Mandrel forging, sometimes known as saddle forging, is a forging operation that is performed with the help of a tool called mandrel.
A mandrel is a blunt ended tool or rod that is used to enlarge or retain the cavity in a hollow metal product during forging. By the process of mandrel forging, a weld-less, seamless ring or a tube can be produced.
The structure of the mandrel is such that it is tapered on the outside, in order to facilitate easy removal of the worked piece after forging. Mandrels are usually made of hot-work tool steels or medium carbon steel. This article will elaborate on the technique and applications of mandrel forging.
Technique of Mandrel Forging
The set up for mandrel or saddle forging consists of a sizing block, saddle support and top and bottom flat dies. The top and bottom dies form a V shaped combination.
The work piece is positioned on the mandrel, with a hole in the center of the mandrel for cooling purposes. In seamless ring forging, the work piece is expanded and the cross-section is pierced. The exterior and interior of the ring can be forged using a mandrel and wheels or rollers. The forging is done by progressive reduction of the distance between the mandrel and the rollers.
In seamless tube making, the mandrel is held in place by a long rod, while the work piece is moved with the help of a ram, such that the mandrel pierces through the work piece to form a hollow tube.
Some of the major industrial applications of mandrel forging are listed below:
- Making of gear blanks, bearing races, valve bodies, wheels, and turbine components
- Piercing to form seamless tubes
- Ring rolling
- Hollow forging
Sources and Further Reading