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P.O. Box 537
Plymouth, IN 46563
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Plymouth Foundry: Navigating Metal Forming – A Guide on Hot vs. Cold Forging Processes

Plymouth Foundry: Navigating Metal Forming – A Guide on Hot vs. Cold Forging Processes

As discussed in Thomasnet’s article “Hot Forging Vs. Cold Forging,” hot forging and cold forging represent two distinct metal forming techniques, each yielding comparable outcomes. Forging, a process of shaping metal into predetermined forms using various tools and equipment, offers options of hot, cold, or warm forging methods based on specific application requirements. Manufacturers assess multiple factors before determining the most suitable forging approach, considering aspects such as grain structure alignment and directional properties imparted to the part.

Forging encompasses various processes, including upsetting, drop forging, and press forging. In upsetting, a horizontal movement of a hammer or ram presses against the end of a rod or stem to widen and reshape it, commonly used for producing high-strength bolts and engine valves. Drop forging involves hammering the metal in a die to achieve the desired shape, akin to a blacksmith’s hammer forging against an anvil. Distinctions are drawn between open-die and closed-die forging, with the latter constraining the metal between die halves.

Hot forging involves significant heating of the metal, typically above its recrystallization temperature, to facilitate plastic deformation without strain hardening. This process allows for the creation of intricate shapes while maintaining metal ductility and malleability. Isothermal forging, a variant of hot forging, employs die heating to prevent surface cooling during forging, often used for super alloys. Controlled atmospheres may also be utilized to minimize scale formation during forging.

In contrast, cold forging is performed at or below room temperature, offering advantages in dimensional control, surface finish, and contamination management. Despite the versatility of cold forging, it demands robust equipment and may necessitate intermediate anneals for certain metals.

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Photo and article with all rights reserved, courtesy of thomasnet.com