PLATE - DURACORR® - CORROSION BEHAVIOR
Figure 1 Atmospheric Corrosion
The influence of chromium on the atmospheric corrosion of low-carbon steel.
Figure 2 Atmospheric Corrosion Panels
Photograph comparing three-year atmosphere corrosion test panels of Duracorr®, a registered trademark of Mittal Steel, (left)
to weathering steel (right).
Often, Duracorr®, a registered trademark of Mittal Steel, may be in contact with carbon steel in the fabrication of different products. Such a design feature may promote galvanic corrosion. When two different metals touch in a corrosive solution, a "galvanic couple" is created and accelerated corrosion of the less corrosion-resistant metal occurs. This effect can be reduced if the surface area of the carbon steel is large compared to the area of Duracorr®, a registered trademark of Mittal Steel. If the reverse is present - for example, carbon steel rivets in Duracorr®, a registered trademark of Mittal Steel, - carbon steel will corrode at a significantly higher rate. Therefore, it is important to use stainless rivets, bolts or interior structural elements, if Duracorr®, a registered trademark of Mittal Steel, is in contact with a corrosive environment.
The environment in which Duracorr®, a registered trademark of Mittal Steel, is used dictates its applicability. Duracorr®, a registered trademark of Mittal Steel,has been used in challenging corrosive applications including rail cars and equipment for processing high sulfur coal, water tanks in street sweepers, and processing equipment for sugar beets. Contact Tricon® to review other specific environmental applications.
Duracorr® Corrosion Behavior
Corrosion of stainless steel can occur by a number of mechanisms including general, galvanic, pitting, crevice, intergranular and stress. The excellent behavior of Duracorr®, a registered trademark of Mittal Steel, in general corrosion is shown in the table below, where it is compared to other metals in water with different chloride concentrations.
Corrosion Rates of Various Metals in Water (1)
Mils (0.001 inches) per year
Test Temperature = 77°F (25°C) and pH=7.0
Notes: (1) No pitting attack observed in any of the test specimens.
Notes: (2) Tap water
Notes: (3) Sea water
The benefit of chromium additions for reducing the atmospheric oxidation of steel is presented in Figure 1. Duracorr®, a registered trademark of Mittal Steel, gives it significantly improved atmospheric corrosion behavior. A comparison of the surface appearance of exposed Duracorr®, a registered trademark of Mittal Steel, and weathering steel is shown in Figure 2.