Carbon steel suffer from 'general' corrosion, where large areas of the surface are affected. Stainless steel tubes in the passive state are normally protected against this form of attack, however, localised forms of attack can occur and result in corrosion problems.
The assessment of corrosion resistance in any particular environment, therefore, usually involves a consideration of specific corrosion mechanisms.
These mechanisms are principally:
Other related mechanism can also occur, which include:
- Erosion - corrosion
- Corrosion fatigue
Localised corrosion is often associated with chloride ions in aqueous environments. Acidic conditions (low PH) and increases in temperature all contribute to localised mechanisms of crevice corrosion and pitting corrosion. The addition of tensile strength, whether applied by loading or from residual stress, provides the conditions for stress corrosion cracking (SCC). These mechanisms are all associated with a localised breakdown of the passive layer. A good supply of oxygen to all surface of the steel is essential to maintaining the passive layer but higher levels of chromium, nickel, molybdenum & nitrogen all help in their individual ways to prevent these forms of attack.
Resistance to localised forms of corrosion
As a general rule increased corrosion resistance can be expected by moving through the grades:
| 1.4512 to 1.4016 |
409 to 430 |
increasing chromium from 11 to 17% |
| 1.4301 |
304 |
adding nickel which aids the reformation of the passive layer if it is disturbed |
| 1.4401 |
316 |
adding molybdenum reduces the effectiveness of chloride ions in locally breaking down the passive layer |
| 1.4539 and 1.4547 |
904L and 6% molybdenum grades |
further increases in chromium, nickel and molybdenum result in overall improved localised corrosion resistance |
Duplex grades such as 2205 (1.4462/S31803) are specifically designed to combat SCC by 'balancing' the structure to increase its strength, but additionally molybdenum and nitrogen enhance the pitting resistance, which in turn has the additional benefit in improving their SCC resistance.
Use of stainless steel under high temperature condition refer table
Corrosion Resistant Stainless Steel Tube
Corrosion Resistance of Stainless Steel Tubes
Seawater Resistance of Stainless Steel Tubes
High Temperature Stainless Steel Tubes
High Temperature Stainless Steel Tubes
High Temperature Property Stainless Steel
Heat resistant Stainless Steel Tubes
Welded Stainless Steel Pipe
U-bend Stainless Steel Tubes
Heat Exchanger Tubes
Duplex Stainless Steel Tubes
Boiler Tubes, Condenser Tubes
Corrugated Seamless Stainless Steel Pipe Tube
DIN 2391 Seamless Precision Steel Tubes
DIN2391 Seamless Pricision Steel Tube Tubing Tubes
Alloy 400 Properties and Corrosion Resistence
Non Acid-resisting Stainless Steel Tube
Bright Annealing Stainless Steel Tubes
High Temperature-Tubes and Pipes Standards
Heat Resistant Stainless Steels and Corrosion Resistant Stainless Steels-Valve Steels,Iron Baes Super alloys
Metallographic Test - Metallography Testing
Metallographic Test Report
Stress Corrosion Cracking (SCC)
Chloride Stress Corrosion Cracking
Stainless Steel Corrosion
Intergranular Corrosion
Corrosion of Piping
Corrosion Process
Surface Coatings for Corrosion
Corrosion Resistant Material
Bi- Metallic Corrosion.Galvanic Corrosion
Intergranular Corrosion of Stainless Steel Tubes
Corrosion Resistant Stainless Steel Tube
Corrosion Resistance of Stainless Steel Tubes
Seawater Resistance of Stainless Steel Tubes
Corrosion Mechanism in Stainless Steel Tube
Austenitic stainless steel for timber fixings
Causes of metal corrosion in timber fixings
ASTM A262 Intergranular Corrosion Test IGC
ASTM E112 Standard Test Methods for Determining Average Grain Size
Methods of minimizing chloride stress corrosion cracking
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