore is heated until completely liquid. Then it is moved and poured via gravity into a cavity already pre-shaped as expected. When the metal cools, it hardens and takes on the shape of the mold. Forging, alternatively, also uses hot metal but instead of letting it completely liquify, the metal is heated enough to shape it with hammering, compression, or extreme pressure. 

The Advantages of Forging

As noted above, forging involves force to form metal into a desired shape. It’s been a practice used for centuries, most notably for battle weapons and armor in ancient times. Today’s forging still borrows many techniques from those early days, simply using technology and automation to apply greater pressure than could be applied by hand. 

With modern forging, specific and local compression is applied with power hammer or a prefabricated die to force the shape of the hot, malleable metal. There are different types of forging, and they generally vary based on the temperature level used in the process. Both hot and warm forging soften the metal before the force is applied. Cold forging does not. Forging has and continues to be the primary form of mass production when it comes to steel parts and tools that are used for application. However, in recent times forced metal products have also started finding a place in mechanical assembly as well, an arena that was predominantly cast metal fabrication. Why? The demand for higher strength has forced the need for better alternatives. The benefits are clear in this regard:

• Forged productions have quarter greater percentage strength than the same form being produced in cast form
• Forging produces parts with an almost 40 percent greater fatigue strength before failure essentially generating a far longer use life for the same part or tooling
• Cast steel products have two-thirds of the strength of steel, much of it due to how the molecular structured changes under forging which does not occur with poured molds
• Forged metal will last almost up to 60 percent longer in duration and resistance to pulling forces before warping and weakening

The primary cause of forging’s strength comes in how it is produced. Melted metal frees up and liquifies, allowing the molecules of the metal to move freely. That in turn creates a connection or network of molecules that are more random in nature when the metal hardens again. It can also create weaknesses. With a forging process, the molecular structure is never allowed to get to a randomized state. Instead, the network stays aligned and tight as it was originally. The pressure and compression force causes the molecular network to tighten even more, making the metal harder and harder with each forging cycle. Again, in ancient times, this is how some of the hardest swords and armor were produced, and it’s also what contributed to amazing armor technology in the 20th century.

Casting Advantages

Give the above, one might wonder why use casting at all. Not every metal application needs incredible strength, however, and it can be very expensive to use forging exclusively. Again, casting allows metal to be shaped by transforming it to a molten form and then pouring it into the cast of a pre-formed shape. The cast or die is in negative form. This ensures that the metal, when it hardens, will form into a positive result, which is what can be used functionally. Casting allows for easy fabrication of metal parts and assembly that would otherwise cost too much using alternative methods. 

Casting can be performed in a number of procedures. A lost-casting essentially destroys the mold when the metal hardens; it is basically broken or peeled off the hardened end-product making the mold consumable as a one-time use. There is also a die or hard mold casting which can be re-used. Centrifugal casting forces the liquid metal into the cast form using spinning and gravity. These and many other methods fall into one of two categories: expendable and consumable casting forms. 

Casting also provides the advantage of product production that is far larger than can be produced with forging efficiently. Casting also provides a solution for metal parts that are just too complicated to forge and hammer into production. It’s also quite useful when the metal mixture involves unique or uncommon alloys.

A Valuable Metal Production Service Reliably Available

Beginning in 1979 and since, Cliffe Metal Products, Inc. has been producing both forged and casted metal products and parts for customers and clients of all types. The high quality and value Cliffe Metal Product delivers has repeatedly and consistently performed beyond expectations. Much of that is due to experience, extensive tooling capability, and maintaining production at ISO-9002 certification levels. 

Cliffe Metal Products also provides customers a capable platform for producing unique and custom fabrications not available anywhere else or uniquely needed for specific applications. The eye to detail and partnerships have allowed Cliffe to excel in multiple industries and fields of demand versus just addressing one type of metal manufacturing demand alone. 

And when it comes to large size productions and manufacturing, and CNC machining services, Cliffe Metal Products can provide the correct and most efficient means of production that works best for your design, specifications, production run order and application. Whether you need centrifugal castings, large custom metal parts, metal spun components, open die forgings, and rolled ring forgings are all possible with our assembly processes and facilities.