August 11, 2020 What is Stainless Steel and Why Use It?

There are a lot of types of stainless steel but there are five main ones and they are profiled here.

Stainless steel is an alloy, which means it is made up of different elements. As the name suggests, it is a type of material that doesn’t corrode. Stainless steel is a metal that contains chromium, as well as chemical impurities such as nitrogen and nickel, which provide good plasticity and toughness of the material.

What is the uniqueness of chromium? It is in its reactions with oxygen! In the presence of oxygen, a thin layer of insoluble chromium oxide forms on the surface of a stainless steel product. This oxide film creates the “super ability” of hot rolled coil steels to resist corrosion even in highly aggressive environments at elevated temperatures. The oxide layer makes the stainless alloy essentially inert: it prevents the elements of the alloy from chemically reacting with the environment, including oxidation.

There are a lot of types of stainless steel, but they can be grouped into 5 main ones:

1. Stainless steel with austenitic internal structure

This is one of the modifications of iron with a high degree of alloying. It has a face-centered crystal lattice. It easily retains its structure even at very low temperatures. The austenitic internal structure has high strength values. It is resistant to both high temperatures and heavy loads.

2. Steels with a ferritic internal structure

Modern ferritic stainless steels stand out for their corrosion resistance. They remain of high quality and in many respects are not inferior to their chromium-nickel counterparts. There are several environments in which this type of steel is superior to analogs and shows better resistance.

3. Steels with martensitic structure

Martensite crystals have a tetragonal structure where iron atoms take place in lattice sites. In appearance, martensite is represented by multiple dark needles of iron on a light background. The angle of inclination of these needles is on average 60 degrees relative to each other. It is impossible to detect traces of carbon on the surface of martensite since it is completely in a dissolved state.

4. Duplex steel structure

Duplex steel is considered the best all over the world. What characteristics does it have? Firstly, the high strength of this material allows you to reduce the final weight of any product. Secondly, it is renowned for its immense corrosion resistance. This is especially noticeable when considering resistance to stress corrosion cracking.

5. Precipitation hardening stainless steels

These steels are also called high strength stainless steels. Dispersion-hardened stainless steels contain aluminum, niobium, or tantalum and derive their properties through hardening and martensitic transformation.

Stainless steel has many benefits. First of all, this material is very strong, wear-resistant, well-formed, non-corrosive, and meets environmental standards. The period of operation of stainless steel products can reach 50 years. During this rather long period, the steel almost doesn’t lose its original properties. Moreover, the material doesn’t need additional care and periodic painting.

The elemental analysis required to produce the highest quality steel can be carried out. These are X-ray fluorescence (XRF) and optical emission spectroscopy (OES).

The first method is one of the best technologists in the field of metal processing. Portable X-ray analyzers can analyze the entire metal in a few seconds and sort it by its type.

OES is a technology for analyzing metals and alloys in laboratories. With its help, you can get a quick analysis of the elements in the material.

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