Common alloying elements and their functions in heat-resistant steel

Heat resistant steel can maintain good performance in high temperature environments without the addition of various alloying elements. These elements each play a unique role in enhancing the performance of heat-resistant steel.

Chromium (Cr) is a key element in heat-resistant steel that enhances its oxidation resistance. It forms a dense chromium oxide film on the surface of the steel, which acts as a strong shield and effectively prevents oxygen from further diffusing into the interior of the steel, thus protecting it from oxidation. Meanwhile, chromium can enhance the high-temperature strength and hardness of steel, making heat-resistant steel more durable at high temperatures.

Nickel (Ni) can significantly improve the toughness and fatigue resistance of steel. In high-temperature environments, steel is prone to fatigue cracks due to various stresses. The addition of nickel can maintain good performance of steel under repeated stress and prevent damage. Moreover, when nickel is used in combination with chromium, it can significantly improve the oxidation resistance and corrosion resistance of heat-resistant steel, allowing it to work stably even in harsh high-temperature corrosive environments.

The main function of molybdenum (Mo) is to improve the high-temperature strength and creep resistance of steel. Under long-term high temperature and load, steel will undergo slow plastic deformation, namely creep phenomenon. Molybdenum can effectively suppress this deformation, enhance the durability of steel at high temperatures, and ensure that heat-resistant steel maintains stable shape and performance during long-term high-temperature operation.

Elements such as vanadium (V) and titanium (Ti) can form small carbides. These carbides are dispersed and distributed in the structure of steel, playing a role in precipitation strengthening, like adding countless tiny "nails" to steel, improving its strength and hardness, and enhancing its high-temperature performance.

It is the synergistic effect of these alloying elements that endows heat-resistant steel with excellent properties, enabling it to be widely used in many high-temperature industrial fields.