TP 904L, UNS N08904 , 1.4539 , X1 NiCrMoCu25-20-5,Z2NCDU25-20
|TP 904L, UNS N08904 , 1.4539 , X1 NiCrMoCu25-20-5|
This high-alloy austenitic is very resistant to attack from diluted sulphuric acid, phosphoric acid and
acetic acid. It resists pitting in neutral chloride solutions.Its resistance to stress corrosion cracking in
some hot chlorides is much superior to that of the lower nickel austenites. This steel has good formability
and weldability. This material is present in all common standards like ASTM, DIN, BS and NFA, however with
some differences. Design stresses up to 370°C are included in ASME II.
904L material is characterized by:
-Very good resistance to attack in acidic environments, e.g. sulphuric, phosphoric and acetic acid
-Very good resistance to pitting in neutral chloride-bearing solutions
-Much better resistance to crevice corrosion than steels of the ASTM 304 and ASTM 316 types
-Very good resistance to stress corrosion cracking
The steel should not be exposed to temperatures above about 550 °C (1020 °F) for prolonged periods, since this leads to precipitation of intermetallic phases, which can have an adverse effect on both the mechanical properties and the corrosion resistance of the steel. Minimum proof strength properties at high temperatures are based on datasheets seamless tubes and pipe. Since the tubes have thin walls the values should only be used as indicative values for billets.
Chemical composition (%)
|Grade||Tensile Strength||Yield Strength 0.2%||Elongation -% in 50 mm (min.)||Hardness||Hardness|
|ksi (min.)||Offset ksi (min.)||(Brinell) MAX||(Rockwell B) MAX|
Convert ksi to Mpa Formula: ksi/0.1450377
|Welding filler for welded pipe & tube|
*904L possesses good weldability. Welding should be undertaken without preheating. If welding is correctly performed, there is no need for subsequent heat treatment. The temperature between welding passes should not exceed 100°C (212 F). Suitable methods of fusion welding are manual metal-arc welding with covered electrodes and gas-shielded arc welding, especially the TIG and MIG methods.
|Main fields of application(depending on the specific conditions of use)|
Typical applications for 904L are found in oil refineries and within the chemical and petrochemical industry. 904L is also used within the pulp and paper industry, the mineral and metallurgical industry, the food industry, in seawater cooling and in many other fields.
The grade is an excellent alternative to standard austenitic stainless steels in heat exchangers using high-temperature water with chloride contamination.