Piercing
A pierced hole has grain flowing around it; a drilled hole cuts straight through the grain. On loaded parts that difference matters.
Piercing punches a hole through a hot forging using a punch, displacing metal outward rather than removing it. It is the first stage in producing a ring, and a way of forming holes without drilling.
- Definition
- Punching a hole in hot metal
- Metal
- Displaced, not removed
- Grain
- Flows around the hole
- Used in
- Ring rolling first stage
Piercing at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Definition: Punching a hole in hot metal
- Metal: Displaced, not removed
- Grain: Flows around the hole
- Used in: Ring rolling first stage
Displacing Rather Than Removing
The punch pushes metal aside, so grain flows around the hole rather than being severed by a cutting edge. The material displaced thickens the surrounding section instead of becoming swarf.
First Step in Ring Rolling
A rolled ring begins as an upset billet that is pierced to create the central hole. That pierced doughnut is then expanded on the ring rolling mill into the finished ring.
Topics covered on this page
- piercing forging
- what is piercing forging
- punching holes forging
- hot piercing
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is piercing in forging?
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Punching a hole through hot metal with a punch, displacing material outward so grain flows around the hole rather than being cut.
How does a pierced hole differ from a drilled one?
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Pierced holes have grain flowing around them; drilled holes sever the grain, reducing strength at the hole.
Where is piercing used?
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In ring production as the first stage, and wherever a hole benefits from uninterrupted grain flow.