It was discovered well before the turn of the century that it is possible to remedy the corrosion of A234 WPB steel by adding nickel and chromium. However, the steels enriched with these elements still left something to be desired. A significant change took place in Germany in 1912. For the first time and thanks to the combination of nickel and chromium combined with a precise metering heat treatment, it was possible to obtain an optimal resistance to corrosion at the same time as good mechanical properties.
Material Properties And Advantages
Stainless steel is an Austenitic acid-resistant Cr-Ni alloy steel of 18/10, which, thanks to its reduced hydrogen content, has very good anti-corrosion properties. For higher temperatures, it is essential to use titanium-stabilized A420 WPL6 steel. Steel is resistant to water, steam, atmospheric humidity, and food acid, as well as weak organic and inorganic acids, and is very versatile in its employment possibilities: food industry, production of beverages, pharmaceutical, and cosmetic industries.
The advantages of stainless steel are as follows:
- corrosion-resistant
- resistant to temperature variations
- antistatic
- solderable
- hygienic
- maintenance-free
- durable
THE FOLLOWING TYPES OF CORROSION CAN OCCUR IN STAINLESS STEEL:
- a) Intercrystalline
corrosion This corrosion takes place when chromium carbides are released critically on the contour of the grains. The environment then loses chromium, which reduces the passivation effect. Materials 1.4541, 1.4571, and 1.4435, alloy steel plate, can be considered to be resistant to intercrystalline corrosion.
- b) Pitting corrosion
In the case of this corrosion, the carbon steel plate is only broken at certain points. The result is that pits or holes form on the exterior. Pitting corrosion is caused mainly by halogen ions, particularly chlorine ions. It can be reinforced above all by water and wastewater, often linked to the presence of chlorine and chloride ions.
- c) Galvanic corrosion
This corrosion is very frequent and is created when a metallic c45 plate of different potential comes into contact in the presence of an electrolyte. In this case, the less noble metal is attacked by the electrolyte and dissolves. The extent of corrosion is proportional to the amount of electricity circulating in this galvanic element. This type of corrosion is very common. One of the best-known examples of this corrosion is the bonding of steel and stainless steel flanges. d) Cavernous
This corrosion takes place when the passive layer of carbon steel flanges is destroyed, for example, by the presence of corrosive products combined with a lack of oxygen. Therefore, this type of corrosion is common in narrow and small carbon steel flanges, for example, underseals under nut heads.
Cleaning and maintenance
For the removal of fingerprints, a solution of dish soap is generally sufficient. Some manufacturers of cleaning products offer special products that have a better cleaning effect thanks to the addition of a maintenance component. In the case of tough stains, you can use standard cleaning milk, which also combats traces of lime and discoloration. After cleaning, the surface of Stainless steel pipe fittings is rinsed with clean water.