ASTM A677 Stainless Steel Alloy 904L SS 1.4539 Welded Tubing ERW
Alloy 904L is a low carbon, high alloy austenitic stainless steel
which is widely used in applications where the corrosion properties
of AISI 316L and AISI 317L are not adequate.
The addition of copper to this grade gives it corrosion resistant
properties superior to the conventional chrome nickel stainless
steels, in particular to sulfuric, phosphoric and acetic acids.
Good resistance to oxidation, but like other highly alloyed grades
suffers from structural instability (precipitation of brittle
phases such as sigma) at elevated temperatures. 904L should not be
used above about 400°C.
Solution Treatment (Annealing) - heat to 1090-1175°C and cool
rapidly. This grade cannot be hardened by thermal treatment.
904L can be successfully welded by all standard methods. Care needs
to be taken as this grade solidifies fully austenitic, so is
susceptible to hot cracking, particularly in constrained weldments.
No pre-heat should be used and in most cases post weld heat
treatment is also not required. AS 1554.6 pre-qualifies Grade 904L
rods and electrodes for welding of 904L.
904L is a high purity, low sulphur grade, and as such will not
machine well. Despite this the grade can be machined using standard
Bending to a small radius is readily carried out. In most cases
this is performed cold. Subsequent annealing is generally not
required, although it should be considered if the fabrication is to
be used in an environment where severe stress corrosion cracking
conditions are anticipated.
Typical applications include:
· Processing plant for sulphuric, phosphoric and acetic acids
· Pulp and paper processing
· Components in gas scrubbing plants
· Seawater cooling equipment
· Oil refinery components
· Wires in electrostatic precipitators
Table 1.Composition ranges for 904L grade of stainless steel.
|904L||min. max.||- 0.020||- 2.00||- 1.00||- 0.045||- 0.035||19.0 23.0||4.0 5.0||23.0 28.0||1.0 2.0|
ASTM A213/A269, ASME SA213 AVG wall, NACE MR0175/MR0103
|ALLOY 904L (UNS N08904) CHEMICAL COMPOSITION % (MAX.)|
|THEORETICAL BURST PRESSURE|
|OUTSIDE DIAMETER (OD)||OD TOLERANCE||WALL TOLERANCE|
|UP TO 1/2"||+/- .005"||+/- 15%|
|1/2" to 1-1/2" EXCL.||+/- .005"||+/- 10%|
Acid Production, Fertilizer Processing, Oil Refining, Pulp and
Paper Processes, Gas Scrubbers, Seawater Cooling Equipment, Control
|Outside Diameter (OD)||Wall Thickness|
|1/4"- 1"||.035" - .065"|
|Cold Finished and Bright Annealed Tube|
|YIELD STRENGTH 0.2% OFFSET (MINIMUM KSI)||31|
|TENSILE STRENGTH (MINIMUM KSI)||71|
|ELONGATION (MINIMUM 2 INCHES)||35%|
|Alloy 904L is non-magnetic in all conditions and has excellent
formability and weldability. The austentic structure also give this
grade excellent toughness, even down to cryogenic temperatures.|