What is the Hot and Cold Metal Forging Process?

Metal Forging has been a known skill of homo sapiens since ancient times. Forging is the process of forming and shaping metal pieces using many compressive methods.

This used to be the work of a blacksmith who, with his hammer and other tools, forged metal pieces for vast household purposes.

The Forging Processes can be classified as hot, cold, and warm considering the amount of temperature used during forging.

The deciding factor of using either hot or cold forging depends on the industry in which the metal is to be used.

What is Cold Forging?

It is an economical and efficient way of manufacturing the desired shape and size metal piece. Moreover, the result is sturdier and more high-quality than machining or casting.

  • Cold forging is the process of using compressive forces to shape the desired metal at room temperature.
  • The metal piece is squeezed between two shapes namely punch and die.
  • The piece is squeezed till it attains the shape of the die piece.
  • The techniques for cold forging include rolling, drawing, pressing, spinning, extruding, and heading. Extruding cold forging is mainly used in manufacturing parts in the automobile industry.

Manufacturing Process by Cold Forging

  • Cutting the Edges

Not all metal pieces are of the same size as desired by the customer. The extra edges of the metal pieces are cut according to the desired dimensions.

Further, the confirmations are made considering the volume and the type of material used.

  • Lubrication

The cut metal piece is lubricated to prevent it from sticking to the die piece. Lubrication also ensures that the metal piece is at room temperature and does not heat up under high pressure.

It depends on the forging units to choose the type of lubricant. However, it is not generally used.

  • Fixing the metal piece to the die

After lubrication, the metal piece is placed on the workpiece. One of the dies is fixed to the hammer on top of the workpiece. The other one is kept below the metal piece to be forged.

  • Striking Process

The striking mechanism of the hammer applies pressure on the metal piece and shapes it according to the die.

The hammer follows a hydraulic, mechanical, or pneumatic mechanism. The striking speed is less than a millisecond.

  • Flash Removal

After forming the desired shape of the metal piece, it is removed from the workpiece. The extra flattened metal outside the shape is called flash.

Flash is either removed by the conveyor or by a robotic hand. This makes it further cost-effective.

What is Hot Forging?

  • Hot forging is the process of shaping metal pieces into desired shapes by heating them at different temperatures for different metals.
  • Because of the existence of heat, the metal pieces are molded effortlessly and even form complex shapes.
  • The high temperatures help in avoiding strain on the metal piece because of the elevated pressure.
  • It further lowers the stress flow and the amount of energy exuded by the hammer on the metal piece.
  • The hot forgings are of two types. This includes the open die forging and the closed die forging.

Manufacturing Process of Hot Forging

The manufacturing of the metal piece using hot forging is almost similar to cold forging.

The only sweeping difference is the exposure of the metal piece to higher temperatures. The slab is heated to the required temperature to improve malleability.

Choosing Hot or Cold Forging Process

The cold forging increases the strength of the metal at room temperatures. As for hot forging, it prevents the metal piece from strain hardening at higher temperatures.

It entirely depends on the forging units to Choose the Forging Method depending on the customer’s demands and requirements. They also might want to consider the cost-effectiveness of both processes.

The gist of the matter

Hot forging is the widely used metal forging method used for heavy-weight components, heavy-duty alloys, and complex components.

If you are looking for a metal forging process for the automobile industry, then hot forging is the right choice.

Murari Engineering Works helps you make the right decision for your business. You must know time is money. So getting an expert opinion will benefit product building.

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