Reduction Ratio: Why It Matters When Rolling or Forging Billets
How the reduction ratio between billet and finished section affects soundness, grain and ultrasonic test results.
What it is
The reduction ratio is the cross-section area of the starting billet divided by the area of the finished section, whether it is a rolled shape or a forged part.
Why it matters
Working the steel breaks up the cast structure, closes porosity and aligns grain. More reduction usually gives better soundness and mechanical properties, and better ultrasonic results.
Selecting the billet
Choose the billet section that gives enough reduction for the finished size. A re-rolling mill rolling a small bar needs a smaller billet than one rolling a large section.
Check the requirement
Some standards and customers specify a minimum reduction ratio. Quote it in the order so the section can be matched.
Related guides
How to Choose the Right Billet Size for Forging and Rolling
A method to match billet or bloom section to the finished forging or rolled section, using reduction ratio and yield.
Billet Supply Conditions: Grinding, Heat Treatment and Terms
What to check on a billet order: cutting, heat treatment, spot or full grinding, weight tolerance and the chemistry guarantee.
Continuous Casting Process for Steel Billets
How liquid steel becomes a solid billet in continuous casting, and what controls quality.
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