Auxiliary Operations – Metallurgical Processes

Auxiliary operations are processes that are performed on forgings to obtain surface conditions or shapes that cannot be achieved using regular forging operations. Auxiliary forging operations are usually carried out in forging presses, such as a wide ram forging press.

Commonly performed auxiliary operations include pre-forming, setting, sizing, piercing, and trimming. This article will look into the various auxiliary operations, and their advantages and applications.

Types of Auxiliary Operations

Common auxiliary operations are described below:

Pre-forming

Pre-forming of metals is a process of producing a prototype of the final product. Pre-forming operations encompass bending and crushing, performed with the help of a press ram.

Sizing

Sizing provides a metal workpiece with better dimensional accuracy and surface finish. This operation is performed at temperatures far below the melting point of the metal and is a squeezing operation which is performed in an open die by applying pressure on the metal. Ferrous metal castings are sized to flatten holes around piercings and sharpen corners.

Piercing

Piercing is a shearing process in which a punch and die are used on a metal workpiece. After the metal has been pierced by a punch, the piece of metal that is removed by the punch is treated as scrap. Piercing can be done on various parts of the metal workpiece.

Trimming

Trimming is the process of shearing off excess material from a metal workpiece and is performed to provide a better finish. Trimming, usually performed on a trimming press, helps complex shapes to conform to specifications.

Advantages of Auxiliary Operations

Some of the advantages of auxiliary operations are listed below:

• Provides better surface finish to the workpiece
• Helps to make the metal conform to the specified dimensions.

Industrial Applications

Some of the industrial applications of auxiliary operations are listed below:

• For removing flash from impression die-forged metal parts
• For creating holes in metal.

Sources and Further Reading

• Manufacture of Heavy press forgings – Massachusetts Institute of Technology
• Technology of Metal Forming Processes – Surender Kumar
• Trimming - Stalcop