殘余應力是材料在變形過程中或鑄件生產過程中的不均衡塑性變形，或是對它們進行機械加工、熱處理及焊 接等作業時所引進的。軋制板材時，若軋直徑小，則在表層產生壓縮殘余應力，若軋輥直徑大如平整一壓光軋制時，則板材表層部分為拉伸應力而在中 心部分為壓縮應力。
Residual stress refers to the unbalanced plastic deformation of materials in the process of deformation or casting production, or is introduced when they are machined, heat treated and welded. When rolling the plate, if the rolling diameter is small, the compressive residual stress will appear on the surface. If the roll diameter is large, such as flat calendering rolling, the tensile stress will appear on the surface and the compressive stress will appear on the center.
軋制后板材沿厚度在軋制方向上表層殘余著拉應力，內層金屬殘余著壓應力，固溶處理時板材被加熱到再結晶溫度以上，軋制過程中所形成的殘余內應力得以消除。
After rolling, the residual tensile stress in the surface layer and the residual compressive stress in the inner layer along the rolling direction of the thickness of the plate. During solution treatment, the plate is heated above the recrystallization temperature, and the residual internal stress formed in the rolling process is eliminated.

將加熱后的板材快速放入冷水槽中或噴水淬火，此時由于表面金屬冷 卻得比內層的快，淬火初期表層金屬劇冷、急劇收縮，基于板材的整體性，表層金屬產生拉應力，內層金屬產生壓應力，隨著板材的進一步冷 卻，使內層金屬劇冷、急劇收縮，使應力重新分配，導致表層金屬殘余壓應力內層金屬殘余拉應力，與其軋制過程殘余的內應力分布規律正好相反。
The heated plate is quickly put into a cold water bath or quenched by water spray. At this time, because the surface metal cools faster than the inner layer, the surface metal cools sharply and shrinks sharply at the initial stage of quenching. Based on the integrity of the plate, the surface metal generates tensile stress and the inner metal generates compressive stress. With the further cooling of the plate, the inner metal cools sharply and shrinks sharply, which redistributes the stress, The results show that the residual compressive stress of the surface metal and the residual tensile stress of the inner metal are opposite to the distribution of the residual internal stress in the rolling process.
殘余應力大小決定于材料性質、形狀及熱處理條件等。就材料性質來說，在一般情況下，熱導率越高、熱膨脹系數越小彈性模量越低、高溫強度越低，殘余應力就越小。
The magnitude of residual stress depends on material properties, shape and heat treatment conditions. In general, the higher the thermal conductivity, the smaller the coefficient of thermal expansion, the lower the modulus of elasticity and the strength at high temperature, the smaller the residual stress.
此外，鑄造、焊 接等過程中都會引起殘余應力，零件裝配不當也會引發殘余應力，甚至時效處理也會有殘余應力，并引起尺寸的微小變化，在復合材料中由于材料性質的不同，不可避免地存在著殘余應力。
In addition, casting, welding and other processes will cause residual stress, improper assembly of parts will also cause residual stress, even aging treatment will also have residual stress, and cause small changes in size. In composite materials, due to different material properties, there are inevitably residual stress.