Imagine this: why can engine components, drive shafts, and the internal gears of mechanical equipment withstand tens of millions of repeated impacts? What ensures the safety of these devices under extreme operating conditions?

When it comes to procurement, many people immediately assume that material is the key factor. While material certainly matters, I’d argue that, in fact, most overlook the importance of craftsmanship.

Today, we’ll discuss a process that enhances the toughness and wear resistance of these components: forging.

When it comes to forging, most people who haven’t been exposed to the process probably picture simply heating iron until it’s red-hot and then hammering it—though that is indeed one form of forging, it hardly tells the whole story.

Forging can be classified into three types based on temperature.

I. Hot Forging (Red Forging)

In other words, the process most people think of involves heating steel to red-hot temperatures to soften it, then hammering and pressing it into shape—commonly used for carbon steels and alloy steels.

1. For smaller products, once the material is heated and softened, even a low-tonnage forging press can quickly achieve the desired shape, making it well suited for small parts and components with complex geometries, such as: Small irregular-shaped components, high-strength bolts (M20 and above), small flanges, etc.

2. For larger products, heavy-duty forging equipment is required, typically with a capacity exceeding 500 tons, for example: Wind turbine foundation, crankshaft, transmission shaft, large flanges, etc.

3. Hot forging offers distinct advantages: because the material is subjected to compressive forces, precise blanking is not required, resulting in lower overall production costs and making it well suited for high-volume manufacturing.

It should be noted that after high‑temperature heating, the product may develop oxide scale, exhibit a rough surface finish, and show significant dimensional deviations. Following hot forging, it typically requires subsequent precision machining on lathes, milling machines, or other equipment.

II. Warm Forging

The difference from hot forging is that the workpiece does not need to be heated to red-hot; it is only brought to a warm‑to‑hot state, making it slightly softer than at room temperature.

This forging process is primarily intended to slightly soften the material, making it easier to shape. It places higher demands on the forging equipment than hot forging, but its advantages are also quite evident.

1. With warm forging, temperature is tightly controlled, virtually eliminating scale and ensuring a clean surface; precise blanking reduces the need for subsequent finishing operations, thereby saving labor hours and other costs.

2. Dimensions are more precise, and batch‑produced finished parts exhibit improved consistency.

3. It should be noted that precise temperature control is critical; uneven heating can easily result in defective products, making this method unsuitable for very large components.

Suitable for: Small and medium-sized gears, sleeves, automotive components, automotive connectors, and more.

III. Cold Forging (Cold Upsetting)

Cold forging differs from the first two forging processes in that the material does not require heating; after blanking, it is directly formed by stamping, relying solely on the equipment’s pressing force.

1. Cold forging offers high precision in blanking, and the formed parts typically require little to no subsequent finishing operations.

2. Cold forging produces no scale; the finished parts can be directly put into service, resulting in high material utilization, fewer process steps, and rapid forming.

3. However, it should be noted that cold‑forming equipment and dies are relatively more expensive, and cold‑forging presses typically have limited tonnage, making them suitable only for high‑volume production of small parts, such as: Small‑size high‑strength bolts (M30 and below), nuts, screws, etc.

Of course, in addition to classifying forging processes by temperature, they can also be distinguished according to other criteria, such as open-die forging, die forging, extrusion forging, and plug‑die forging; however, we will not elaborate on these here.

If you’re interested in forged parts, please contact us—we’d be happy to provide more details.

Longyan Duomeida Technology Operations Department