Cast duplex stainless steels are also referred to as duplex stainless steel castings and duplex alloy steel castings.
The duplex stainless steel alloys have a mixed microstructure of austenite and ferrite, the optimal ratio is 50/50, however in actual duplex stainless steel castings the ratio may be 40/60 or 60/40. The cast duplex stainless steels offer a combination of enhanced mechanical properties and corrosion resistance when properly balanced in composition and properly heat treated, cast duplex stainless steels have roughly twice the yield strength compared to austenitic stainless steel castings, and also have better resistance to localized corrosion, particularly pitting, crevice corrosion and stress corrosion cracking.
The standard ASTM A890 covers a group of cast duplex stainless steels for general application, because of the possibility of precipitation of embrittling phases, the grades included in ASTM A890 are not recommended for service at temperatures above 600 degrees Fahrenheit.
Magsen Foundry are able to supply finished size and fully machined duplex stainless steel castings that fully meet the ASTM A890 standard, including:
- ASTM A890 Grade 1A, CD4MCu, Type 25Cr-5Ni-Mo-Cu
- ASTM A890 Grade 1B, CD4MCuN, Type 25Cr-5Ni-Mo-Cu-N
- ASTM A890 Grade 1C, Type 25Cr-6Ni-Mo-Cu-N
- ASTM A890 Grade 2A, Type 24Cr-10Ni-Mo-N
- ASTM A890 Grade 3A, Type 25Cr-5Ni-Mo-N
- ASTM A890 Grade 4A, Type 22Cr-5Ni-Mo-N
- ASTM A890 Grade 5A, Type 25Cr-7Ni-Mo-N
- ASTM A890 Grade 6A, Type 25Cr-7Ni-Mo-N
- ASTM A890 Grade 7A, Type 25Cr-7Ni-Mo-Cu-N