Product Overview
The CQ 3-inch IPS Ductile Iron Backup Ring SDR7 is intended for HDPE flange adapter connections. This product is also referred to as a Backup Flange or Backing Flange.
Technical Specifications
- Product Type: Ductile Iron Backup Ring
- Pipe System: IPS
- Size: 3"
- SDR: SDR7
Dimensions


| 3" SDR7, IPS Backup Flange | ||
|---|---|---|
| Dimension | Value | Metric |
| Outside Diameter (OD) | 7.5 in | 190.50 mm |
| Thickness (T) | 0.94 in | 23.88 mm |
| Inner Diameter (I.D.) | 3.60 in | 91.44 mm |
| Holes (N) | 4 | — |
| Bolt Hole Diameter (B.D.) | 0.75 in | 19.05 mm |
| Bolt Circle Diameter (B.C.) | 6.00 in | 152.40 mm |
| Radius (R) | 0.40 in | 10.16 mm |
| Unit Weight (lbs/kgs) | 3.8 lb | 1.72 kg |
| Pressure Class (PC) | 335 | — |
| FM Rating (psi) | FM(200psi) | — |
Material
Material: Ductile Iron
Material Grade: ASTM A536 Grade 65-45-12
Drilling Standards
- ASME/ANSI B16.5
- ASME/ANSI B16.47
- ASME B16.1
- AWWA C207
Finish
Default Finish: Epoxy Powder Coating
Average coating thickness: 120 μm (applies only to Epoxy Powder Coating).
Optional Finishes:
- Primer
- E-Coating
- Galvanizing
- Hot-Dip Galvanizing
Application
HDPE flange adapter connections
Design Simulation
Design simulation of the ductile iron backup ring under modeled conditions.

Available Options
CQ Brand Identification
CQ branded products are marked for product identification and traceability.

Quality Control
Representative quality-control and handling references:
- Dimensional Inspection
- EN 10204 3.1 Material Certificate
- Appearance and Surface Inspection
- Protective Packing
- Product Photos Before Shipment







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