January 17th, 2020

Innovative Spring Wire Induction Temper Lines

By Shawn Martin


Radyne spring wire induction temper (IT) lines are revolutionizing the spring wire industry. Traditional methods of hardening and tempering spring wire have proven shortcomings. The Radyne IT line is highly automated, runs continuously, provides for increased throughput and contains an environmentally friendly water quenching medium. These factors combined mean high strength spring wire with greater consistency for the end-user.

What is spring wire and how is it used in the world?

Spring wire is a common name given to a range of steel wires prominently used in the manufacture of industrial and automotive springs. Inclusive of low-alloy manganese, medium-carbon and high-carbon steel wires, spring wire is a hardened and tempered steel alloy with exceptional yield strength. Other materials are incapable of undergoing deformation without losing their parent shape. Spring wire differs as it retains its physical shape after undergoing an appreciable amount of strain. It is an inherently resilient material with excellent elastic behavior.

How is spring wire important to businesses or consumers?

Businesses and consumers require spring wire for numerous applications including general mechanical springs, automotive suspension systems, garage door springs, automotive engine valves and even aircraft engines. Higher-strength spring wire with a greater reduction of area not only increases the fatigue rate and life expectancy of these end-use products, it also supports cold coiling processes as additional heat treatments are not performed after cold coiling.

What are the current methods of manufacture?

Traditional methods of manufacturing springs involve heating discrete lengths of wire in a furnace, up to temperatures in the region of 1000° C. The hot wire is wrapped around a mandrel to create the wound spring. While the wire is still hot, it slides free of the mandrel and drops into an oil quench tank in which the steel hardens. After exiting the quench tank, the hardened spring is tempered, possibly in a batch furnace.

Recently, oil tempering (OT) has been developed as a continuous process. This involves heating the wire through a very long furnace which is either gas-fired or electrically heated. The wire is then passed through an in-line oil quench tank, hardening the steel. Subsequently, the wire then runs through a tempering zone. Typically, this requires the use of molten lead baths. OT lines are not without their intrinsic operational and environmental issues.

To read the full article, please visit InductothermHW.com.