Propeller Shaft Coupling Flange

Specifications

Key features

• Integral cast hub and flange body eliminates the hub to plate weld found in fabricated flanges, removing a known fatigue initiation point in the driveline.
• Bore is finish machined to H7 on the shaft fit, giving a repeatable interference or shrink fit without hand fitting at the yard.
• Bolt holes are drilled and reamed on a CNC machining centre with the bolt pitch circle held to +/- 0.05 mm, so fitted bolts seat evenly and share load.
• Mating face is turned perpendicular to the bore axis, holding face runout within 0.03 mm and preventing the cyclic fretting that loosens coupling bolts.
• Near-net casting reduces machining allowance to 2 to 3 mm, cutting machining time and cost while keeping sound material at the hub and rim.
• Optional static balancing to ISO 1940 G6.3 or better, with correction by machining rather than added balance weights.
• Serialised identification and a machined datum pad, so the flange can be re-verified at overhaul without re-establishing set-up.

Applications

• Main propulsion shafting on cargo vessels, tugs and ferries.
• Intermediate and tail shaft couplings on workboats and dredgers.
• Azimuth thruster and Z-drive input couplings.
• Moreover, Pump and gearbox drive couplings in marine machinery spaces.
• Offshore winch and mooring equipment drivelines.
• Generally, Generator and auxiliary drive shaft connections.
• Additionally, Retrofit and repair spares for existing shaft lines.

Quality & compliance

Ningbo Ruican supplies castings and machined parts to shipyards, shaft line manufacturers and marine gearbox builders; class society approvals such as ABS, DNV, LR, BV, RINA, ClassNK, KR and CCS are obtained by the customer or jointly on a project basis, and Ningbo Ruican does not hold class type-approval certificates as a company. We deliver each propeller shaft coupling flange with EN 10204 3.1 certification covering chemical composition, mechanical properties and heat treatment record, with EN 10204 3.2 available when a third party inspector or customer surveyor witnesses testing. Heat lot traceability connects the finished flange to its melt, normalising and tempering furnace chart and machining record, and non-destructive examination options include ultrasonic testing of the hub and rim, magnetic particle inspection of the flange face and bore, and hardness verification to ASTM E18 in the heat treated condition.

Every flange ships with a dimensional report covering bore diameter and fit class, bolt pitch circle, bolt hole diameter and position, face runout and overall thickness, plus the balance record where balancing is specified. Contact Wendy She at sales@cnsandcasting.com or WhatsApp +86-13777124360.

FAQ

Q1. How do you hold concentricity and face runout on a coupling flange?
The casting is finish machined in a single set-up where size allows: the hub bore is bored first, then the mating face is turned and the bolt circle drilled on the same axis. We hold bore to H7, bolt pitch circle to +/- 0.05 mm and face runout to 0.03 mm, with every part verified on CMM before shipment.

Q2. Should I choose WCB, 316L or duplex for a coupling flange?
ASTM A216 WCB is standard for inboard shafting where the flange is painted inside the shaft tunnel. Where the flange runs wet or bilge exposed, 316L (ASTM A351 CF3M) resists corrosion without coating. Duplex 2205 or 17-4PH suits high torque or weight sensitive installations needing a smaller flange.

Q3. Can you machine the bolt holes to suit fitted bolts?
Yes. We drill undersize and ream the holes to the fitted bolt diameter on your drawing, typically H7 or H8, with the pitch circle held to +/- 0.05 mm. We also machine the bolt shank seating and can supply the flange with a matched bolt set, so the yard receives a ready to fit assembly.

Q4. Do you balance the coupling flange?
Static balancing to ISO 1940 G6.3 is available as standard, with finer grades on request for high speed shafts. Correction is done by machining the flange rim rather than welding or bolting on balance weights, which avoids extra stress raisers and preserves coating integrity.

Inspection and documentation

Q5. What non-destructive testing do you perform?
Typical packages include 100 percent ultrasonic testing of the hub and rim to a customer specified acceptance level, magnetic particle inspection of the bore, flange face and fillet radii, and hardness testing to ASTM E18. Dye penetrant replaces magnetic particle on austenitic and duplex stainless grades.

Q6. Can you supply under EN 10204 3.2 with surveyor witness?
Yes. EN 10204 3.1 is standard, and we regularly support EN 10204 3.2 with independent agencies or a customer nominated surveyor who witnesses mechanical testing, NDT and final dimensional inspection. We schedule the visit around our heat treatment and machining plan and issue the full package on completion.