Explanation

The performance of alloy after solution treatment or deformation changes with time at room temperature or higher temperature. Usually, the strength and hardness increase with time, and the plasticity and toughness decrease, which is called age hardening; In recent years, the continuous strength and hardness of low carbon steel without recrystallization control or ultra fast cooling after hot rolling decrease with time, accompanied by improvement of plasticity and toughness, which is called aging bating. Performance changes are often accompanied by changes in shape and size. The main reasons for aging are: supersaturated solute desolvation precipitation produces precipitated phase precipitation strengthening, commonly known as quench aging; Air mass formed between interstitial solid solution atoms and dislocations is strengthened, which is usually called strain aging; The dissipation of inner stress and recovery of high density dislocation after deformation or ultrafast cooling produce bating, which is called aging bating. The aging phenomenon can improve the specific properties of materials. For example, age hardening steel is usually supplied in aging state to obtain high strength; After strain aging, the strength of building steel bars and automotive deep drawn parts should be properly improved, and the yield point phenomenon should reappear, which is conducive to safety. However, aging must be paid attention to and prevented from reducing other properties, for example, strain aging often leads to a significant reduction in plasticity and toughness; aging bating will lead to the strength of rolling high strength steel significantly reduced; The deformation of castings after aging will reduce the shape and dimensional accuracy of products. In some cases, aging treatment can be carried out in advance to eliminate the adverse effects of aging.

Classification