Lesjöfors, one of
Europe’s leading spring brands, identifies three common culprits for breakage
and offers advice on how to combat these to ensure the longest possible service
As a key component within a vehicle’s suspension system, coil springs must handle high levels of stress as they support the vehicles weight whilst isolating it from the road.
A spring’s lifespan comprises many millions of cycles, yet even
the best made springs will eventually grow tired and start to sag; vehicle ride
height will decrease and may become uneven, affecting vehicle handling and
braking distance. Breakage is however the main reason for spring replacement;
and the pursuit of quality reduces this risk.
Springs are constantly exposed to the elements, as well as to
stone fragments, grit salt and potholes, so need to be made from high quality
material, with their surface suitably protected from corrosion. Corrosion is
the most common cause of spring failure, reducing the cross-section of a spring
and weakening it. Defects and chips in the layer of lacquer are unavoidable,
and without additional protection, the spring steel will start to rust
immediately, leading to creep corrosion beneath the lacquer, significantly
speeding up the inevitability of breakage.
Manufacturers such as Sweden-based Lesjöfors produce springs that
are designed to withstand the ultimate test – the harshest conditions of a
Scandinavian winter. Each spring is made from the highest quality specialist
spring-steel, and protected from corrosion by zinc phosphate and epoxy powder
paint as required by the most demanding OEMs.
Poor heat treatment
Coiling a spring is only part of the job and effective heat
treatment is also vital to produce a ductile and durable spring. The chance of
premature spring failure increases if effective heat treatment isn’t applied to
remove the negative internal stresses introduced during the coiling process.
Heat treatment at the correct temperatures, and for the appropriate duration,
is critical to reduce the risk of breakage during use.
Lower quality wire
Poor quality spring wire, often with surface and inner defects,
significantly increases the likelihood of premature breakage. Even small
surface fissures or occlusions within the material can lead to premature spring
failure, and it is therefore vital to choose a supplier such as Lesjöfors that
only uses high grade specialist ‘spring’ steel from selected mills worldwide.
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