Forging Process | Surfing Solutions

1. Die Design and Making

Designed from Your DrawingThe die is drawn around your part, with a slight taper on the walls so the forging lifts out.
Stock for MachiningExtra metal is left on every face that will be machined.
Room for the FlashA gutter round the cavity takes the metal squeezed out between the dies.
Hardened Tool SteelThe dies are machined from tool steel and hardened to take the blows.
Who Owns the DieYou do, once it is paid for. We keep it safe at the manufacturer, use it only for your parts, and send it to you or to another manufacturer if you ask.

Steel with a Mill CertificateEvery bar comes with the steel mill’s certificate for its heat.
Cut to WeightThe bar is cut by saw or by shear to the weight each forging needs, so every piece fills the die the same way.
Traced by Heat NumberThe heat number follows the cut pieces, so each forging can be traced to its certificate.
Check AnalysisA sample of the steel is analysed again to confirm the mill’s figures.

Forging TemperatureSteel is heated to about 1,100 to 1,250 °C, depending on the grade.
Induction or Gas FurnaceInduction heats each piece fast and evenly, with little scale on the surface.
Temperature CheckedEach piece is checked on its way to the hammer or the press.
Never Too Cold or Too HotSteel forged too cold can crack, and steel heated too hot grows a coarse, weak grain.

Hammer or PressThe hot piece is struck by a hammer or squeezed by a press between the two dies.
Step by StepTwo or three impressions often bring it closer to the final shape each time.
FlashThe extra metal squeezes out round the parting line as flash.
Grain FlowThe grain follows the shape of the part, so a forging is stronger than the same part cut from bar.
Typical PartsCrankshafts, connecting rods, gear blanks, flanges and steering knuckles.

Flat DiesThe metal is worked between flat or simple dies that do not enclose it.
Drawn, Upset and SteppedThe piece is turned and moved between blows to lengthen it, to shorten and widen it, or to step it down.
No Shaped Die NeededIt suits large parts and short runs.
Typical PartsShafts, discs, blocks, sleeves and rolls, forged with stock left for machining.

Upset and PiercedA round piece is upset, then pierced to open a hole in the middle.
Rolled to SizeOn the ring rolling mill the wall is squeezed thinner and the ring grows in diameter until it reaches your size.
One Piece, No WeldThe ring has no joint anywhere, and the grain runs round it.
Typical PartsBearing rings, gear ring blanks, and rings for flanges and slewing bearings.

Trimmed While HotStraight after forging, a trimming press cuts the flash off round the parting line.
PiercedA punch removes the thin web of metal left in any hole.
CoinedSome parts are pressed once more to bring a face or a thickness closer to size.
RecycledThe flash is sold as scrap and melted again.

NormalisingHeated and cooled in air, for an even, fine grain in carbon steel parts.
Quench and TemperHardened in water, polymer or oil, then tempered, for strength and toughness in alloy steel parts.
Case HardeningA hard, wear resistant skin on a tough core, for gears, pins and king pins.
AnnealingSoftened for easier machining.
Recorded and CheckedEach batch runs to a written cycle, and hardness is checked after it.

CNC Turning and MillingForgings are turned, bored, drilled and milled to the sizes on your drawing.
Threads, Grinding and HardeningThreads cut, faces ground and bearing areas induction hardened where the drawing asks for it.
MeasuredMachined parts are measured against the drawing, with a CMM report when you want one.
Rust ProtectionMachined faces are oiled and wrapped for the voyage.

HardnessChecked on every batch after heat treatment.
DimensionsForged and machined sizes measured against your drawing.
VisualEvery piece looked over for laps, folds and cracks.
Ultrasonic TestingSound sent through the metal finds flaws inside it, every piece for critical parts.
Magnetic Particle InspectionThe part is magnetised and wet with a fluorescent magnetic ink, which gathers along cracks at or near the surface and glows under ultraviolet light.
Tensile and Impact TestsDone on the same heat when your drawing asks for them. The full list is on the Quality page.