In the case of common coarseness of flanges, different steel grades and different winding methods have different fatigue limit reduction degrees, such as the decrease degree of hot coil flanges is smaller than hot coil flanges. Practice shows that cadmium plating can greatly increase the fatigue limit of flange. The flange operating under the premise of high temperature should consider the use of heat resistant steel.

There is a certain connection between the yield strength of the flange and the fatigue limit. Generally speaking, the higher the yield strength of the material is, the higher the fatigue strength is. Therefore, the fatigue strength of the traveling flange should be determined by the yield strength of the traveling flange material, or the material with a high ratio of yield strength and tensile strength should be selected. Therefore, the standard effect should be considered when calculating the fatigue strength of flange.
The influence of corrosion on the fatigue strength of flange is not only related to the number of times the flange is subjected to variable load, but also related to the number of working life. As the surface roughness increases, the fatigue limit decreases. Therefore, the operation life should be taken into account when planning and accounting for flanges affected by corrosion.
Meet exists in the inclusion is to stress on the surface of the source, can lead to inclusion and matrix interface between fatigue cracks prematurely, the greater the effect of material standard, flanges standard for all kinds of cold and hot working technology of defect, the higher the possibility of surface defects, the greater the likelihood function of these reasons will lead to fatigue. The smaller the roughness of the material surface, the smaller the stress convergence, the higher the fatigue strength.
The fatigue limit of steel increases when the temperature is lower than room temperature. The fatigue strength of carbon steel drops from room temperature to 120℃, rises from 120℃ to 350℃, and drops after the temperature is higher than 350℃. There is no fatigue limit at high temperature, grinding, strong pressure, shot blasting and rolling of the material surface.
Flange surface condition Large stress is mostly produced in the surface of flange material, so the surface quality of flange has a great influence on the fatigue strength. When the corrosive medium flange works in the corrosive medium, it becomes the fatigue source because of pitting corrosion on the surface or grain boundary corrosion on the surface. Under the action of variable stress, it will gradually expand and lead to cracking. Because the steel hot coil flange and its heat treatment heating, because of oxidation of the flange material surface becomes coarse and decarburization phenomenon, so as to reduce the fatigue strength of the flange.