Forging Processes: Hot vs Cold

Forging definition

A forging process involves shaping metal using localized compressive forces. A hammer or die is used to deliver the blows. The temperature at which forging takes place determines whether it is cold forging, warm forging, or hot forging.

What is forging?

The ancient Mesopotamians used forging to shape metal using compressive, localized forces. Forging has evolved significantly since its origins in the fertile crescent, resulting in a more efficient, faster, and more durable process. Currently, forging is usually performed using electric, hydraulic, or compressed air-powered forging presses or hammers.

This paper focuses on the differences between hot and cold forging processes in stainless steel.

In a forging process, the amount of heat applied to the steel is the main difference between hot and cold forging. Cold forging is used for low-temperature applications, such as rolling, while hot forging is used for high-temperature applications, such as welding. As a result of the cooling process during welding, cold forging produces better welds than hot forging. Furthermore, cold forging produces better diamond blade steels than hot forging because the rolling temperature is lower. New-material steel is special steel produced from scrap, sometimes bought from a manufacturer's scrap inventory or stockpiled from others.

Multiple Blue Rings

Cold forging

Cold forging compresses metal at room temperature, while hot forging requires high temperatures. Hot forging allows the metal to take on more elaborate and complex forms than cold forging due to its high temperature.

Hot Forging

Depending on the type of metal, the hot forging temperature varies. As part of the hot forging process, dies are heated to prevent temperature loss during the process and ensure crystallization does not occur during forming. Metal becomes more ductile when heated. The pressure of the dies transforms the hot metal structure into a more refined grain, resulting in greater yield strength and ductility.

Advantages of hot and cold forging include:

Hot forging. More options for customization and increased ductility for more complex parts – Cold forging. Resulting in high surface quality, little to no waste, and little to no finishing work.

Disadvantages Of Hot & Cold Forging Include:

Hot forging. Heat treatment costs, dimensional tolerances are less precise, warping is possible Cold forging. There are few customization options, residual stress may require heat treatment, and there is a risk of residual stress