UNS N08367/AL-6XN/25-6HN Stainless Steel

UNS N08367 is a type of high Molybdenum containing super austenitic stainless steel that has nickel as the base metal. This alloy has nickel-chromium-iron as the primary constituents. By varying the other elements, it can be designed to resist attacks from specific chemical reagents. This alloy exhibits high strength even at high temperatures. 6% Mo, high Ni, and N alloyed austenitic grade with extremely high resistance to both uniform and localized corrosion. Commonly used in applications to withstand chlorinated sea water and also used in flue gas cleaning.

UNS N08367 Chemical Composition:

Ni Cr Mo C N Mn Si P S Cu Fe
23.5-25.5 20-22 6.0- 7.0 0.03 Max 0.18-0.25 2.00 Max 1.00 Max 0.040 Max 0.030 Max 0.75 Max Rem.

UNS N08367 Mechanical Properties:

Temp. °F (°C) Ultimate Tensile Strength, psi 0.2% Yield Strength, psi Elongation in 2”, percent Charpy V-Notch Toughness, ft-lb
-450 (-268) 218,000 142,000 36 353*
-320 (-196) 196,000 107,000 49 85
-200 (-129) – – – 100
70 (21) 108,000 53,000 47 140
200 (93) 99,900 49,400 47 –
400 (204) 903,000 40,400 46 –
600 (316) 86,000 36,300 47 –
800 (427) 87,000 36,000 48 –

UNS N08367 is also known as super-austenitic stainless steel. This alloy contains a higher content of Molybdenum and Nitrogen (so it is also called 6% Mo Super Austenitic Stainless Alloy, AL-6XN, NAS 254NM, INCOLOY alloy 25-6HN, F62). These additions enhance the thermal stability and corrosion resistance of the alloy. Among super austenitic stainless steels, UNS N08367 offers a higher degree of corrosion resistance and strength.

UNS N08367 Specifications:

Form Standard
Metal Type UNS N08367
Bar ASTM B691 / ASME SB691
Wire ASTM B691 / ASME SB691
Sheet ASTM B688, A240 / ASME SB688, SA240
Plate ASTM B688, A240 / ASME SB688, SA240
Tube ASTM B676 WELDED
Pipe ASTM B675 WELDED
Fitting ASTM B366 / ASME SB366 / ASTM B462 /   ASME SB462
Forging ASTM B472 / ASTM B462 / ASME SB462

Machinability

Machining of UNS N08367 should be done at a slightly lower speed when compared to 316 stainless steel, as it has high strength.

Welding

UNS N08367 can be welded by shielded metal arc welding, gas tungsten arc welding, submerged arc welding, plasma arc welding and gas metal arc welding. The filler metal and electrodes are usually made of INCONEL alloy.

Hot-working

UNS N08367 can be hot worked at temperature ranges of 982-1232°C (1800-2250°F).

Annealing

UNS N08367 should be annealed at temperatures greater than 1121°C (2050°F).

Applications

In applications to withstand chlorinated sea water
Flue gas cleaning
Process equipment in chemical industry
Bleaching equipment in the pulp and paper industry
Desalination
Seawater handling
Hydrometallurgy
Food and beverage
Pharmaceuticals
Heat exchangers