904L Stainless Steel
Izvor: KiWi
Trenutačna izmjena od 17:10, 26. veljače 2014.
Back 904L is a non-stabilised low carbon high alloy austenitic stainless steel. The addition of copper to this grade gives it greatly improved resistance to strong reducing acids, especially sulphuric acid. It is also extremely resistant to chloride attack - both pitting/ crevice corrosion and pressure corrosion cracking. This grade is non-magnetic in all conditions and has outstanding weldability and formability. The austenitic structure also gives this grade excellent toughness, even down to cryogenic temperatures. 904L does have really considerable contents of the higher price components nickel and molybdenum. Several of the applications in which this grade has previously performed nicely can now be fulfilled at lower cost by duplex stainless steel 2205 (S31803 or S32205), so it is employed much less typically than in the previous. Corrosion Resistance Though initially created for its resistance to sulphuric acid it also has a really higher resistance to a wide range of environments. A PRE of 35 indicates that the material has good resistance to warm sea water and other higher chloride environments. High nickel content material results in a significantly greater resistance to pressure corrosion cracking than the common austenitic grades. Browse this link clicky to study the reason for it. For a second way of interpreting this, please check-out: relevant webpage. Copper adds resistance to sulphuric and other minimizing acids, particularly in the really aggressive "mid concentration" range. In most environments 904L has a corrosion overall performance intermediate amongst the common austenitic grade 316L and the extremely very alloyed 6% molybdenum and equivalent "super austenitic" grades. In aggressive nitric acid 904L has much less resistance than molybdenum-free of charge grades such as 304L and 310L. For highest tension corrosion cracking resistance in critical environments the steel really should be answer treated right after cold work. Heat Resistance Great resistance to oxidation, but like other extremely alloyed grades suffers from structural instability (precipitation of brittle phases such as sigma) at elevated temperatures. 904L really should not be employed above about 400°C. Heat Treatment Answer Therapy (Annealing) - heat to 1090-1175°C and cool quickly. This grade can not be hardened by thermal therapy. Welding 904L can be successfully welded by all normal methods. Care needs to be taken as this grade solidifies fully austenitic, so is susceptible to hot cracking, specifically in constrained weldments. No pre-heat ought to be employed and in most cases post weld heat therapy is also not necessary. AS 1554.six pre-qualifies Grade 904L rods and electrodes for welding of 904L. Fabrication 904L is a higher purity, low sulphur grade, and as such will not machine nicely. Despite this the grade can be machined employing regular tactics. Bending to a modest radius is readily carried out. To get other interpretations, people are asked to gander at: url. In most instances this is performed cold. Subsequent annealing is normally not needed, despite the fact that it really should be regarded as if the fabrication is to be used in an atmosphere exactly where extreme stress corrosion cracking situations are anticipated. Applications Common applications contain: • Processing plant for sulphuric, phosphoric and acetic acids • Pulp and paper processing • Components in gas scrubbing plants • Seawater cooling equipment • Oil refinery components.
904L Stainless Steel
