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Propeller Shafts

Using only the finest quality virgin steel, BT Marine shaft assemblies are supplied in diameters from 25mm to 300mm. One piece shafts are available in lengths up to 14 meters. Shafts can be supplied in a variety of styles from plain tapered and precision ground to stepped or sleeved dependant on upon the method of lubrication and application. All of our shaft assemblies are supplied complete with keys, coupling nuts and propeller cone nuts and can be ordered with compliance to any IACS society.

We can offer the following materials:

Mild Steel 070M20 (1.0402):
Traditional mild steel for use in sealed grease or oil lubrication systems. Shaft life can be extended by fitment of bronze or stainless steel sleeves by way of bearing areas. In applications where the shaft will be subject to saltwater exposure, it can be wrapped in an GRP epoxy cladding for protection.

Stainless Steel: S304 (1.4301):
Marine shaft material for water, grease, or oil lubrication offering fair resistance to corrosion and moderate wear properties.

Stainless Steel: S431 (1.4057):
A high strength stainless steel for use in situations where the shaft torque and power dictate that the use of mild steel is not possible, offers moderate resistance to corrosion.

Stainless Steel: S316 (1.4401/1.4436):
Traditional marine shaft material for water, grease, or oil lubrication offering good resistance to corrosion and good wear properties.

Stainless Steel: 17/4ph (1.4542):
A martensitic, chromium-nickel-copper precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance.

Duplex F.51 (1.4462):
A modern high strength stainless steel alloy offering excellent resistance to corrosion with outstanding wear properties, particularly useful for high speed, and high power applications where smaller shaft diameters are desirable to reduce drag from underwater hardware.

Super Duplex F.55 (1.4501):
Another modern Super-high strength stainless steel alloy offering excellent resistance to corrosion with outstanding wear properties, particularly useful for high speed, and high power applications.

Below is a table of typical mechanical properties for the materials:

Material 070M20 SS304 SS431 SS316 17/4ph F.51 F.55
Tensile Strength (N/mm2) 430 505 >800 550 >930 700 >805
0.2% Yield Stress (N/mm2) 215 215 >600 240 >724 >450 >530
% Elongation 15 70 14 60 16 40 25

 

BT Marine Propellers Ltd.
Propulsion Technology Centre, Black Swan Road, Dawlish, United Kingdom, EX7 0GF
Tel: +44 (0)1626 864378    |   info@btmarinepropellers.co.uk