The alloying elements in stainless steel are nickel and chromium, with chromium providing corrosion resistance and strength. Nickel provides strength and also some corrosion resistance.
In metallurgy, stainless steel is a steel alloy with a minimum of 11% chromium content by mass. The benefit of stainless steel is that it does not rust or stain as ordinary steel. In fact, it is also called corrosion-resistant steel. As suggested, there are different grades and surface finishes of stainless steel. It adapts to the environment it finds itself in.
Martensitic steel for cutlery use
One of the groups stainless steel can be divided into is martensitic steel – developed commercially for cutlery and which has a high carbon content compared to other grades of stainless steels. Martensitic stainless steel is indispensable for ensuring cutlery keeps its sharpness for a long time.
This stainless steel contains 12 – 17% chromium and nickel. The lower nickel content offers the advantage of lower material cost but which are low maintenance and strong.
Of all the corrosion-resistant alloys, martensitic stainless steels are the most common and have the advantage of normal steels – cost-effective, easy to manufacture, strong and available in many product forms.
AISI 420 stainless steel is martensitic stainless steel that is formed into wrought products. It is a steel with higher carbon content and 12% (minimum) chromium content, and it can be hardened through heat treatment. It also offers excellent corrosion-resistant characteristics when polished.
Stainless steel grades alike to 420-grade stainless steels comprise martensitic steels as well as the 440-grade series. Grade 420 steels are resistant to air, some acids, freshwater and foods. This stainless steel also has a scaling resistance at temperatures as high as 650°C, but temperatures above regular tempering temperatures are not suitable.
Corrosion the enemy of steel
Steel corrosion refers to the irreversible deterioration of the steel as well as its vital properties due to environmental factors. Seawater has concentrations of dissolved salts and is very corrosive to steel in marine environments. Efforts to eliminate corrosion in marine environments continue as industries look for solutions to prevent asset degradation.
The shipping and pipeline industry is always facing corrosion challenges, with the most frequent forms of corrosion on tankers, for instance, are pitting corrosion, galvanic corrosion as well as microbiologically influenced corrosion. In fact, you get every kind of corrosion out at sea as you do in the city.
For ocean applications, pipeline materials for subsea pipelines are constructed from carbon steel, although there is now a tendency for the subsea pipeline to be made from martensitic 13Cr stainless steel because of concerns with internal corrosion.
Steel is the most widely used industry in the Oil and Gas sectors and at Virgamet, we are involved with the import and export of steel on foreign markets.