Influence of Heating on the Transformation of Steel
Steel is a common material in the modern industry, and it is often necessary to heat steel in certain processes to achieve the expected effects. Generally speaking, the transformation of steel by the heat treatment process has significant effects, not only caused by the change of the internal physical structure of steel but also influenced by the microstructure, grain structure and chemical composition of the steel surface. In order to select the best heat treatment method, it is necessary to analyze the influence of heating on the transformation of steel.
Firstly, heating can cause physical changes in the steel itself, such as increasing the malleability, plasticity, and ductility of the steel. When heated to a certain temperature, the austenite grains will change, resulting in an increase of the grain size resulting in decreased hardness, increased malleability and plasticity. At the same time, the ductility of the steel increases and the steel becomes softer and easier to deform, making it easier to process. In addition, the internal structures of the steel can also change, leading to molecular changes, resulting in a decrease in the strength of the steel.
Secondly, the microstructure of the steel surface changes as well. As the temperature of the steel increases, the steel becomes softer and its strength decreases. In terms of the microstructure, the martensitic transformation processes can be triggered, resulting in the formation of martensites, which have higher hardness and strength than the original steel due to its different microstructure. As a result, the mechanical properties of the steel are also changed.
Thirdly, the grain structure of the steel also changes due to the heat. As the temperature of the steel increases, the grain structure of the steel begins to grow at an increased rate, leading to an increase in the grain size and an overall decrease in the strength of the steel. At the same time, the grain structure becomes finer, making the steel weaker and more susceptible to the cold processing and forming process. Heating can also lead to distortions and heat treatment defects such as quenching cracks.
Last but not least, the chemical composition of the steel can also be affected by the heat. When under the high temperature, the grain boundary between the different elements of steel will move and combine with each other, resulting in a certain change in the chemical composition, which further leads to the change of the electrical and thermal properties of the steel. The corrosion resistance of the steel will also be reduced by the heat treatment.
In conclusion, heating can have significant impacts on the transformation of steel, including changes to its physical structure, microstructure, grain structure and chemical composition. Due to these factors, it is critical to choose the appropriate heat treatment process for steel in order to avoid deformations and other heat treatment-related defects.
