Nitrogen gas spring (referred to as die gas spring or nitrogen gas spring or nitrogen cylinder or nitrogen cylinder) is a new type of elastic component that uses high-pressure nitrogen as the working medium. It is small in size, large in elasticity, long in stroke, stable in work, precise in manufacturing and long in service life , The elastic curve is flat, and does not require pre-tensioning, etc., so when we use it often, we need to pay attention to judging the degree of fatigue, and then protect it. Let's take a look at the following.
1. Nitrogen spring yield strength There is a certain relationship between the yield strength of materials and fatigue. Generally speaking, the higher the yield strength of the material, the higher the fatigue strength. Therefore, in order to increase the fatigue strength, we should try to increase the yield strength of the material. Or use materials with a high ratio of yield strength to tensile strength. For the same material, the fine grain structure has a higher yield strength than the coarse and fine grain structure.
2. The surface state stress mostly occurs on the surface of the nitrogen spring material, so the surface quality has a great influence on the fatigue strength. Defects such as cracks, flaws and scars caused by materials during rolling, drawing and coiling are often the causes of fatigue fracture.
3. The larger the size of the size effect material, the higher the possibility of defects caused by various cold working and hot working processes, and the greater the possibility of surface defects. These reasons will lead to a decrease in fatigue performance. Therefore, the influence of the size effect should be considered when calculating the fatigue strength of the nitrogen gas spring.
4. Metallurgical defects Metallurgical defects refer to the segregation of non-metallic inclusions, bubbles, elements, etc. in the material. The inclusions on the surface are the source of stress concentration, which will cause premature fatigue cracks between the inclusions and the substrate interface. The use of vacuum smelting, vacuum pouring and other measures can greatly improve the quality of steel.
