Effect of austenitization on grain size and hardness of Nb-containing NM500 low-alloy high-strength wear-resistant steel
Austenitization is a common heat treatment process applied to steel. It is a process of heating steel to a certain austenitization temperature, holding it and cooling it at a certain rate. During the austenitization process, various transformations of the microstructure of steel occur, such as grain refinement, changes in the amount of retained austenite and pearlite, and changes in the shape of austenitic grains. The austenitization temperature of Nb-containing NM500 low-alloy high-strength wear-resistant steel is generally above 830°C.
Grain refinement is an important transformation during austenitization, which is mainly affected by the austenitization temperature and holding time. As the austenitization temperature increases, the grain size decreases and the grain refinement of steel is improved. However, because the grain size of steel is closely related to the carbon content, higher austenitization temperature can cause the carbon content to decrease and the grain size to increase. Therefore, it is necessary to select an appropriate austenitization temperature and holding time to obtain an ideal grain refinement.
The amount of retained austenite in steel is also affected by austenitization. Generally speaking, higher austenization temperature can promote the transformation of the microstructure, precipitate the sodium of contained austenite, and increase the amount of retained austenite at the same time. The increase of retained austenite changes the hardness of steel, so that the hardness of steel can be increased after austenitizing.
The shape of austenitic grains is another transformation that occurs during austenitization. As the austenitization temperature increases, the shape of austenitic grains will gradually become blocky and coarse. Meanwhile, steel in the annealing process can form an interlaced structure, resulting in a higher strength and wear resistance.
In general, austenitization has an important influence on the microstructure and hardness of Nb-containing NM500 low-alloy high-strength wear-resistant steel. By controlling the austenitization temperature, holding time, and cooling rate, it is possible to obtain a satisfactory grain refinement and higher hardness.
Influence of austenitization on grain size of Nb-containing NM500 low-alloy high-strength wear-resistant steel
Influence of austenitization on hardness of Nb-containing NM500 low-alloy high-strength wear-resistant steel
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