The unique characteristics of stainless steel are manifested due to the chemical composition and structure of materials.
The steels included in the stainless steel group are divided into four groups depending on the specified parameters:
- Chromium or ferritic.
This group of steels got its name because of the 20% chromium content. It greatly increases the resistance of the metal to aggressive environments. The ferromagnetic properties of this group of stainless steel are quite high.
Monel 400 Pipe are used in industrial plants related to the chemical and heavy industries. They are used for making, for example, heating devices and their parts. This stainless steel group is in great demand on the market, second only to the category with an austenitic structure. However, their cost is significantly lower.
- Austenitic steels.
In the chemical composition of stainless steels of this group, the content of nickel and chromium is not more than 33%. Buyers appreciate the material's significant strength and near-absolute corrosion resistance.
Steels belonging to the austenitic group are subdivided into the following types:
A1 - sulfur is present in the composition of this material significantly, which reduces the anti-corrosion resistance, unlike other steels.
A2 is the most demanded brand. This material is excellent for welding without losing the thermophysical properties of stainless steel. It is resistant to subzero temperatures, but an aggressive acidic environment can break its anti-corrosion protection.
A3 is the A2 grade with the addition of various stabilizing components. Resistant to both acidic environments and elevated temperatures.2507 Pipeis also widely used.
A4 - no more than 3% molybdenum is added to this alloy. Its effect on the properties of stainless steel is to increase its resistance to acidic environments. This brand is widely used in the construction of ships.
A5 is similar to A4 grade, differing only in the amount of stabilizing additives. It is made to increase resistance to high temperatures.
- Ferritic-martensitic and martensitic.
The special structure of these alloys gives them extremely high strength - the best of all, steels. In addition to the above, they contain a minimum of harmful impurities in the composition and are distinguished by excellent wear resistance. This category includes heat-resistant corrosion-resistant steel. It actively resists oxidation processes and can be used continuously at high ambient temperatures while maintaining stainless steel's original composition and properties.
- Combined.
Popular stainless steel grades, properties of these alloys and their areas of application
The structure of the steels of this group has a combined type: austenitic-martensitic and austenitic-ferritic. This group's innovative materials combine all the best properties of stainless steel previously described, including magnetic.
The above steel types are not all stainless steel types. This is because even a small change in the alloy ratio can dramatically change stainless steel properties. Data on the belonging of the alloy grade to a particular group makes it possible to choose the optimal material that will help solve technological problems.
40X9S2 - this steel is used in the production of valves for engines. It is heat-resistant.
14Х17Н2 - designed for equipment operating at ultra-high temperatures (up to +800 ° С).