When Was Stainless Steel Invented?

The difference between stainless steel and traditional steel in terms of anti-corrosion performance is mainly reflected in the following aspects:

Alloying Elements: Stainless steel contains a high proportion of chromium and other alloying elements (such as nickel, molybdenum, etc.), these alloying elements can form a dense oxide film layer, thus effectively preventing further erosion of the metal surface by oxygen, water and other chemicals.

Ferrite and Austenite: The different proportions of ferrite and austenite in stainless steel result in a different crystal structure than that of ordinary steel. This crystal structure makes stainless steel have better corrosion resistance.

Surface Treatment: Stainless steel surface after polishing and other treatments can form a smoother surface, the surface is more difficult to be corroded.

Application Areas: Stainless steel is widely used in areas that require corrosion resistance, such as pharmaceutical, food processing, chemical industry, etc., while traditional steel is mainly used in construction, machinery manufacturing and other fields.

There are also some differences between stainless steel and conventional steel in terms of strength and hardness. Compared to ordinary steel, stainless steel has higher strength and hardness. This is due to the addition of a variety of alloying elements in stainless steel, such as chromium, nickel, molybdenum, etc. The addition of these alloying elements can improve the strength and hardness of stainless steel, and does not reduce its corrosion resistance. In addition, stainless steel also has higher ductility and toughness, which means it can better withstand stress and deformation without breaking or fracturing.

In contrast, conventional steel may be less strong and harder, but also has better machinability and malleability. Conventional steel is also relatively inexpensive to manufacture because it requires fewer alloying elements and the production process is relatively simple. However, conventional steel has poor corrosion resistance and is susceptible to oxidation and corrosion, making it unusable in some special environments.

Stainless steel and traditional steel also differ in terms of coefficient of thermal expansion. The coefficient of thermal expansion is the rate of change of physical quantities such as length, area and volume when an object changes in temperature. Because stainless steel contains elements such as chromium and nickel, its coefficient of thermal expansion is relatively low, so the shape and dimensions of stainless steel change less when the temperature changes. In contrast, conventional steel has a relatively high coefficient of thermal expansion and therefore has a large change in shape and size when the temperature is changed.

This property makes stainless steel more suitable for use in high or low temperature environments, such as in the chemical, aerospace, and nuclear industries. In these application scenarios, there are large changes in temperature, and the low coefficient of thermal expansion of stainless steel can reduce the shape and dimensional changes caused by temperature changes, thus improving the stability and reliability of equipment and components.

Stainless steel and conventional steel also differ in terms of welding performance. Because of the many alloying elements added to stainless steel, its melting point is higher than that of ordinary steel, and its thermal conductivity is lower, so it requires higher welding temperature and longer welding time. At the same time, stainless steel is prone to oxidation during welding, so it needs to use some special welding methods and equipment, such as inert gas shielded welding, to avoid defects such as oxidation and cracking at the weld. In addition, the heat-affected zone (Heat-Affected Zone, HAZ) of stainless steel is more prone to brittle fracture than ordinary steel, so it is necessary to control the welding temperature and welding speed when welding to avoid the problem of brittle fracture.

The difference between stainless steel and traditional steel in terms of sanitary performance is mainly manifested in the following aspects:

Stainless steel surface is smooth, burr-free, easy to clean and disinfect, will not breed bacteria and viruses. While the traditional steel surface may have burrs, bumps, it is difficult to achieve a thorough cleaning effect.

Stainless steel is added with chromium and other elements, can form a dense oxide protective film, with a certain degree of corrosion resistance, can be in different environments for a long time to maintain a smooth, flat surface. The traditional steel lack of this oxide protective film, easy to rust, corrosion, affecting hygiene.

Stainless steel has a high corrosion resistance, can withstand a variety of strong acids, strong alkalis and other corrosive media, will not produce secondary pollution. And traditional steel in contact with strong acids, strong alkalis and other corrosive media are prone to corrosion, secondary pollution.

In summary, stainless steel has obvious advantages in sanitary performance, widely used in pharmaceutical, food, medical equipment and other fields, to become one of the important materials to protect public health.