Quality requirements for wire steel of automobile suspension springs
2021-04-12 18:38:54
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Quality requirements for wire steel of automobile suspension springs
The wire used for car suspension springs has strict requirements on steel purity, dimensional accuracy, and surface quality. Practice has proved that the diameter accuracy of the wire is of great significance for reducing the wear of the wire drawing die, reducing energy consumption, reducing wire breakage, and ensuring stable drawing.
The diameter tolerance of the wire used in the suspension spring is controlled within ±0.2mm, and the ovality is not more than 60% of the diameter tolerance. Cracks, folds, scratches and other defects on the wire surface seriously affect the quality of the steel wire and reduce the fatigue life of the suspension spring. The surface of the wire should be smooth without cracks, folds, scars, etc.
The size of local defects such as bumps, pits, and pitted surfaces shall not be larger than 0.10mm. The mechanical properties of the wire should be very good, and the fluctuation should be small. The tensile strength of wire rods fluctuates ≤40MPa, the reduction of area fluctuates ≤15%, and the volume fraction of sorbite is ≥85%. The free ferrite has a greater influence on the fatigue life, and the volume fraction should be controlled within 1.5% ，The grain size is above grade 8, without martensite.
