Why investment casting
Sea-water service calls for duplex steels, nickel-copper alloys and aluminium bronzes, which investment casting shapes into deck, pump and propulsion hardware.
Components
- Deck and rigging hardware
- Propeller and waterjet parts
- Seawater pump and valve components
Materials
CF8M, duplex, nickel-aluminium bronze, silicon bronze, Ni-Cu alloys.
Frequently used alloys
| Grade | Type | Standard |
|---|---|---|
| CF8M | Mo-bearing austenitic stainless steel, cast 316 type 316 type | ASTM A351/A351M, A743/A743M |
| CD3MN (4A) | 22Cr-5Ni-Mo-N duplex stainless steel 2205 type (Uranus® 45N, SAF 2205®) | ASTM A890/A890M, A995/A995M Gr. 4A |
| C95800 | Nickel-aluminium bronze | ASTM B148 |
| CuAl10Fe5Ni5-C (CC333G) | Nickel-aluminium bronze | EN 1982 |
| M-35-1 | Nickel-copper alloy, cast Alloy 400 type Monel® 400 type | ASTM A494/A494M |
Typical requirements
Pitting and crevice corrosion in seawater, galvanic compatibility and, where required, classification-society material approval.
- Pitting and crevice resistance
- Classification society rules where specified
- Polished or passivated finish
Related engineering topics
International equivalents
How to compare cast alloy designations across EN, DIN, ASTM, ASME, UNS, AISI, SAE, JIS, ISO and GB/T, and why similar grades are not automatically interchangeable.
Material testing
Verification of cast alloys: spectrometric chemical analysis, PMI, tensile, hardness and impact testing, metallography, ferrite measurement, corrosion tests and heat-treatment verification.
Surface finish
Surface texture of investment castings: Ra and Rz, typical as-cast, blasted, ground and machined conditions, how to specify surface requirements and visual acceptance standards.