Fracture at the middle section (clamped area by U-bolts, most frequent failure) this region bears the maximum bending stress under load. Possible causes include unreasonable parabolic profile leading to stress peaks, internal material inclusions, improper hardness after heat treatment, and insufficient shot peening. Alternating loads easily initiate fatigue cracks here, especially under sustained overload.
Fracture at spring eyes sharp radii at spring eyes cause severe stress concentration. Worn loose bushings bring periodic impact loads. Surface decarburization, scratches and biased loading on lifting points will further trigger crack propagation at eye sections.
Cracks at blade ends and edges unpolished blade ends retain stamping burrs and sharp notches. Without anti-friction gaskets between leaf blades, dry friction during large deformation scratches spring surfaces. Corrosion also generates tiny cracks which expand continuously.
Fracture near the shackle area bending moment fluctuates drastically during suspension travel. Improper layout of U-bolts distributes force unevenly, and continuous impact from rough roads accelerates fatigue failure.
General inducements include overload, violent impact, corrosion, inadequate pre-set compression, uneven microstructure from poor heat treatment and insufficient shot peening. Improper tightening torque of U-bolts during assembly will raise fracture risks as well.
Post time: Aug-13-2026
