Production and Delivery of Custom S235JR2 Flanges for Danish Pipeline Retrofit

Over the past few weeks, our team at Haihao Group completed production and shipment of a mixed batch of S235JR2 flanges for a Danish pipeline refurbishment project. The order combined several flange types, each with specific machining and finishing requirements.

Main Items Produced:

Rotating flange:

Rotating flanges allow the bolt holes to be rotated into alignment without moving the connected pipe.

• DN100 PN10-PN16
• For steel pipe OD 139,7 x 4 mm
• Hot-dip galvanized
• Overall surface roughness:Ra 3,2
• All holes and edges,chamfer 0,5 mm
• Material:S235JR2

Fixed flange:

Fixed flanges are designed for permanent joints where no adjustment is needed once the flange is positioned.

• DN100 PN10-PN16 Closed
• For steel pipe OD 139,7 x 4 mm
• Overall surface roughness:Ra 3,2
• All holes and edges,chamfer 0,5 mm
• Material:S235JR2

Flange collar:

Flange collars serve as joining components that are welded to pipe ends. The client ordered both open and closed designs

• DN100 PN10-PN16
• For steel pipe OD 139,7 x 4 mm
• Overall surface roughness:Ra 3,2
• All holes and edges,chamfer 0,5 mm
• Material:S235JR2

Mounting flange:

• PN10 DN200
• PN10 DN250
• PN16 DN80
• PN16 DN100
• PN16 DN125

Machining and Inspection

Maintaining a uniform Ra 3.2 surface roughness across all flange faces was a key focus. We used controlled turning followed by surface blasting before galvanizing.

After galvanizing, each piece was re-measured to confirm no excess build-up on gasket surfaces or inside the bolt holes. Bolt circle dimensions were checked with a template gauge. All chamfers (0.5 mm) were inspected visually and measured randomly in each batch.

To meet the client’s fit-up requirements, bore diameters were cross-checked with reference pipes, especially on the rotating flange hubs. We know from experience that minor mismatches here can create field installation delays.

Packaging and Traceability

Given the mix of flange types and sizes, we separated them into clearly labeled pallets. Each label included:

• DN and PN designation
• S235JR2 material code
• Hot-dip galvanized finish
• Batch and heat numbers for traceability

Material certificates and inspection reports were compiled into a package that was shared with the customer before shipment. All items were wrapped in plastic film and secured with steel bands.

While none of these flanges are exotic, the combination of requirements—rotating flange alignment, surface roughness, chamfer precision, and galvanizing uniformity—makes production more demanding. Small oversights in any of these areas can create real issues when the parts reach the installation site.

If your project requires S235JR2 rotating flanges, fixed flanges, or custom flange collars with specific bore dimensions and corrosion protection, we have experience handling these details end-to-end. Email:sales@haihaogroup.com