A pump shaft is one of the hardest material selection problems in rotating equipment. It carries torque and bending, it fatigues, and it does all of that immersed in whatever the pump is moving.
Super duplex is the sweet spot for pump shafts because it delivers strength, wear resistance and corrosion resistance at once. The grade now known as Alloy 32760 was originally developed by a pump manufacturer, Mather and Platt of Manchester, for large centrifugal pump bodies.
Which alloy is best for a pump shaft?
Super duplex is the default. Alloy 32750 (F53) and Alloy 32760 (F55) give a minimum yield of 80 ksi with a PREN above 40. Ferralium® 255-SD50 is preferred in larger sections.
Where a non-magnetic or higher strength shaft is required, Fermonic® 50 HS delivers higher yield while remaining fully austenitic.
Which alloy for seawater, desalination and firewater pumps?
Super duplex throughout for wetted parts, with Hiduron® 130 and Hiduron® 191 for shafts, wear parts and seal components where galvanic compatibility with copper alloy casings matters. Both resist crevice corrosion and biofouling, which is decisive on pumps that sit idle between duty cycles. Hiduron® 130 also retains its impact strength down to minus 196°C.
Which alloy for chemical and process pumps?
Alloy 825 and Alloy 625 for acid and chloride bearing streams. Alloy 2205 covers a large amount of general process duty where full super duplex is not commercially justified.
Which alloy for wear rings, sleeves and anti-galling parts?
Fermonic® 60 (Nitronic® 60) is the answer wherever metal-to-metal contact is the failure mode, because it runs against stainless steel without seizing. Hidurel® 5 covers bearings and bushes. For sleeves and spacers, Alloy 316L (hollow bar) - sold by some suppliers as Sanmac® 316L, a trademark of Alleima - removes the boring operation entirely, which on a repeat build programme is a larger saving than the material price difference.
What bar sizes are available for long pump shafts?
Send us the size and we will confirm from current stock. Long shafts and large impeller blanks are usually available from one piece rather than being fabricated or forged; we saw to length before despatch.
Also known as
Alloy 32760 is equivalent to UNS S32760, also known as Zeron 100®, a trademark of Rolled Alloys, and originally developed by the pump manufacturer Mather and Platt. Alloy 32750 is equivalent to UNS S32750, also known as SAF 2507®, a trademark of Alleima. Ferralium® 255 is the Langley Alloys trade name for UNS S32550. Fermonic® 50 and Fermonic® 60 are our designations for UNS S20910 and UNS S21800, known elsewhere as Nitronic 50 and Nitronic 60, trademarks of Cleveland-Cliffs (formerly AK Steel). Hiduron® 130 meets DIN 2.1504 and DTD 900/4805 (also designated UNS C72400).
Typical pump components
Shafts, shaft sleeves and spacers, impellers and impeller blanks, wear rings and neck rings, casing and casing cover components, gland followers and lantern rings, seal components, thrust collars, tie bolts and casing bolting, bearing housings.
Why pump manufacturers buy from us
- Bar in large diameters, so long shafts and large impeller blanks come from one piece - send us the size and we will confirm from current stock.
- Alloy 316L hollow bar in a wide range of sizes, removing the boring operation on sleeves, spacers and bushes.
- Call-off and consignment arrangements for repeat build programmes.
Our stock range is bar, plate and pipe, so we supply impeller blanks and machined-from-solid components rather than castings.
