What does “forged” and “cast” mean though? And how does that affect the performance of a club? We will answer those questions and a few more in our short explanation!
Firstly, both these phrases refer to separate manufacturing processes. These processes apply to much more than simply golf equipment. Many of the metal objects in your life are created via forging and casting. Both processes also inherently impart different material properties to the metal.
Forging refers to a process in which a material is usually heated, while maintaining a solid state, and then forced into the shape desired. Now to explain better, we must put on our material engineering hats.
Metals have a crystalline structure. You can think of it like wood. Wood has grains and those grains are oriented in a certain pattern. Therefore, the strength of wood depends on how those grains are oriented. For example, it is much easier to splinter a log for firewood when the grains are oriented vertically. Metal is the same way. If you examine metal under a microscope it will have the same grains that you associate with wood.
When metal ingots are formed, special attention is made to create a uniform and consistent crystalline structure. The grain sizes are similar and flow together. As previously stated, this maximizes the strength, consistency, and durability of the metal.
Now when you forge something out of that metal ingot, you heat the ingot to make it malleable but not enough to break apart the crystalline grain structure. Think of a blacksmith. Blacksmiths heat metal till its red hot and then form it on an anvil. This is forging. You do not see them melting the metal into a liquid. By keeping the metal, a solid throughout the entire process, it ends up being a much stronger object. Therefore, swords, knives, etc. have historically been forged.
Casting an object requires building a mold and pouring liquid metal into it. This process is great, as it allows for easy manufacturing and the creation of complex parts with hollow chambers such as with an engine block of a vehicle. The manufacturer can use a meltable material such as wax inside a sand mold to form these complex shapes.
Unfortunately, once the metal becomes a liquid the crystalline grain structure breaks down. As a newly formed cast object cools down and becomes a solid again, the grain structure reforms but this time much more randomly and inconsistent. There also is the potential for trapped air to create weak points. The metal becomes more like particle board or cardboard in terms of structure than a normal piece of wood.
Now does this make cast parts weak? Absolutely not. Over the past couple thousand years, humans have gotten pretty good at making cast metal parts. Ventilation holes, vacuum pressure, and other advances increase the quality of cast metal. As stated, cast metal is what vehicle engine blocks are made from those are expected to withstand extreme stress and strain.
While cast parts are not weak, forged parts are certainly stronger. How much stronger is a complicated question that is dependent on many factors. However, you can typically expect somewhere between 25-50% higher strength on a forged part compared to a cast one. Forged products are also less brittle than their cast counterparts. The uniform grain structure allows for more flex before it cracks.
In the golf industry, many people claim that forged clubs have a much better “feel”. This can be attributed to the consistent grain structure. However, the limitations of the forging process prohibit certain shapes and designs that are engineered for maximum forgiveness. All in all, we recommend trying out both forged and cast irons and seeing if you can feel the difference.