Properties and Selection of Stainless Steel in Different Corrosive Environments
Abstract
Stainless steel is one of the most widely used materials in a variety of industries. As a kind of alloy steel, it has the advantages of corrosion resistance, heat resistance, low temperature strength, and wear resistance. Different corrosive environments have different requirements for stainless steel. This paper introduces the properties and selection of stainless steel in different corrosive environments.
Introduction
Stainless steel is an alloy made of chromium, nickel, manganese and other corrosive resistant raw materials. It has relatively high strength and is resistant to erosion. It can withstand high temperatures and low temperatures, so it is widely used in the industrial industry, mechanical industry, construction industry, chemical industry and other fields. The combination of chromium and nickel will form a protective film on the surface of stainless steel that can effectively resist the oxidation of acid, alkali and salt and other erosive solutions. In different corrosive environments, the properties and selection of stainless steel are different, so it is necessary to select the best material according to the actual situation.
Properties of stainless steel in different corrosive environments
1. Acidic corrosion environment
The properties of stainless steel in acidic and alkaline corrosion environments are completely different. In the acid environment, chromium alloy steel is the best choice, such as 304 and 316 stainless steel, because these steels have high Cr and Ni content and can effectively resist the corrosion of acid.
2. Alkaline corrosion environment
In the alkaline corrosion environment, the corrosion resistance of chromium alloy steel cannot meet the requirements. Therefore, stainless steel with high molybdenum content should be used, such as nickel-base and molybdenum-base alloy steel containing more than 10% molybdenum.
3. Salt water corrosion environment
In the salt water corrosion environment, 318L and S31603 stainless steel should be selected. Due to the high content of molybdenum, 318L stainless steel has strong corrosion resistance. S31603 stainless steel has higher strength and can resist different media corrosion, but its weldability and plasticity will be affected.
4. High temperature corrosion environment
In the high temperature corrosion environment, stainless steel with good oxidation resistance and high temperature strength, such as 309L, 310L and 310H stainless steel, should be chosen. 309L and 310L stainless steel have higher chromium content and can resist oxidation and high temperature corrosion. The disadvantage is that their corrosion resistance is not very good. 310H stainless steel has higher carbon content and better mechanical properties, and can be used for long-term operation at 800℃.
5. Low temperature corrosion environment
In the low temperature environment, stainless steel with excellent low temperature resistance and good plasticity, such as 904L, 2205, 2207, 316L and 825, should be selected. 2205 and 2207 stainless steel have higher Cr and Ni content and good plasticity and weldability, but their strength and oxidation resistance are not as good as 904L and 316L stainless steel.
Selection of stainless steel in different corrosive environments
1、In metallic and non-metallic materials corrosive environment
For metallic and non-metallic corrosive environments, it is advisable to choose stainless steel containing chromium and nickel, such as 304 stainless steel, 316L stainless steel and 330 stainless steel, which can meet the requirements of corrosion resistance, heat resistance and low temperature strength.
2、In organic solvent corrosive environment
When organic solvents are used as corrosion media, a variety of stainless steel can be selected according to the corrosion structure of organic solvents. When organic acids are used as corrosion media, austenitic chromium-nickel stainless steel with low carbon content, such as 304L, 316L and 312L, should be selected. When alkali solvents are used, it is advisable to choose nickel-based base or molybdenum-based alloy steels containing more than 10% Mo, such as 321 and 347 stainless steel.
3、In sulfuric acid corrosive environment
When sulfuric acid is used as corrosive medium, 316L stainless steel, 309L stainless steel and 310L stainless steel should be used. These stainless steel contain higher chromium content, which can make the stainless steel more resistant to sulfuric acid corrosion.
Conclusion
In different corrosive environments, stainless steel has different properties and selection methods. When stainless steel is used, we should select the most suitable material according to its actual application requirements and properties. In this paper, we have focused on the properties and selection of stainless steel in different corrosive environments.
