Corrosion and Oxidisation Resistance of 303 Stainless Steel
303 stainless steel shows good corrosion and oxidisation resistance in mildly corrosive atmospheric environments. Its sulphide inclusions act as pit initiation sites meaning it provides a lot less resistance than 304. But normally the most frequently used and lowest grade is 201 and 304 austenitic stainless steel. 303 stainless steel is barely used. Here just a introduce.
Sulphur additions to the composition act as initiation sites for pitting corrosion. This decreases the corrosion resistance of grade 303 stainless steel to less than that for 304. However corrosion resistance remains good in mild environments. In chloride containing environments over 60°C, grade 303 stainless steel is subject to pitting and crevice corrosion. Grade 303 stainless steel pipes is not suitable for use in marine environments.
Grade 303 should not be exposed to marine or other similar environments, to prevent rapid pitting corrosion.
1.4305 303 stainless steel provides good oxidisation resistance in intermittent service to 760°C (1400°F) and continuous service to 870°C (1,598°F). The use of 303 stainless steel is not recommended in the range of 425-860°C (797-1580°F) due to carbide precipitation.
303 is susceptible to sensitisation.
Corrosion Resistance
Intergranular corrosion may be compromised if the material is heated between 800°F (427°C) and 1650°F (899°C) or cooled slowly through that range.
The following table is for reference only, many factors can affect the corrosive resistance. A corrosion test for each application should be applied.
303 due to its higher sulphur content has lower resistance to all corrosion types than 304, and indeed all of the 300 series austenitic stainless steel.
Its selection therefore is generally based upon its excellent machinability, coupled with its lower corrosion resistance.
N.B. It is most important that oxygen is always allowed to circulate freely on all stainless steel surfaces to ensure that a chrome oxide film is always present to protect it. If this is not the case, rusting will occur as with other types of non stainless steel.
For optimum corrosive resistance surfaces must be free of scale and foreign particles. Finished parts should be passivated
Mechanical Properties
Physical Properties
Resistance to Corrosion
Heat Treatment
Machinability
Fabrication
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