The Difference in Cold, Warm and Hot Forging

Compare the processes, benefits, and effects of forging at cold, warm, and hot temperatures.

COLD FORGING

Cold forging involves either impression die forging or true closed die forging with lubricant and circular dies at or near room temperature. Carbon and standard alloy steel forgings are most commonly cold-forged. Cold forged steel parts are generally symmetrical and rarely exceed 25 pounds. The primary advantage of cold forging steel is the material savings achieved through precision shapes that require little finishing. Completely contained impressions and extrusion-type metal flow yield draftless, close-tolerance components. Production rates are very high with exceptional die life. While cold forging usually improves mechanical properties, the improvement is not useful in many common forging applications and economic advantages remain the primary interest. Tool design and manufacture are critical.

WARM FORGING

Warm forging has a number of cost-saving advantages which underscore its increasing use as a manufacturing method. The temperature range for warm forging of steel extends from above a household oven temperature to below the recrystallization temperature, which is about 800 to 1,800 degrees Fahrenheit, depending upon the alloy. However, the narrower range of from 1,000 to 1,330 degrees Fahrenheit is emerging as the range of perhaps the greatest commercial potential for warm forging of steel alloys.

Compared with cold forging, warm forging has the potential advantages of reduced tooling loads, reduced forging press loads, increased steel ductility, elimination of need to anneal prior to forging, and favorable as-forged properties that can eliminate heat treatment.

HOT FORGING

Cold, Warm, and Hot Forging

Hot forging is the plastic deformation of metal at a temperature and strain rate such that recrystallization occurs simultaneously with deformation, thus avoiding strain hardening. For this to occur, high workpiece temperature (matching the metal’s recrystallization temperature) must be attained throughout the process.

Isothermal Forging

A form of hot forging is isothermal forging, where materials and dies are heated to the same temperature. In nearly all cases, isothermal forging is conducted on superalloys in a vacuum or highly controlled atmosphere to prevent oxidation.

Aluminum Hot Forging

Aluminum hot forging is a unique and propriety process developed by Queen City Forging, whereby rapid Infrared heating is used to enhance physical properties for aluminum forging.

Which Type of Forging is Right For You?

Not sure if cold, warm or hot forging is right for your project? As a leading forging company in the United States, Queen City Forging can help you determine the best forging process for your needs. Our expertise provides innovative, cost-competitive solutions that produce a quality forge for OEMs, every time. Contact us or request a quote today.