Forms of destruction of steel

Steel has two completely different forms of failure: plastic failure and brittle failure. Although the steel used in steel structure has high plasticity and toughness under normal conditions of use, there is still the possibility of brittle failure under certain conditions.

The main feature of plastic failure is that there is a large plastic deformation before the failure, and there are often obvious vertical interleaving stitch spalling lines on the steel surface. Only when the stress in the component reaches the tensile strength will the damage occur, and the fracture after the damage is fibrous and dark in color. Because there is always a large plastic deformation before plastic failure, and the deformation duration is longer, it is easy to be found and rushed repair and reinforcement, so serious consequences will not occur. The large plastic deformation ability of steel before plastic failure can realize the redistribution of internal forces in members and structures, and the plastic design of steel structure is based on this sufficient plastic deformation ability.

The main characteristic of brittle failure is that the plastic deformation is small or no plastic deformation before failure, and the sudden and rapid fracture. After destruction, the fracture is flat and straight, with glossy grain or herringbone pattern. Because there is no warning before the brittle failure, the damage speed is very fast, can not be detected and remedied, and once the damage of the entire structure often occurs, the consequences are very serious, so the design, construction and use of steel structure, special attention should be paid to prevent the occurrence of such damage.