What Is a Forging Ingot? Types, Sizes and Uses
A plain-language guide to forging ingots: how they are made, what shapes and sizes exist, and where they are used.
Definition
A forging ingot is a block of steel cast in a mould and solidified, which a forge heats and shapes into a part. It is the starting stock for most heavy open-die forgings, such as shafts, rings, discs and valve bodies.
How a forging ingot is made
Scrap and alloys are melted in an electric furnace. The steel is refined in a ladle refining furnace, degassed under vacuum, and poured into ingot moulds. For forging quality, the pour is made from the bottom of the mould, through a runner system, and a hot top at the head keeps the last metal molten so shrinkage collects in the feeder.
Shapes and sizes
Forging ingots come as square, round and fluted sections. Square and fluted ingots are the most common for open-die forging. Mark numbers such as M1.5, M6 or M22 indicate the weight class, from about 1.5 tonne to over 20 tonne with hot top.
Where forging ingots are used
Ring rolling, flanges, crankshafts, rotors, valve bodies, die blocks and heavy engineering parts.
What to specify when buying
Grade and standard, ingot size or finished part weight, quantity, required approvals (IBR, PED, AD 2000), and testing such as ultrasonic inspection and third party inspection.
Related guides
How to Order Forging Ingots: What to Specify
A checklist for buying forging ingots: grade, mark, shape, hot top, approvals, testing and delivery details to include in an enquiry.
Hot Top Forging Ingots: Over Imposed vs Semi Inserted
What a hot top does, how over imposed and semi inserted hot tops differ, and how it affects ingot yield and soundness.
Fluted vs Square vs Round Forging Ingots
Compare fluted, square and round ingots: cooling, cracking risk, forging use and when to specify each.