904L Stainless Steel Pipes and Tubes
Product Standard: ASTM B677 , ASME SB677
Main steel grades: 904L
Corrosion Resistance:
Although originally developed for its resistance to sulphuric acid it also has a very high resistance to a wide range of environments. A PRE of 35 indicates that the material has good resistance to warm sea water and other high chloride environments. High nickel content results in a much better resistance to stress corrosion cracking than the standard austenitic grades. Copper adds resistance to sulphuric and other reducing acids, particularly in the very aggressive "mid concentration" range.
In most environments 904L has a corrosion performance intermediate between the standard austenitic grade 316L and the very highly alloyed 6% molybdenum and similar "super austenitic" grades.
In aggressive nitric acid 904L has less resistance than molybdenum-free grades such as 904LL and 310L.
For maximum stress corrosion cracking resistance in critical environments the steel should be solution treated after cold work.
Heat Resistance:
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 400C.
Heat Treatment:
Solution Treatment (Annealing) - heat to 1090-1175C and cool rapidly. This grade cannot be hardened by thermal treatment.
Welding:
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.
Fabrication:
904L is a high purity, low sulphur grade, and as such will not machine well. Despite this the grade can be machined using standard techniques.
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.
Chemical Composition & Mechanical Properties:
| C | Cr | Cu | Mn | Mo | Ni | P | S | Si |
| Max | | | Max | | | Max | Max | Max |
| 0.02 | 19.0-23.0 | 1.0-2.0 | 2.0 | 4.0-5.0 | 23.0-28.0 | 0.045 | 0.035 | 1.0 |
Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness |
| Rockwell B (HR B) | Brinell (HB) |
| 904L | 490 | 220 | 35 | 70-90 typical | - |
| Rockwell Hardness value range is typical only; other values are specified limits. |
Application:
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
Typical Application:
Production and transport of sulfuric acid
Metal pickling in sulfuric acid
Production and concentration of phosphoric acid
Use in seawater, brackish water, condensers, heat exchangers and pipe work in general
Paper and allied industries
Gas washing
Chemical and pharmaceutical industries
Mark: As required.
Inspection and Test: chemical composition test, mechanical properties test(tensile, yield, elongation), process properties test(flatting, flaring, bending, hardness, impact, etc.), appearance and size test, non-destructive inspection test, hydrostastic test.
Delivery status: Annealed, normalized, normalized+Tempered, etc.
Surface treatment: oil impregnation, paint, passivation, phosphating, shot blasting etc.
Packing: Exporting package/wooden box /as requirement.
Product Tags:
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904L 1/2NB -1NB Stainless Steel Seamless Pipe For Seawater Cooling Equipment Images
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