Ductile Iron Pipe Mold
A ductile iron pipe mold is a thick-walled forged alloy steel tube used in centrifugal casting machines to form ductile iron pressure pipe. Molten iron is poured into the spinning mold, solidifying against its machined bore. Molds are supplied for both water-cooled and hot (coating) processes, in sizes DN80 to DN2600, machined from 21CrMo10-class forged steel.
| Size range | DN80 – DN2600 |
|---|---|
| Process | Water-cooled (De Lavaud) or hot-process (wet spray) |
| Body | One-piece forging, deep-hole machined bore |
| Bore tolerance | To customer drawing; honed finish available |
| Heat treatment | Quench & temper; bore surface treatment per process type |
| Service life | Typically 3,000 – 8,000 casts, process-dependent |
| Inspection | UT full body, bore dimension report, hardness, MTC 3.1 |
Materials
- · 21CrMo10 forged alloy steel
- · 20CrMo / 30CrMo on request
RFQ Checklist
Include this in your inquiry for a fast, accurate quote
- 01Pipe DN size, socket type and pipe class produced
- 02Casting process (water-cooled or hot) and machine builder/model
- 03Full mold drawing, or sample mold dimensions for reverse engineering
- 04Material grade (21CrMo10 / 20CrMo / 30CrMo)
- 05Quantity per size and annual demand forecast
- 06Required documents (MTC 3.1, UT report, bore dimensional report)
How the mold works
In centrifugal casting, the mold spins at high speed while molten ductile iron is introduced along its length. Centrifugal force distributes the iron evenly against the bore, forming the pipe wall without cores. The mold bore geometry — including the socket profile — is therefore the direct negative of the finished pipe.
Why forged, not cast, mold bodies
A forged 21CrMo10 body gives directional grain flow and freedom from casting porosity — both critical because the bore surface undergoes thousands of rapid heating-cooling cycles. Each mold is rough machined, quenched and tempered, finish bored by deep-hole machining, and shipped with UT and dimensional records.
- What material is used for DI pipe molds?
- The dominant grade is 21CrMo10 forged alloy steel, chosen for thermal fatigue resistance under repeated casting cycles. 20CrMo and 30CrMo variants are used by some pipe plants; we machine to the grade your process specifies.
- Water-cooled vs hot mold — what is the difference?
- Water-cooled (De Lavaud) molds run bare and are chilled externally by a water jacket, giving fast cycles and long life. Hot-process molds are sprayed with an insulating coating each cycle and run hotter, common in smaller-diameter lines. The mold design, wall section and bore finish differ between the two.
- What determines the service life of a pipe mold?
- Thermal fatigue cracking of the bore is the usual life-limiting factor, driven by pouring temperature, cycle rate, cooling uniformity and mold material cleanliness. Vacuum-degassed forged bodies with controlled grain flow and correct bore treatment extend life significantly.
- What HS code applies to ductile iron pipe molds?
- Metal molds for centrifugal casting of ductile iron pipe are classified under HS 8480.49 — molds for metal or metal carbides. The US Schedule B subdivision is 8480.49.0010.