6Mo stainless steel pipe (UNS S31254) is a high-alloy austenitic stainless steel designed for maximum resistance to pitting and crevice corrosion. The high levels of chromium, molybdenum, and nitrogen make 6Mo suitable for high chloride environments such as brackish water, seawater, pulp mill, bleach plants, and other high chloride process streams. Material to UNS S31254 is described as a 6Mo super austenitic stainless steel.
The high contents of molybdenum and nitrogen present in 6Mo is what gives this super austenitic alloy an amplified corrosion resistance properties. A benefit of using 6Mo stainless steel pipe is that they tend to exhibit high resistance not only to pitting but also to crevice corrosion.
Specification of ASTM A312 UNS 31254
6Mo stainless steel pipe have been produced according to specification ASTM A312 UNS S31254, they have a much higher tensile strength properties and higher creep-rupture in comparison to the more typical austenitic stainless steels such as 316L.
This specification also takes into consideration every pipe that is produced. For instance, tests like tension test, flattening test, hardness test, flaring test along with a nondestructive electric test or a hydrostatic test are performed on the 6Mo Stainless Steel pipes.
| Processing Method | Seamless and Welded |
| Size Range | 1/2” – 48” / DN15 – 1200 |
| Thickness Schedule | SCH 10S- SCH 160, XXS |
| Length | 6m or 12 m or Random |
| Standard | ASME B36.19 |
Properties of 6Mo Stainless Steel Pipe
Material to UNS S31254 is described as a 6Mo super austenitic stainless steel.
6Mo (UNS S31254) is a super austenitic stainless steel with a high level of molybdenum and nitrogen, providing high resistance to pitting and crevice corrosion as well as high strength compared with conventional austenitic stainless steels such as 316L.
Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | Cu |
| 6Mo (UNS S31254) | MIN | 17.50 | 19.50 | 6.00 | 0.50 | |||||
| MAX | 0.02 | 1.00 | 0.030 | 0.010 | 0.80 | 18.50 | 20.50 | 6.50 | 1.00 |
Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % |
| 6Mo (UNS S31254) | 650 min | 300 min | 35 min |
Inspection of 6Mo Stainless Steel Pipe
6Mo stainless steel pipe is widely used, so ensuring the quality has always been a concern for customers. To ensure that their quality and performance meet usage requirements, a series of experiments and inspections are required.
Typical Manufacturing Specifications
ASTM A213
ASTM A269
ASTM A312
BS EN 10216-5
Applications
Seawater handling systems
Desalination plant equipment
Paper and pulp
Flue gas desulphurisation units in power plants
Chemical processing