Pu Steel Wire Hose maintains outstanding resistance to bending fatigue when used under compliant working conditions. Conventional repeated bending will not cause cracking, which serves as one of its core advantages over ordinary plastic hoses and rubber hoses. The hose is integrally extruded from high-elasticity polyurethane raw materials. The pipe wall itself features good flexibility, tensile resistance and tear resistance. Combined with the embedded spiral steel wire skeleton structure, stress generated during bending can be evenly distributed to avoid concentrated force on partial pipe walls. This structurally prevents damage caused by single or multiple conventional bends, adapting to dynamic working scenarios such as reciprocating equipment movement and multi-angle bending.
Nevertheless, cracking of the hose after repeated bending is not an inherent defect of the material. It is mostly triggered by three major factors: working conditions, product quality and aging loss. The first factor is excessive bending angle. Each type of Pu Steel Wire Hose has a specified minimum bending radius. If sharp-angle folding or extreme bending beyond the radius occurs frequently in application, the pipe wall will continuously bear strong extrusion and stretching forces. Friction loss will persist at the contact points between the steel wire and pipe wall. After long-term accumulation, tiny fatigue cracks will form on the pipe wall and expand gradually, leading to cracking, air leakage and material leakage. The second factor is environmental influence. At low temperatures, PU material will harden gradually with decreased toughness and sharply increased brittleness. At this time, repeated bending deprives the pipe wall of normal deformation buffering, so cracking happens rapidly. Long-term outdoor sunlight exposure, contact with acid-base materials, oil stains and chemical solvents will erode the molecular structure of the pipe wall, resulting in aging and embrittlement of the material and a sharp decline in bending resistance.
Product quality difference also plays a vital role. High-quality Pu Steel Wire Hose adopts brand-new virgin polyurethane pellets with high purity, sufficient toughness and strong fatigue resistance, which can withstand tens of thousands of conventional bends without damage. In contrast, inferior products mixed with recycled materials and fillers have uneven pipe wall texture, poor toughness and tiny internal pores and impurities. Stress tends to concentrate at impurities during bending, and cracking emerges after short-term repeated bending. In addition, accumulated service loss accelerates damage. Long-term high-frequency bending will bring irreversible fatigue aging to the pipe wall and slight deformation of the steel wire skeleton. Even under normal working conditions, cracking will gradually occur after the service life expires.
To avoid cracking caused by repeated bending, users must operate in accordance with the marked minimum bending radius of the hose and prohibit sharp folding. Special PU hoses with low-temperature resistance shall be selected for low-temperature working conditions. Long-term contact with corrosive media should be avoided, and the aging state of the pipe wall should be inspected regularly. Meanwhile, users should purchase high-quality products made of regular virgin materials to improve the service life of bending resistance from the source and reduce cracking failures. Overall, Pu Steel Wire Hose with compliant application and matched working conditions has a far longer bending resistance life than ordinary hoses. Cracking is mostly caused by improper use and environmental degradation.