Stainless steel plates expand when heated, mainly due to the physical phenomenon of thermal expansion. The specific reasons are as follows:
1. Intensified molecular motion: When the stainless steel plate is heated, the atoms or molecules inside the metal will gain more thermal energy, causing their motion to intensify. According to the principles of thermodynamics, as the temperature rises, the average kinetic energy between molecules increases, which causes the interaction force between atoms to change, the distance between atoms to increase, and the overall volume of the metal to expand.
2. Linear thermal expansion: The thermal expansion of stainless steel is a linear expansion process, that is, the length, area and volume of the metal will increase with the increase in temperature. Usually, the expansion of the metal is along its length, and the degree of expansion depends on the thermal expansion coefficient of the metal.
3. Thermal expansion coefficient: The thermal expansion coefficient of stainless steel is a physical quantity that describes its degree of thermal expansion. Stainless steels with different alloy compositions have slightly different thermal expansion coefficients, but generally speaking, the thermal expansion coefficient of stainless steel is relatively small, but it will still expand significantly at high temperatures. Typically, the coefficient of thermal expansion of stainless steel is around 10 × 10^-6 /°C, which means that for every 1°C increase, a 1-meter-long stainless steel plate will increase in length by about 10 microns.
4. Changes in lattice structure: The lattice structure of stainless steel expands when heated. When the temperature rises, the crystal structure inside the metal becomes looser, causing the overall volume of the metal to expand. This expansion is manifested as the metal becoming larger in appearance, especially at higher temperatures, where the expansion phenomenon is more significant.
5. Stress and deformation: When a stainless steel plate is heated, if there is a temperature gradient, the expansion degree of the surface and the inside of the metal may be different, which can cause stress inside the stainless steel plate and may even cause bending or deformation. However, under normal circumstances, if the heating is uniform, the expansion is uniform.
Summary: The main reason for the expansion of stainless steel plates when heated is the phenomenon of thermal expansion. When the temperature rises, the vibration of the atoms inside the metal increases, resulting in an increase in the distance between the atoms and an overall volume expansion. This expansion degree is affected by the thermal expansion coefficient of the material and the temperature change.
