Stainless acid resistant steel

Stainless acid-resistant steel, also known as stainless steel and acid-resistant steel, can be divided into two categories according to its main use in industry: stainless steel and acid-resistant steel. The following is a detailed introduction to these two types of stainless acid-resistant steel:

Stainless steel

Definition: Steel that resists corrosion in air is called stainless steel. This steel is not necessarily acid-resistant, and although its chromium content is usually above 13%, corrosion can still occur in certain environments.

Chemical composition: Stainless steel contains a high proportion of chromium, usually more than 13%, and some even as high as 25%. In addition, it also contains elements such as nickel, molybdenum, vanadium, copper, manganese and nitrogen, the addition of which can significantly improve its corrosion resistance and mechanical properties.

Applications: Stainless steel is widely used in the manufacture of a variety of devices that require corrosion resistance, such as medical devices, food industry equipment, and daily use of knives and kitchenware.

Acid-proof steel

Definition: Acid-resistant steel refers to steel that can resist corrosion in a variety of aggressive media. Unlike stainless steel, acid-resistant steel is mainly designed for strong corrosive environments, but it is not necessarily resistant to atmospheric corrosion.

Chemical composition: Acid-resistant steel not only contains high chromium (usually 17%-25%), but also contains a large amount of nickel (up to about 20%), as well as other elements such as molybdenum, vanadium, copper, manganese and nitrogen, which work together to give steel excellent corrosion resistance in strong acid and alkali environments.

Application: Acid-resistant steel is mainly used in chemical equipment, offshore platforms, urea industry equipment and other devices that need to withstand strong acid and alkali environment for a long time.

Comprehensive analysis

Differences: Although stainless steel and acid-resistant steel both have excellent corrosion resistance, there are significant differences in their composition and specific applications. Stainless steel is suitable for general corrosive environments, while acid-resistant steel is more suitable for extreme chemical corrosive environments.

Selection suggestions: When selecting materials, the appropriate steel grade should be selected according to the specific working environment and medium. For example, for applications such as medical devices that are exposed to air for a long time and need to be kept clean, priority should be given to stainless steel; In chemical equipment and other need to face strong acid and alkali environment, acid-resistant steel is a more suitable choice.

Development history

Early development: The history of stainless steel began at the beginning of the 20th century, when Guier and Portvin et al in France, and Brearley in the United Kingdom, respectively, independently invented iron-chromium and iron-chromium-nickel alloys and found that they had good corrosion resistance.

Henry Brearley is widely regarded as one of the inventors of modern stainless steel, having patented it in 1912. Since then, Monartz proposed the theory of rustlessness and passivation, which further promoted the development of stainless steel.

Technological progress: With the continuous progress of metallurgical technology, the performance of stainless steel and acid-resistant steel has been significantly improved. Today, there are many different types of stainless steel and acid-resistant steel used in various fields to meet different industrial needs.

By understanding the classification, chemical composition, application fields and development history of stainless steel, the characteristics and advantages of this material can be better understood, and scientific basis for industrial applications can be provided.