Products
Grey iron casting +
Ductile iron casting +
Carbon steel casting +
Alloy Steel casting +
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Ductile Iron Flanges

Ductile iron flanges are critical components used to connect pipes, valves, pumps, and other equipment in piping systems. Known for their excellent mechanical strength, impact resistance, and sealing performance, ductile iron flanges are widely used in water supply, wastewater treatment, gas distribution, fire protection, and industrial piping systems.

They are compatible with various international standards including ANSI, DIN, BS, and ISO, making them suitable for global markets.

Product Description

Key Features

  • High tensile strength and good ductility for pressure-bearing connections

  • Superior impact and fatigue resistance in harsh operating environments

  • Excellent sealing surface finish ensures leak-free connections

  • Compatible with gaskets and fasteners for easy installation

  • Suitable for both buried and above-ground piping systems

  • Cost-effective alternative to forged steel flanges in medium-pressure applications

  • Available with anti-corrosion coatings for extended service life

Production Process
1. Pattern Design and Manufacturing

3D models are created based on customer drawings, considering shrinkage and machining allowance.
Patterns are CNC-machined from wood, aluminum, or resin, depending on accuracy and production volume. Wood is used for small batches, aluminum for durability, and resin for complex, high-precision parts.
2. Molding

Green sand molding is used for standard shapes and high-volume production, offering good economy and speed. Resin sand molding is selected for complex geometries or tighter tolerance needs.
Cores are made when internal passages are required. Core shooting machines produce sand cores using cold-box or hot-box technology, which are then precisely placed into the mold before pouring.
3. Melting and Pouring

Grey iron is melted in a medium-frequency induction furnace. The raw material mix typically includes pig iron, scrap steel, and recycled castings to ensure stable composition.
Molten iron is poured into the prepared molds at controlled temperatures, usually between 1350°C and 1450°C, to ensure smooth flow, complete filling, and minimal casting defects.
6. Machining (if required)

CNC machining is applied to critical surfaces to achieve required tolerances and finishes. This includes milling, turning, and surface grinding as needed.
Holes are drilled and threads are tapped according to drawing specifications. Additional treatments such as deburring or surface coating may also be performed upon request.
5. Cleaning and Fettling

Castings are cleaned by shot blasting to remove sand residue, scale, and oxides, revealing the metal surface underneath.
Fettling involves removing gating systems, risers, and any excess material using cutting tools or grinders. Care is taken not to affect dimensional accuracy.
4. Cooling and Shakeout

Castings are cooled in the mold under controlled conditions to minimize internal stress and distortion. Cooling time varies depending on part size and wall thickness.
After cooling, molds are broken apart and the castings are removed. The sand is separated and recycled for use in future molds.
1. Pattern Design and Manufacturing

3D models are created based on customer drawings, considering shrinkage and machining allowance.
Patterns are CNC-machined from wood, aluminum, or resin, depending on accuracy and production volume. Wood is used for small batches, aluminum for durability, and resin for complex, high-precision parts.
2. Molding

Green sand molding is used for standard shapes and high-volume production, offering good economy and speed. Resin sand molding is selected for complex geometries or tighter tolerance needs.
Cores are made when internal passages are required. Core shooting machines produce sand cores using cold-box or hot-box technology, which are then precisely placed into the mold before pouring.
3. Melting and Pouring

Grey iron is melted in a medium-frequency induction furnace. The raw material mix typically includes pig iron, scrap steel, and recycled castings to ensure stable composition.
Molten iron is poured into the prepared molds at controlled temperatures, usually between 1350°C and 1450°C, to ensure smooth flow, complete filling, and minimal casting defects.
6. Machining (if required)

CNC machining is applied to critical surfaces to achieve required tolerances and finishes. This includes milling, turning, and surface grinding as needed.
Holes are drilled and threads are tapped according to drawing specifications. Additional treatments such as deburring or surface coating may also be performed upon request.
5. Cleaning and Fettling

Castings are cleaned by shot blasting to remove sand residue, scale, and oxides, revealing the metal surface underneath.
Fettling involves removing gating systems, risers, and any excess material using cutting tools or grinders. Care is taken not to affect dimensional accuracy.
4. Cooling and Shakeout

Castings are cooled in the mold under controlled conditions to minimize internal stress and distortion. Cooling time varies depending on part size and wall thickness.
After cooling, molds are broken apart and the castings are removed. The sand is separated and recycled for use in future molds.
Quality Control

Quality Inspection

  • Chemical Composition Testing: Verified with spectrometer

  • Mechanical Testing: Tensile strength, elongation, Brinell hardness

  • Dimensional Inspection: Calipers, gauges, and CMM used for key dimensions

  • Sealing Face Inspection: Flatness and surface roughness testing

  • Bolt Hole Alignment Check: Ensures perfect assembly fit

  • Visual and Magnetic Particle Testing: Detects surface defects and cracks

QC
QC
QC
Packing and Delivery

Rust Protection Treatment
Before packaging, all castings undergo anti-rust treatment to ensure corrosion resistance during transportation and storage. Common treatments include applying anti-corrosion oil or a water-based rust inhibitor, especially for machined surfaces and critical contact areas.

Secure and Export-Ready Packaging
Each product is carefully packed in fumigation-free wooden crates or reinforced wooden pallets to ensure safety during handling and long-distance shipping. The packaging is compliant with international export standards (ISPM-15) and suitable for sea, air, or land transport.

  • Heavy or large parts are secured with steel straps and foam pads to prevent shifting or collision.

  • Small and medium-sized castings are individually wrapped and separated with protective padding to avoid surface damage.

  • If required, desiccant or shrink film is added inside the packaging to control moisture.

Customized Labeling and Marking
We provide customized labels, barcodes, and product markings based on customer requirements. Typical markings include:

  • Part number and revision code

  • Purchase order number

  • Heat number or batch number for full traceability

  • Customer logo or destination tags (if needed)

Lead Time
Standard lead time is 45 to 55 working days, depending on:

  • Order quantity

  • Whether machining or special testing is required

  • Pattern availability and casting complexity

Urgent delivery requests or phased shipments can be arranged upon agreement.

Packing
Packing