EoW May 2010

technology news

Heat treatment of steel spring wire

Wire-size change is also carried out automatically within the range of wire diameters allowed by the post-Curie heating inductors. A laser device detects the new wire diameter and this value is sent to the control system of the heat treatment section. Recipe change is made at the appropriate time, without stopping the line and without the intervention of the operator. Medium frequency/high frequency converters or high frequency/high frequency converters supply the pre-Curie and post-Curie hardening multistage inductors according to the range of treated wire diameters and the production rate. The advantages of induction heating over conventional furnace heat treatment are said to include high line speed with consequent high production rate; repeatable and controlled characteristics in the wire cross-section and length; a more energy efficient system and a cleaner working environment for the operator. Mario Frigerio SpA – Italy Fax : +39 0341 368385

Mario Frigerio and ATE have worked together to develop a continuous line for the production of tempered wire for springs. The line features a specifically designed product handling system and in-line induction heating with water quenching. The new line can handle a wide range of wire diameters. Wire size changes and welding are performed robotically. The process is fully automated and all checking, diagnostic, recording and working functions are controlled by an industrial PC. For cold manufacturing of high performance coil springs it is necessary to use alloyed steel wire with high tensile strength and reduction area properties. These characteristics are imparted to raw alloyed steel wire through the heat treatments of hardening and tempering. Using induction heating for the hardening and tempering process allows different mechanical properties to be obtained using a variety of time and temperature cycles. The Mario Frigerio/ATE designed system offers reliable time- temperature cycles that provide fast and uniform heating, maintaining the wire at the required temperature for the time necessary to give the specified metallurgical characteristics. A recipe is stored for each wire size. During production, the same or different types of wire can be queued without stopping the line. When appropriate, the control system sends specific data to the various units to apply the appropriate wire heat treatment. When a working coil is approaching its end the coil change procedure is automatically selected, and the coil ends are welded in-line.

Email : info@mariofrigerio.it Website : www.mariofrigerio.it ATE – Italy Fax : +39 0444 562373 Email : info@ate.it Website : www.ate.it

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EuroWire – May 2010