Custom Large Flanges

Large-Scale Custom Flange Machining

Large-scale industrial applications—such as wind turbine towers, heavy-duty pipelines, and massive pressure vessels—rely on custom flanges to maintain absolute structural integrity and leak-proof seals under extreme pressures.

At Openex, we possess the massive Vertical Turning Lathes (VTLs) and heavy multi-axis CNC drilling centers required to machine enormous custom flanges and forged rings. Whether you need standard large-diameter weld neck flanges or highly complex, non-standard slewing ring bearings, we have the capacity to machine parts up to 8 meters (26+ feet) in diameter with exceptional precision.

Large Flange Manufacturing Specifications

We do not stock off-the-shelf pipe flanges; we contract manufacture massive, custom-engineered flanges to your exact blueprints. Below are our general facility capacities:

Maximum Diameter Up to 8,000 mm (8 Meters)
Flange Types Wind Tower Flanges, Weld Neck, Blind, Slip-On, Slewing Rings, Custom Forged Rings.
Materials Processed Carbon Steel (Q345/S355), Stainless Steel (304/316), Duplex, Alloy Steels, and Titanium.
Machining Tolerances Strict face flatness and highly precise bolt-hole positional tolerances via CNC.
Quality & Inspection CMM Dimensional Inspection, Ultrasonic Testing (UT), Magnetic Particle Testing (MT).

Our Work: Large Flanges

Machined Large Flange on Shop Floor
Heavy VTL Machining of Custom Flange Face
Wind Tower Flange
Multi-axis CNC Bolt-Hole Drilling

The Manufacturing Process

1
Material Prep & Heavy Plate Rolling

Depending on the design, flanges can be machined from massive seamless forged rings, or we can custom roll heavy steel plates into rings and perform full-penetration submerged arc welding (SAW) to close the loop.

2
Vertical Turning Lathe (VTL) Machining

The ring is mounted on one of our massive VTLs. We machine the inner diameter (ID), outer diameter (OD), and face to achieve the necessary surface finish and absolute flatness required for high-pressure mating.

3
CNC Drilling & Tapping

Using gantry mills and specialized drilling centers, we accurately drill and tap the bolt-hole circles. Positional accuracy is critical here to ensure perfect alignment during field assembly.