Hot Forging vs Cold Forging: Which Press Process Fits the Part?
Hot forging forms stock after heating it for the planned operation. Cold forging forms stock without that hot-forging heat cycle; coining and sizing may form part of the cold process. These are process choices, not two interchangeable press categories. Select a machine against the part, die and documented working envelope.
Published: 27 Aug 2026
At a Glance
| Criteria | Hot Forging | Cold Forging, Coining and Sizing |
|---|---|---|
| Stock temperature | The billet or preform is heated before the forming operation. The process plan must account for transfer from heating to the die. | The stock enters the process without the hot-forging heat cycle. Check its material condition and the planned sequence of forming operations. |
| Material and deformation | Material grade, starting condition, part geometry, die design and sequence determine the permitted deformation. There is no universal reduction limit for hot work. | Material grade, starting condition, part geometry, die design and sequence determine the permitted deformation. There is no universal reduction limit for cold work. |
| Typical result | The die forms the heated stock into the planned forging. The process engineer must account for the finished-part requirement and the effects of the hot operation. | The operation can form, coin or size the part. The result depends on the tool, material and condition of the machine near the working part of the stroke. |
| Tooling and lubrication | Use dies and lubrication intended for the heated process. Check the die interface and any heating, transfer or spray equipment as separate items. | Use tooling and lubrication specified for the material and operation. Check die fit, slide guidance and ejection against the planned tool. |
| Press types | Hot forging can use different press designs. TRIGA's current hot-forging category includes Farina and TMP Voronezh machines. | Cold forming does not require one universal press type. TRIGA's knuckle-joint category includes Barnaul, Kieserling & Albrecht, Agostino Colombo and TMP Voronezh machines for coining, sizing and related work. |
| Critical selection data | Check the material temperature plan, die envelope, stroke, shut height, table, slide, drive documentation, ejection and part handling. | Check the material condition, die envelope, force and motion requirement, stroke, shut height, table, slide guidance and ejection. |
| Used-machine risks | Inspect the frame, drive, clutch and brake where fitted, ram guides, lubrication and the interface with the planned hot process. | Inspect linkage clearances where fitted, pins and bearing areas, slide guides, ejectors, lubrication and die-height adjustment. |
Hot Forging
Start with the heated-process plan
Define the stock, heating method, transfer sequence and die operation before selecting a press. A hot-forging label does not establish whether a particular closed die, tool height or handling sequence will fit a particular machine.
Inspect the load path and drive
Inspect the frame, ram and guides. Identify the documented drive arrangement, then inspect the clutch and brake where the machine has them, along with the lubrication system and any visible modification or repair. A powered inspection should cover the planned working part of the stroke.
Keep process equipment separate
Heating, transfer, die spraying and part handling may be necessary for the proposed operation, but they are not implied by the press listing. Review their condition, interfaces and documentation as separate equipment.
Cold Forging, Coining and Sizing
Match the operation to the motion
Coining and sizing can need controlled motion near bottom dead centre. A knuckle-joint drive can suit this work, but the part, tool and forming sequence determine the selection. Do not assume that every cold-forging job needs a knuckle-joint press.
Check the linkage and guides
For a knuckle-joint press, inspect the linkage, pins and bearing areas for clearance and damage. Then inspect the slide guides and die-height adjustment. These components affect how the machine carries the tool through the working part of the stroke.
Verify ejection before purchase
Confirm how the part leaves the tool. Inspect the upper and lower ejectors where fitted, their available movement and their interface with the planned die. Bring the die data to the inspection.
Selecting from a Part Drawing
Material and dimensions
Send the material grade and starting condition, plus the blank dimensions and finished-part dimensions. Identify each section where the operation changes the material.
Operation and die data
Describe the proposed operation and sequence. Send the die drawing when available, or provide its outside dimensions, working height, slide interface, table footprint and ejector requirement.
Output requirement
State the required output and the proposed part-handling method. Compare that requirement with the documented cycle capability of the individual machine and the complete operation, rather than a general press type.
Browse Relevant Press Categories
Hot forging presses
See the used hot forging press category for Farina, TMP Voronezh and archive references. Confirm the status and documentation of an individual listing before arranging a visit.
Knuckle-joint presses
See the used knuckle-joint press category for machines from Barnaul, Kieserling & Albrecht, Agostino Colombo and TMP Voronezh. Compare the individual die envelope and condition with the planned operation.
Screw press as a separate option
A screw press is another press design to consider for some forging work. Read the existing screw press vs mechanical press guide for that comparison rather than treating it as part of the hot-versus-cold decision.
Frequently Asked Questions
No. Hot forging describes the process condition of the stock. A press used for that work has a specific drive, stroke, die space and condition that must be checked against the proposed operation.
No. A knuckle-joint press can suit coining, sizing and some cold-forming work because of its motion close to bottom dead centre. Select the machine from the part, material, die and required motion rather than the process name alone.
No. Compare the die-set dimensions, stroke, shut height, table, slide, ejection and handling sequence with the documentation for the individual press. The proposed die and part determine whether the machine is suitable.
Send the material grade and condition, blank and finished-part dimensions, the forming operation, die drawing or die envelope, ejector requirement and output target. This information gives a technical basis for comparing individual machines.
TRIGA can coordinate an inspection with the seller, subject to access and machine status. Share the machine link and the tool data so the inspection can focus on the relevant components and measurements.
Discuss the part and the machine
Send the part drawing, material, die data and output requirement. TRIGA can help you assess individual machines and arrange an inspection.